dimensions volume 06 particle a joint fermilab/slac publication … · 2019-12-31 · rhianna...

may 09

issue 02

volume 06dimensionsofparticlephysicssymmetry

A joint Fermilab/SLAC publication

symmetryA joint Fermilab/SLAC publication

On the cover:Scientists can feel like they are swimming in a sea of names in modern collaborations of more than 1000 physicists, where you’re just one on a very long A-to-Z list of authors on published results. So how can individ-uals be recognized for their efforts and distinguished from others when it comes to promotion and tenure decisions? See story on page 20.Photo-illustration: Sandbox Studio; Photos: Reidar Hahn, Fermilab

volume 06 | issue 02 | may 09

Features10 A New Leader for CERN

In his first few months on the job, CERN Director-General Rolf-Dieter Heuer opens new lines of communication, oversees repairs to the Large Hadron Collider, and promotes a worldwide strategy for particle physics based on a strong mix of global, regional, and national projects.

14 Chasing Charm in ChinaAmerican scientists are flocking to the Beijing Electron Positron Collider, whose recent upgrades make it the premier place to study charm quarks and their kin.

20 Credit Where Credit is DueIn the swirling sea of thousands of people who contribute to a major particle physics experiment, how can a young physicist pop to the surface and get noticed? An inter-national committee offers ideas.

02 Editorial: Particle Physics RevitalizedParticle physics feels like a different enter-prise compared with one year ago. Rapid scientific progress and a new budget scenario have enlivened the field.

03 Commentary: Pier Oddone “When questions arise about how the Higgs boson connects to buying another bag of groceries, we need to pay attention, because our fellow tax-paying citizens are the ones who pay the bills for US particle physics. They have a right to know what they are getting.”

04 Signal to BackgroundThe real world of Angels & Demons; CMS digs Roman history; sand and silence in Morocco; carpenters carve an ATLAS; battle of the buzzer at SLAC; what’s in your office?

08 symmetry breakingA summary of recent stories published online in symmetry breaking, www.symmetrymagazine.org/breaking

26 Gallery: Sergio CittolinA physicist sketches science in the style of Leonardo da Vinci.

30 Deconstruction: Standard Model Discoveries

Sixteen elementary types of particles form the basis for the theoretical framework known as the Standard Model of funda-mental particles and forces. Here is a brief summary of 15 Nobel Prize-winning discoveries closely connected to the development of that model.

32 Essay: Lynn Hecht Schafran “In August 2008 I built my summer vacation around a trip to CERN, the European high-energy physics laboratory near Geneva.”

C3 Logbook: Earth’s Radiation BeltsJames Van Allen barely had time to savor the launch of America’s first satellite, Explorer I, on January 31, 1958, when NASA scientists told him the Geiger tube cosmic-ray detector his team had built for the mission wasn’t working.

C4 Explain it in 60 Seconds: Charm QuarkThe charm quark is one of six quarks that, along with leptons, form the basic building blocks of ordinary matter. It is hundreds of times more massive than the up and down quarks that make up protons and neutrons.

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from the editor

symmetry

SymmetryPO Box 500MS 206Batavia Illinois 60510USA 630 840 3351 telephone 630 840 8780 fax [email protected]

For subscription services go to www.symmetrymagazine.org

symmetry (ISSN 1931-8367) is published six times per year by Fermi National Accelerator Laboratory and SLAC National Accelerator Laboratory, funded by the US Department of Energy Office of Science. (c) 2009 symmetry All rights reserved

Editor-in-ChiefDavid Harris650 926 8580

Deputy EditorGlennda Chui

Managing EditorKurt Riesselmann

Senior EditorTona Kunz

Staff WritersElizabeth Clements Calla Cofield Kathryn Grim Kelen Tuttle Rhianna Wisniewski

InternsKristine Crane Lauren Schenkman Michael Wall

PublishersRob Brown, SLACJudy Jackson, FNAL

Contributing EditorsRoberta Antolini, LNGSPeter Barratt, STFC Romeo Bassoli, INFNStefano Bianco, LNFKandice Carter, JLabLynn Yarris, LBNLJames Gillies, CERNSilvia Giromini, LNFYouhei Morita, KEKTim Meyer, TRIUMFPerrine Royole-Degieux, IN2P3 Yuri Ryabov, IHEP ProtvinoYves Sacquin, CEA-SaclayKendra Snyder, BNLBoris Starchenko, JINRMaury Tigner, LEPP Ute Wilhelmsen, DESYTongzhou Xu, IHEP BeijingGabby Zegers, NIKHEF

Print Design and ProductionSandbox StudioChicago, Illinois

Art DirectorMichael Branigan

Designers/Illustrators Andrea Butson Aaron Grant

Web Design and ProductionXeno MediaOakbrook Terrace, Illinois

Web ArchitectKevin Munday

Web DesignKaren AcklinJustin Dauer Alex Tarasiewicz

Web ProgrammerMike Acklin

Photographic Services Fermilab Visual Media Services

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Particle physics revitalizedIs particle physics rec-ognizably the same research enterprise it was a year ago? This time last year, tight lab budgets required Fermilab to implement furloughs for all staff, SLAC laid off 15 per-

cent of its workforce, and a variety of research programs in particle physics in the United States were cancelled or postponed.

As we go to press, the US Congress has passed an FY09 budget that restores many of the cuts to science funding, a proposed FY10 budget outline includes increases for science, and the president has declared, “We will devote more than 3 percent of our GDP to research and development.” This is very positive news for the science community, including particle phys-icists, and scientists are keenly digging back into their research.

Investment in basic research is a strong driver of long-term economic growth and the generator of many other benefits. The particle physics com-munity is currently working hard to make these benefits clearer to the taxpayers who provide the majority of their research funding. More still needs to be done on that front and a solid study of economic benefits is desirable, as Fermilab Director Pier Oddone comments (page 10).

We are entering a very exciting period for par-ticle physics with a renewed enthusiasm due to the budget improvements and the recent and imminent startups of many new facilities around the world. This spring, the Tevatron collider at Fermilab set one record after another, and its experiments produced a string of headline-making results. Meanwhile, the Large Hadron Collider at CERN is moving closer to having first colliding beams with repairs progressing smoothly.

The upgraded Beijing Electron Positron Collider (page 14) recently began operation, Fermilab broke ground for the construction of the NOνA neutrino experiment, and designs for SLAC’s FACET plasma wakefield particle acceleration facility are progressing quickly. The Japan Proton Accelerator Complex (J-PARC) just started send-ing a beam of neutrinos straight through the earth toward the Super-Kamiokande detector on the other side of the country.

Other accelerator-based projects are devel-oping rapidly. DESY’s PETRA III synchrotron in Germany accelerated its first beams for the production of X-ray light and SLAC’s Linac Coherent Light Source switched on as the world’s first X-ray laser with such high-energy X-rays in such short, bright pulses.

With the new funding, a whole catalog of experiments at the energy, intensity, and cosmic frontiers has renewed vigor. It is incumbent on the particle and accelerator physics communities to demonstrate that they are investing their increased funds for the benefit of both science and society.David Harris, Editor-in-chief

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commentary: pier oddone

Bosons and grocery bagsIn a March 1 Op-Ed piece in the New London Day, former Connecticut Congressman Bob Simmons raised concerns about provisions of the American Recovery and Reinvestment Act, the so-called stimulus bill.

“How did Congress conclude,” Mr. Simmons asked, “that spending hundreds of billions of our tax dollars on thousands of pet projects will stimulate our consumer economy? How much stimulus will result from funding a small group of physicists working at the Fermi National Accelerator Laboratory outside Chicago? They are racing to find evidence of a hypothetical particle called the Higgs boson before a com-peting team in Switzerland does—if they get some ‘stimulus’ money…Can we buy another bag of groceries, pay the mortgage or reduce accu-mulating bills if a handful of scientists in Chicago are able to prove the existence of something no one has ever seen?”

It would be tempting to dismiss Mr. Simmons’s concerns. Like most of our fellow citizens, he may not have had the opportunity to trace the connection between basic science and our global economic competitiveness. After all, quarks and leptons don’t bring to mind immediate technological breakthroughs and consumer prod-ucts, even though they are the fundamental blocks that build everything around us. And most people, even when they come into contact with accelerators such as those used in medical applications, don’t necessarily recognize them as by-products of the particle physics research that studies nature at a fundamental level.

So when questions arise about how the Higgs boson connects to buying another bag of groceries, we need to pay attention, because our fellow tax-paying citizens are the ones who pay the bills for US particle physics. They have a right to know what they are getting.

Because the connection between particles and payrolls is not obvious to most Americans, we have a special responsibility to demonstrate how high-energy physics research does help fill grocery bags and pay mortgages, not just by pro-viding short-term relief in a time of economic crisis but by creating the scientific infrastructure that will lead to long-term economic strength.

We should do this in several ways. We can show how the Recovery Act funding that we invest in scientific infrastructure at our labora-tories and universities creates immediate jobs for engineers, construction workers, and others in our communities. We can show how it affects the bottom lines—and the payrolls—of high-technology manufacturing firms that build the components for our experiments. We need to be transparent in accounting for the ways we use the funding we receive, and we need to tell the human story of the people who benefit. We can also describe the educational and research opportunities that these investments create, awakening our youngsters’ interest in pursuing scientific and technical careers.

We can also strengthen the effort, in partner-ship with the Department of Energy’s Office of High Energy Physics, to go beyond anecdotal evidence and systematically characterize and document the long-term economic benefits of high-energy physics research. The transformative contributions of particle physics to medicine, industry, and communication are a much-too-well-kept secret. We need to communicate better. A DOE-sponsored conference later this year will focus attention on the tangible economic bene-fits of accelerator-based physics research, both historically and in the future. Through this and other efforts we must demonstrate to our fellow citizens that investing in particles means investing in the strength of our scientific enter-prise and the strength, competitiveness, and well-being of our nation.

Pier Oddone is director of the Department of Energy’s Fermi National Accelerator Laboratory.

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signal to background

The real world of Angels & Demons; CMS digs Roman history; sand and silence

in Morocco; carpenters carve an ATLAS; battle of the buzzer at SLAC; what’s

in your office?

Physics lessons from Angels & DemonsReyna Pratt spends her days preparing high school students in Virginia for an increasingly competitive world. They learn biology, algebra, English composition, world history, and world cultures.

“I would love to teach my stu-dents about nuclear and particle physics,” says Pratt, a former theoretical nuclear physicist. “There’s just no time in the curriculum and schedule.”

Now, thanks to Angels & Demons, the big-screen adapta-tion of Dan Brown’s best-selling novel, her students and many others will get a glimpse at those scientific worlds, wrapped in Hollywood glitz and action.

The private girls’ school where she teaches is one of about 50 locations in the United States, 10 in Canada, and several in Europe and Asia scheduled to offer lectures explaining the science behind the film, its factual inaccuracies, and what high-energy physics

research can do for the world. “When I saw this opportunity,”

Pratt says, “I snagged it!”The film, which stars Tom

Hanks, is a detective story about an ancient secret society that tries to destroy the Vatican with a bomb made of antimatter stolen from a particle physics laboratory. Parts of the movie were filmed at CERN’s Large Hadron Collider, the world’s largest and most complex sci-entific venture.

In reality, antimatter would be useless as a bomb or energy source; it’s too hard to produce and store. The book misrepresents the production and storage of antimatter at CERN and portrays the European laboratory as more opulent than it really is.

Nonetheless, dozens of sci-entists are seizing on the film as a way to convey the truth about particle physics, using lecture materials prepared by CERN and Fermilab—the only other place in the world that produces and stores significant

numbers of antimatter particles.One of those volunteer lec-

turers is David Goldstein, a physicist studying acoustics at the Naval Research Laboratory.

“If I can contribute to inspiring someone,” he says, “or clear up some misunderstanding, or answer some questions in a way that someone might not otherwise have access to, then so much the better.”

Find lectures near your town at www.uslhc.us/Angels_Demons.Tona Kunz

TM & © 2009 Columbia Pictures Industries, Inc. All rights reserved.

location2103 CHAMBERLIN HALL

DatE & tiMEMAY 4, 2009, 7:30PM

titlEANGELS & DEMONS OF THE CERN LARGE HADRON COLLIDER

spEakErPROFESSOR WESLEY SMITHFOR MORE INFORMATIONVISIT WWW.PHYSICS.WISC.EDU/AAD/

TICKETS WWW.PHYSICS.WISC.EDU/AAD/TIX.PHP

Tom Hanks, Ayelet Zurer and Ron Howard at CERN to promote the movie Angels & Demons. Photo: CERN

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An LHC detector’s old Roman roots Particle physi-cists probe uncharted terri-tory for rem-nants of the early universe.

But that is supposed to occur after their experiments turn on.

In the case of the Compact Muon Solenoid experiment at CERN’s Large Hadron Collider, the discovery of ancient relics began when workers started digging a cavern 100 meters deep to house the 12,500-metric-ton detector.

“The first thing we found was the last thing you would ever want in a construction site—a Roman farm from the fourth century AD,” says Lyn Evans, LHC project leader.

Fortunately, the farm’s villa sat off to the side of the detector shaft and building footprint, allowing CMS crews to continue work while archeologists toiled nearby for nearly two years. During lunch breaks, workers on the CMS shaft wandered over to watch pots, coins, and stone walls emerge from the dirt.

“We had big earth movers, and they had tooth brushes,” says John Osborne, project manager for CMS civil engineering. “It was quite interesting to see the difference in excavation.”

Eventually, all but the farm’s stone walls were removed and sent to a museum in France.

The walls aligned perfectly with modern-day farm bound-aries. Unfortunately, they also sat where the innards of the CMS detector hall were to rest. So workers carefully covered the ruins with layers of blankets, sand, gravel, and rock.

“They are buried again,” Osborne says. “But they are pro-tected so archeologists could return to excavate in the future.”

The CMS detector sits in the town of Cessy in eastern France, an area where the Romans battled the Gauls in the third

century. Later, between 50 and 45 BC, Julius Caesar founded a Roman colony near the pres-ent town of Saint-Genis-Pouilly, whose boundaries encompass a large portion of CERN. The ruins of Roman villas, as well as coins, medals, silverware, jewelry, and graves from that period, have been found in the village, according to the tourism office.

Among the most notable things recovered in the CMS dig are coins minted in three areas, including sites near Rome and London.

“This proves the United Kingdom, at least during the fourth century, was part of a single European currency,” Evans jokes. Tona Kunz

ATLAS shrunkCarpenters working at particle physics labs are used to jobs their colleagues in private indus-try wouldn’t dream of tackling.

But a request to build a wooden replica of the world’s largest particle detector took even the carpenters at the German laboratory DESY by surprise.

Scientists asked them to build a model of the 7000-metric-ton ATLAS detector from CERN’s Large Hadron Collider at 1/25th actual size—two meters wide and one meter in diameter.

The intricate work took seven months.

To fit tools, paint, and their hands into the model, the crew had to assemble the model from the innermost layer outward. “Sometimes we wished we could just weld things together as though it were the real thing,” says head carpenter Werner Biegger.

The team of five had to work out a complicated choreography of tasks to make sure every-thing could be reached and painted in just the right order. And that’s not just one coat of paint: “Foundation, priming, more foundation, sanding down,

first coat, sanding down, second coat, then finishing layer,” Biegger recites.

In the finished product, bright-blue muon chambers sur-round the ATLAS detector like the planks of a wine barrel. Six aluminum magnet coils curve around the inner subdetec-tors, and a plastic workman bal-ances on the outer beam pipe. The coil and the toy are the only non-wooden parts.

“We wanted to make every-thing as realistic as possible,” Biegger says. “That’s why we chose aluminum for the coils; no lacquer on wood could do that job.”

The model made its public debut in October and is now touring the country, showcasing the beauty of ATLAS and helping scientists explain how it works. Requests for other models are already trickling in.Barbara Warmbein

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A desert quest for no-cell-phone zoneIt seemed like a mirage: A shep-herd holding a silver tea service crossing barren desert to quench the thirst of strangers.

In their search for a quiet place to build a telescope that will make a 3D map of the universe, Fermilab’s Ralph Pasquinelli and Dave McGinnis had entered a different world.

“That area made the Mars landscape look hospitable,” McGinnis says.

The two engineers from Illinois had traveled over the Atlas Mountains and through roadless areas of the Sahara desert to the most remote region of Morocco. They endured rain, snow, and blowing sand, and sometimes had to scout on foot for passages suitable for their four-wheel-drive vehicle loaded with 300 pounds of test equipment.

The inhabitants of the area herd goats and sheep. There are no villages, government offices, electricity, or running water. “These people are living the way they did for hundreds of years,” Pasquinelli says.

While local people do have cell phones, signal towers are scarce, making this a perfect location for a radio telescope that needs to operate free from interference by radio waves.

The proposed telescope project would use a new strategy to measure the collective emissions of hydrogen in many galaxies at once with unprece-dented precision and efficiency. The resulting map should reveal the frozen ripples of cos-mic sound waves whose travels through the early universe were shaped by dark energy.

“By measuring the density fluctuations of the universe in 3D, we can hope to understand more about dark energy,” McGinnis says. Scientists believe dark energy could explain why the universe is expanding today.

The proposed $20 million to $25 million telescope could be built by a collaboration between Fermilab, Carnegie Mellon University, CEA-Saclay

and Orsay labs in France, and Morocco’s Al Akhawayan University, which would run the telescope. Proponents hope to get funding from Arab states.

“It is really exciting for Morocco, a developing country, to have this scientific instrument in their back yard,” Pasquinelli says. “This would really help to bolster their economy,” bringing in roads, water, and other infra-structure and perhaps attract-ing businesses.

The telescope might even sit on the grazing land of the shepherd who walked three kilometers to their work site to greet them with tea and, according to ancient custom, offer his one-room home for breakfast and lodging.Rhianna Wisniewski

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Top: Scientists and team members scouting locations in Morocco take advantage of a local shepherd’s hospitality. Right: Fermilab engineers set up equipment to search for radio wave signals that could interfere with the proposed experiment. Left: Engineers camp out in the Moroccan desert to search for radio wave signals.













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Top: Scientists and team members scouting locations in Morocco take advantage of a local shepherd’s hospitality. Right: Engineers set up equipment to search for radio wave signals that could interfere with the proposed experiment. Left: Engineers camp out in the Moroccan desert to search for radio wave signals.

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Bowling for scienceOn what should be a sleepy Sat-urday at SLAC National Accelerator Laboratory, the air is buzzing. It’s the SLAC Department of Energy Regional Science Bowl, and in conference rooms and auditoriums, 24 teams of four race to hit buzzers, quiz-show style, in response to rapid-fire questions about everything from gravitational lensing to butterfly hormones.

After six hours of increasingly diabolical trivia, Homestead High School claimed its third con-secutive victory, earning an all-expenses-paid trip to the Washington, DC, Nationals in late April. There the team would vie with 67 other regional champs for a trip to Australia to attend the International Science School,

a $1000 grant for their school’s science

program, and

a really, really big trophy. “I feel like I’m going to wake

up any second now,” said Homestead senior Jan Wu. “It’s been in my head for a while, but I’m still like, ‘Oh my gosh, we just won!’”

Students train for the event with an intensity usually reserved for football—poring over scientific tomes, flipping through flashcards, and scrim-maging other teams.

“These kids know things about every branch of science,” said moderator Travis Brooks, who runs the SPIRES database at SLAC. “Even very good scien-tists have no chance at a lot of these questions, because they know just one field very well.”

This is Brooks’ fourth year joining the 50 or so SLAC staff-ers volunteering as moderators, scorekeepers, and timekeepers. He said he has a personal reason to take his role seriously.

“In high school, I got cheated once during this type of game,”

Brooks said. “They asked me for a five-letter word meaning ‘money taken illegally,’ and I said ‘bribe.’ They said it was wrong—they wanted ‘graft.’” The question eliminated Brooks’s team from the semi-finals, robbing them of a chance at scholarship money.

At the end of the long day, enthusiasm was still high, even among those who didn’t receive a medal from special guest Martin Perl. Homestead High’s Lisa Yao, a senior planning to major in biology, was in the throng that crowded the podium to snag a photo with the SLAC Nobel laureate. Yao said she enjoyed Perl’s speech, in which he outlined the advances he hopes to see this next genera-tion of scientists achieve. “It just shows how many doors are open for us right now,” Yao said. “That was really inspiring.”Lauren Schenkman

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An office serves as a home away from home. You personalize it. Make it comfortable. Surround yourself with keepsakes from your family, friends, and career. In a physics lab, these office mementos often go far beyond the usual logo-emblazoned coffee mug or plaque.

For instance, John Cooper, project manager for Fermilab’s NOνA neutrino experiment, keeps eight tubes of grey-and-pink granite on a specially made wooden holder. The rock cores came from two sites that competed to host the experiment’s underground far-detector hall—including the winner, Ash River in Minnesota.

Do you keep remembrances from experiments in your office? Something that reminds you of the camaraderie of a collaboration or the success of a project?

Send symmetry a photo and 100 words describing the memento, its sentimental meaning, and its origin. We’ll run the best of the submissions in a future issue.

Call for mementos!

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Bowling for scienceOn what should be a sleepy Sat-urday at SLAC National Accelerator Laboratory, the air is buzzing. It’s the SLAC Department of Energy Regional Science Bowl, and in conference rooms and auditoriums, 24 teams of four race to hit buzzers, quiz-show style, in response to rapid-fire questions about everything from gravitational lensing to butterfly hormones.

After six hours of increasingly diabolical trivia, Homestead High School claimed its third con-secutive victory, earning an all-expenses-paid trip to the Washington, DC, Nationals in late April. There the team would vie with 67 other regional champs for a trip to Australia to attend the International Science School,

a $1000 grant for their school’s science

program, and

a really, really big trophy. “I feel like I’m going to wake

up any second now,” said Homestead senior Jan Wu. “It’s been in my head for a while, but I’m still like, ‘Oh my gosh, we just won!’”

Students train for the event with an intensity usually reserved for football—poring over scientific tomes, flipping through flashcards, and scrim-maging other teams.

“These kids know things about every branch of science,” said moderator Travis Brooks, who runs the SPIRES database at SLAC. “Even very good scien-tists have no chance at a lot of these questions, because they know just one field very well.”

This is Brooks’ fourth year joining the 50 or so SLAC staff-ers volunteering as moderators, scorekeepers, and timekeepers. He said he has a personal reason to take his role seriously.

“In high school, I got cheated once during this type of game,”

Brooks said. “They asked me for a five-letter word meaning ‘money taken illegally,’ and I said ‘bribe.’ They said it was wrong—they wanted ‘graft.’” The question eliminated Brooks’s team from the semi-finals, robbing them of a chance at scholarship money.

At the end of the long day, enthusiasm was still high, even among those who didn’t receive a medal from special guest Martin Perl. Homestead High’s Lisa Yao, a senior planning to major in biology, was in the throng that crowded the podium to snag a photo with the SLAC Nobel laureate. Yao said she enjoyed Perl’s speech, in which he outlined the advances he hopes to see this next genera-tion of scientists achieve. “It just shows how many doors are open for us right now,” Yao said. “That was really inspiring.”Lauren Schenkman

Pho

to: L

aure

n S

chen

kman

, SLA

C

An office serves as a home away from home. You personalize it. Make it comfortable. Surround yourself with keepsakes from your family, friends, and career. In a physics lab, these office mementos often go far beyond the usual logo-emblazoned coffee mug or plaque.

For instance, John Cooper, project manager for Fermilab’s NOνA neutrino experiment, keeps eight tubes of grey-and-pink granite on a specially made wooden holder. The rock cores came from two sites that competed to host the experiment’s underground far-detector hall—including the winner, Ash River in Minnesota.

Do you keep remembrances from experiments in your office? Something that reminds you of the camaraderie of a collaboration or the success of a project?

Send symmetry a photo and 100 words describing the memento, its sentimental meaning, and its origin. We’ll run the best of the submissions in a future issue. Send email to [email protected]

Call for mementos!

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symmetrybreaking

Highlights from our blog

World’s first hard- X-ray laser switches onApril 21, 2009

In a stunning piece of engineer-ing, the Linac Coherent Light Source at SLAC generated X-ray laser light immediately after being switched on. It is the first time that an X-ray laser has operated at such short wave-lengths, with such brightness and short pulses. The laser paves the path to a new way of looking at not only the structure of matter but also its dynamics.

A story of the people who shaped FermilabApril 21, 2009

With the release of a new book, Fermilab: Physics, the Frontier and Megascience, three women who have spent years at the flagship laboratory for American high-energy particle physics provide a historical view of how big science happens. They also reveal some little-known facts surrounding the “laboratory on the prairie.”

Manhunt in the DESY storage hallsApril 15, 2009

Chasing criminals has been added to the training program on the DESY campus in Hamburg. To be fair, though, the trainees from the Hamburg police department have four legs and sharp teeth. The training was child’s play for cold-nosed professionals like Pollo, Carlos, Bonsai, and Butch.

The Big Bang Theory comedy gets Nobel laureateApril 14, 2009

So much for the stereotype that seriously smart people can’t have a sense of humor. The acclaimed CBS prime-time comedy The Big Bang Theory had a guest appearance by a Nobel laureate on March 9— George Smoot, professor of physics at the University of California, Berkeley; research physicist at Lawrence Berkeley National Laboratory; and a confessed fan of the show.

High-energy physics lab takes on high-energy weatherApril 13, 2009

Calling all weather buffs, storm chasers, and would-be tornado spotters. It’s time for the 29th annual Tom Skilling Tornado Seminar at Fermi National Accelerator Laboratory in Batavia, Illinois.

Devastating quake jolts Gran Sasso regionApril 6, 2009

The area of central Italy struck by a magnitude 6.3 earthquake this morning is home to Gran Sasso National Laboratory. The INFN particle physics lab is located in the heart of a moun-tain about half an hour’s drive from the hard-hit medieval city of L’Aquila. The preliminary word this morning from laboratory spokeswoman Roberta Antolini was that the laboratory appeared to be undamaged and most laboratory workers safe.

New video of the frenetically twinkling gamma-ray skyApril 6, 2009

The gamma-ray sky is intensely frenetic, twinkling with aban-don. And now, thanks to a series of time-lapse movies released Friday by NASA, the US Department of Energy, and the Fermi Gamma-ray Space Telescope’s Large Area Telescope collaboration, you too can enjoy the frenzy.

MINERνA opens eyes to neutrino dataApril 3, 2009

A new neutrino detector just got its first glimpse at how the elu-sive particles interact. The first portion of Fermilab’s MINERνA detector observed its first events from the NuMI neutrino beam Wednesday night.

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Read the full text of these stories and more at www.symmetrymagazine.org/breaking

Quantum Diaries is backApril 3, 2009

Are physicists’ models being held culpable in the financial meltdown? Do physicists appre-ciate music for its mathematical appeal? How will the International Linear Collider complement the Large Hadron Collider? These topics and more are under discussion in the blogs of Quantum Diaries, freshly launched yesterday with a new set of visiting contributors from around the globe and across the world of particle physics.

Particles attempt lab takeoverApril 1, 2009

Fermilab temporarily halted Tevatron operations early on Tuesday morning when a batch of particles broke free from the accelerator and staged a coup at the laboratory.

Single top quark in the palm of your handMarch 24, 2009

There’s more than one way to find a single top quark. You can spend more than a decade combing through data from a particle collider, or you can commission one from Julie Peasley, a soft-sculpture artist in Los Angeles.

Particle oddball surprises physicistsMarch 18, 2009

Scientists of Fermilab’s CDF experiment have found evidence of an unexpected particle whose curious characteristics may reveal new ways that quarks can combine to form matter. The physicists have called the particle Y(4140), based on how it is produced and how much it weighs. It joins a handful of X and Y particles dis-covered at other laboratories, all of which flout nature’s known rules for fitting quarks and antiquarks together.

Higgs territory continues to shrinkMarch 13, 2009

Fermilab’s CDF and DZero experiments have excluded a significant fraction of the allowed Higgs mass range established by earlier measurements. But they have not yet caught a glimpse of the elusive particle.

Fermilab collider experiments discover rare single top quarkMarch 9, 2009

Scientists at Fermilab have observed a new subatomic pro-cess. In particle collisions produced by the Tevatron col-lider, two teams of scientists found single top quarks. The discovery has significance for the ongoing search for the Higgs particle.

Higgs turning up everywhere, this time in paintMarch 4, 2009

Tales of Higgs sightings (in the form of the man) are turn-ing up everywhere, but now he has appeared in the form of a painting by one of Scotland’s best-known artists, Ken Currie, in the School of Informatics at the University of Edinburgh.

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A NEW LEADER FOR CERN By Katie Yurkewicz

Photos: CERN

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In his first few months on the job, CERN Director-General Rolf-Dieter Heuer opens new lines of communication, oversees repairs to the Large Hadron Collider, and promotes a worldwide strategy for particle physics based on a strong mix of global, regional, and national projects.On January 1, German particle physicist Rolf-Dieter Heuer began a five-year

term as the director-general of CERN, the European Organization for

Nuclear Research. Heuer takes the helm at a singularly challenging time for

the European particle physics laboratory. He faces the immediate tasks of

repairing and restarting the Large Hadron Collider and rebuilding the laboratory’s

aging infrastructure, all in the framework of a worldwide financial crisis. He

is also likely to guide the laboratory through the years in which a decision will

be made on the next big particle physics project after the LHC. Alongside

all of this, he hopes to advance an ambitious agenda to reshape the future of

particle physics research—not just at CERN, but worldwide.

Heuer is not a stranger to CERN or to the complexities of the international

particle physics community. He was on the staff of the laboratory for 14

years, ascending to the post of spokesperson for the OPAL experiment at

CERN’s Large Electron-Positron collider. In 1998 he left CERN for the

University of Hamburg, and in 2004 became research director for particle

physics and particle astrophysics at the German laboratory DESY. There

he shaped DESY’s—and the country’s—role in global particle physics, in the

process setting the stage for many of the ideas he is now pushing forward at

CERN in the areas of communication, cooperation, expansion, and innovation.

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Breaking newsWhen asked to name the biggest change he has introduced in his first months at CERN, Heuer immediately identifies his policy of clear and fast communication to CERN’s staff and the users of its experimental facilities. Within weeks of his arrival, CERN’s weekly bulletin began to publish LHC repair updates, and Heuer’s office began emailing major news to staff—even late on Friday evenings, when needed. Following in the foot-steps of many a chief executive, Heuer has also remarked on his hope of reducing the distance between the CERN management and staff as much as possible, by showing his presence around the laboratory.

Clear and open communication with govern-ments, laboratories, and institutes around the world is also critical for a laboratory that is funded and run by 20 member countries, has agreements with more than 40 others, and counts 111 nationali-ties among its staff and users. To provide a conduit for such communication, and to strengthen the laboratory’s relationship with other particle physics institutes, Heuer established a new External Relations unit at CERN. This unit will also play a key role in Heuer’s bolder, and potentially more controversial, ideas for the future of the laboratory.

A broad visionHeuer’s vision for CERN is to reshape it from a European laboratory toward a truly global labora-tory, building on a trend that started long before his appointment.

The experiments at the Large Hadron Collider, soon to become the world’s highest-energy particle accelerator, now boast more than 7000 scientist collaborators—roughly half the world’s particle physicists. In 2006 the CERN Council, the laboratory’s governing body, took on the responsi-bility of leading European particle physics strategy. And in December 2008 the Council approved the creation of a study group to examine the geo-graphical and scientific enlargement of CERN.

Heuer is quick to note that the laboratory won’t be making any radical changes in scientific direction. “CERN’s raison d’etre is accelerator-based particle physics,” he explains. “This is the strength of CERN, and this is where we have world experts. I see scientific enlargement, in a very careful way, mainly in the direction of particle astrophysics.” A field at the intersection of particle physics, astronomy, and cosmology, particle astro-physics is the study of elementary particles that originate in space, and would be the most natural extension for CERN.

Expansion plansA major particle astrophysics program is not imme-diately in the works, however. First steps toward expansion could include encouraging CERN theo-rists to work in the areas of theoretical particle

astrophysics as well as particle physics, or offer-ing CERN’s expertise with coordinating large, multinational projects to particle astrophysics projects that are themselves becoming larger and more international.

CERN is also making plans to expand its parti-cle physics program. The lab will create a new center for the analysis and interpretation of LHC data and hold a workshop in May to gather new ideas for CERN’s fixed-target experimental pro-gram, in which particle beams slam into stationary targets rather than colliding head-on with other beams.

In the area of geographic expansion, Heuer says nothing is off the table—which has other regions of the particle physics world following the study group’s work very carefully. In his first address to the CERN community, he stated that CERN’s founding Convention says nothing about membership being restricted to European coun-tries, leaving the door open to the possibility of more CERN members from other world regions. Other options for geographic expansion could include additional CERN sites or additional types of CERN partnerships.

“One could imagine all kinds of different models, and it will be the challenge for the CERN Council to come up with something which is interesting enough for CERN but also for the other regions,” says Heuer. “We definitely need to get input from the other regions into the process.”

Building a global strategyHeuer has plans not only for the future of CERN, but also for the future of worldwide particle phys-ics. In a climate of increasing financial pressure on particle physics and greater overlap between parti-cle physics and related fields, he is convinced that all the countries involved in this research—and all the agencies that fund it—need to come together to plan a concrete strategy.

The response from colleagues “has been essentially only positive,” he says. “I think they all appreciate the statement that we should be open and make the process more global. Now we have to see how to do it. That’s really the tricky thing.”

The new strategy would go beyond previous efforts to plan cooperatively, with a goal of main-taining particle physics expertise and ensuring long-term support for particle physics in all world regions.

“I am personally convinced that particle physics needs national, regional, and global projects,” says Heuer. “We cannot survive with only a global project; I think it’s nonsense. We have to have other projects which complement the physics, but we don’t need the same proj-ect in all countries or all regions. We need to somehow find the best distribution of regional projects. I don’t exclude that one does similar

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things, but we have to do it consciously, some-how, together.”

The first steps toward implementing this vision were taken at the February meeting of the International Committee for Future Accelerators, where Heuer met informally with Fermilab Director Pier Oddone and Atsuto Suzuki, director-general of Japan’s KEK laboratory.

“I’m delighted Rolf is advocating an approach that coordinates the programs in the most effective way between the three regions, recognizing that for any one region to remain strong in the long term, all regions must be strong,” says Oddone.

The LHC is becoming the first truly global project, and a decision on its successor is likely within five years. If the next big particle physics project is also sited in Europe, what will happen to expertise in other regions?

Heuer notes that this is difficult to judge, but points to astronomy as an example.

“You do the work at home, but your telescope is where you have the best view of the sky, be it in Namibia, Argentina, or Chile,” he explains. “Nonetheless people participate. Why shouldn’t this be possible also for particle physics? Only because we are used to having our machines in our backyards. It means rethinking.”

Driving innovationHeuer comes to CERN with grand goals for the laboratory and for his field, but will have to pursue those goals in the framework of a global economic meltdown. “Surviving the financial crisis with a budget that is adequate for our science and for the survival of CERN” is the biggest challenge he names for the coming years.

CERN will dodge the bullet for 2009, as mem-ber countries’ financial contributions were agreed upon before the crisis began, but may be hit in 2010. Heuer pins his hopes for increasing funding on identifying good physics projects and improv-ing CERN’s transfer of knowledge and technology to its member countries and the rest of the world. CERN’s Knowledge and Technology Transfer group—just Technology Transfer before his arrival—has an increased profile and is charged with first measuring, then increasing and better communicating such transfers.

“We have to somehow quantify, for example, the knowledge transfer, which is very difficult,” he acknowledges. “We can also try to have more proj-ects with applied research. I don’t want to move CERN into an applied physics lab, but I think we can do a little bit more in applying what we develop. People are very motivated to do that; they just need a little more seed resources.”

Heuer adds that science remains the driver of innovation, and that he hopes governments around the world will recognize that fact and continue to invest in basic research: “Maybe the crisis opens their eyes and they realize that the future is shaped by research. And CERN is a fantastic place for research, not only in particle physics but also in technology. If they realize this then hope-fully they realize that we need our budget.”

When asked to picture CERN in 2013, at the end of his five-year term, Heuer concludes, “I would hope that the LHC has delivered first dis-coveries that at least give us the path at the energy frontier we have to take, and that we have taken the first few steps toward a global particle physics strategy.”

The Globe of Science and Innovation is the departure point for tours of CERN. A gift from the Swiss gov-ernment, it’s made entirely of wood.

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Illustrations: Sandbox Studio

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Illustrations: Sandbox Studio

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CHINA

American scientists are flocking to the Beijing Electron Positron Collider, whose recent upgrades make it the premier place to study charm quarks and their kin.By Kelen Tuttle

Chasing charm in

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The flight plan of today’s particle physicist can be a dizzying thing. Like migratory creatures, research-ers circle the globe in search of the best data, working on one experiment for several years and then moving on to the next, all in the hope of answering fundamental questions about the way the world works.

One of particle physics’ most recent migrations involves researchers from the United States. For several years, scientists with Cornell University’s CLEO-c experiment in New York studied charm quarks produced in collisions of electrons with positrons. Yet just as they began to find intriguing hints of the unexpected, CLEO-c reached the end of its allotted funding and shut down.

Now the researchers are refocusing their work on the Beijing Electron Spectrometer, located at China’s Beijing Electron Positron Collider. When the machine ramps up to full strength after a recent upgrade, it will be the world’s premier instru-ment for studying particles that contain a charm quark, as well as for many other types of physics.

This is not the first time Americans have migrated to Beijing collider experiments. They have come and gone over the facility’s two decades, although in recent years it was more of the latter, with all of the American collabora-tors—except a core group from the University of Hawaii—leaving Beijing to join experiments in the United States. But recently, as US electron–positron colliders shut down, the Americans have returned.

“This was a good deal for all,” says University of Minnesota Professor Ron Poling, whose group was one of the first in this new wave of American collaborators. “Beijing had an upgraded acceler-ator and a new detector, and we had physics we wanted to do on just such a machine—but nowhere to do it. We couldn’t have made this transition more seamless if we had planned it from the beginning.”

Cranking out the charmAbout 200 miles northwest of the buzz of New York City, the CLEO-c detector operated at a low hum from 2005 to 2008. The machine’s energy was tuned to produce particles containing charm quarks against a limited background of other pro-cesses, allowing for very precise studies of charm quark decays. These decays offer researchers a means to test the Standard Model of particle physics, which describes the interaction of all visible matter in the universe. The Standard Model has been validated in many experiments; by look-ing at exceedingly precise data like that from CLEO-c, researchers check whether the model holds true there, too.

Charm factories like those at Cornell and Beijing tend not to make front-page discoveries as often as their high-energy cousins, such as Fermilab’s Tevatron. Charm factories don’t operate at energies high enough to produce never-before-seen, super-heavy particles. But despite their lower profiles, charm factories do groundbreaking work.

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By taking very precise measurements, charm fac-tories can very accurately test theories, see the minuscule secondary effects of new physics, and even discover new low-mass particles.

“If a rare process shows up at an abnormally large rate or you see something forbidden by the Standard Model, it’s evidence of new physics,” says University of Minnesota Professor Dan Cronin- Hennessy, who worked on the CLEO experiment for more than a decade.

One of the ways that researchers at CLEO-c tested the Standard Model and searched for this new physics was by observing decays of mesons containing charm quarks.

Hint of new physicsMesons are subatomic particles that each contain a quark, an antiquark, and some gluons, the ele-mentary particles that help bind them together. The inside of a meson is a tumultuous place. Quarks constantly exchange gluons and those gluons constantly exchange other gluons. To make things even more complicated, the laws of quantum mechanics govern this swarm of parti-cles, which means not only that researchers can never know precisely where a particle is located, but also that particles in this dynamic mix appear and disappear in the blink of an eye.

Nonetheless, researchers strive to understand the world around them, right down to the chaos within the meson, and so have found a way to explain the interaction between quarks and gluons

using the theory of Quantum Chromodynamics, or QCD for short. QCD works well at high energies, but calculations of what exactly goes on at the lower energies at play within a meson are exceedingly complex—so complex, in fact, that even the world’s most powerful computers find it impossible to make these calculations with a high degree of precision.

So researchers simplify those dynamics with a method called lattice quantum chromodynamics, or LQCD. It envisions particles interacting not within space and time as we experience them, but in finite increments—as if the particles existed only on the vertices of a three-dimensional grid, with time ticking forward in discrete clicks. By running computer simulations of this grid-world, physicists can apply QCD to lower-energy situa-tions and make increasingly precise predictions.

At CLEO-c, researchers did find a small dis-agreement between those predictions and the observed decay of Ds mesons. Was this proof of new physics? A flaw in the LQCD simulations? Or nothing more than a blip in the data?

A timely switchBefore they could answer these questions, funding for CLEO-c dried up. The machine stopped taking data in the spring of 2008.

“CLEO-c was very successful, but we didn’t get the accelerator performance that we had hoped, and our goals are not yet fully met,” says University of Rochester Professor Ed Thorndike, who has

At the Beijing Electron Positron Collider, the real action takes place in shielded tunnels. The 200-meter-long linear accelerator, beneath the long, skinny building on the right, accelerates electrons and positrons and injects them into an underground storage ring, left, that is 240 meters around. The Beijing Spectrometer detector records those collisions, which offer clues to the nature of subatomic processes and particles, including the charm quark and its kin.

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By taking very precise measurements, charm fac-tories can very accurately test theories, see the minuscule secondary effects of new physics, and even discover new low-mass particles.

“If a rare process shows up at an abnormally large rate or you see something forbidden by the Standard Model, it’s evidence of new physics,” says University of Minnesota Professor Dan Cronin- Hennessy, who worked on the CLEO experiment for more than a decade.

One of the ways that researchers at CLEO-c tested the Standard Model and searched for this new physics was by observing decays of mesons containing charm quarks.

Hint of new physicsMesons are subatomic particles that each contain a quark, an antiquark, and some gluons, the ele-mentary particles that help bind them together. The inside of a meson is a tumultuous place. Quarks constantly exchange gluons and those gluons constantly exchange other gluons. To make things even more complicated, the laws of quantum mechanics govern this swarm of parti-cles, which means not only that researchers can never know precisely where a particle is located, but also that particles in this dynamic mix appear and disappear in the blink of an eye.

Nonetheless, researchers strive to understand the world around them, right down to the chaos within the meson, and so have found a way to explain the interaction between quarks and gluons

using the theory of Quantum Chromodynamics, or QCD for short. QCD works well at high energies, but calculations of what exactly goes on at the lower energies at play within a meson are exceedingly complex—so complex, in fact, that even the world’s most powerful computers find it impossible to make these calculations with a high degree of precision.

So researchers simplify those dynamics with a method called lattice quantum chromodynamics, or LQCD. It envisions particles interacting not within space and time as we experience them, but in finite increments—as if the particles existed only on the vertices of a three-dimensional grid, with time ticking forward in discrete clicks. By running computer simulations of this grid-world, physicists can apply QCD to lower-energy situa-tions and make increasingly precise predictions.

At CLEO-c, researchers did find a small dis-agreement between those predictions and the observed decay of Ds mesons. Was this proof of new physics? A flaw in the LQCD simulations? Or nothing more than a blip in the data?

A timely switchBefore they could answer these questions, funding for CLEO-c dried up. The machine stopped taking data in the spring of 2008.

“CLEO-c was very successful, but we didn’t get the accelerator performance that we had hoped, and our goals are not yet fully met,” says University of Rochester Professor Ed Thorndike, who has

At the Beijing Electron Positron Collider, the real action takes place in shielded tunnels. The 200-meter-long linear accelerator, beneath the long, skinny building on the right, accelerates electrons and positrons and injects them into an underground storage ring, left, that is 240 meters around. The Beijing Electron Spectrometer detector records those collisions, which offer clues to the nature of subatomic processes and particles, including the charm quark and its kin.

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worked on data from a series of collider experi-ments at Cornell for more than two decades. “We very much want to repeat these measurements at another machine to see what’s going on.”

China’s accelerator offers just such an opportunity.

Just about the time that CLEO-c started run-ning, the Chinese Institute of High Energy Physics started major improvements to the Beijing collider and began to construct a new Beijing Spectrometer detector, BES-III.

“When we started the upgrade construction, we were hoping that more US groups would get involved,” Yifang Wang, spokesman for BES-III, says. “There’s a complementary function between BES-III work and CLEO-c work. It’s beneficial to the physics and to the community when we can collaborate in this way.”

Ten times more dataThe goal of the upgrade was to increase the detector’s sensitivity and the collider’s luminosity, a measure of the number of particles in each collision. To do this, the Chinese institute retained

the original accelerator tunnel and infrastruc-ture, but replaced nearly everything else. Instead of accelerating single electron and positron bunches inside one storage ring, the new machine accelerates 93 electron and 93 positron bunches at a time inside two storage rings. A pristine superconducting magnet, the first of its kind built in China, combines with the shiny new BES-III detector to more precisely measure particles’ energies and speeds. And an innovative calibra-tion system involving a diode laser built by the University of Hawaii ensures that the time-of-flight detector system, which identifies particles, is performing as designed. These and other improvements make collisions at the Beijing accel-erator the best in the world for studying physics in this energy region.

“BES has a long history of very important physics,” says University of Hawaii Professor Fred Harris, who served as co-spokesperson of BES-II and continues that role for BES-III. In its previous incarnations, the Beijing detector made ground-breaking precision measurements of the tau particle mass and the R value, which measures

The charm quark is one of 16 types of elementary particles observed by experimenters.

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the likelihood that electron–positron collisions will create particles made of quarks. The R value helped refine the prediction of the mass of the Higgs, the as-yet-unseen particle thought to lend elementary particles their mass.

With a design intensity 100 times that of the original Beijing Electron Positron Collider, Harris says, the upgraded accelerator “promises even more significant contributions.”

Once the upgraded machine reaches full luminosity—which should happen in two to three years—it will produce significantly more data of the type sought by the CLEO-c physicists. The new detector is noticeably more sensitive than BES-II and when commissioning is complete, will produce collisions at a rate more than 10 times higher than at CLEO-c, thanks in large part to the new storage rings. This increase in power and sensitivity should lead to a better understanding of the disagreement previously glimpsed at CLEO-c.

“With limited statistics, you can find a hint that maybe something is going on,” Thorndike says. “But with ten times more data you can see if it’s just a fluctuation or if it’s a real effect and you’ve found something exciting.”

Forging new partnershipsIn July 2008, just a few months after CLEO-c shut down, the new BES detector recorded a beam from the upgraded collider for the first time. The Americans were ready and waiting; with encour-agement from University of Hawaii researchers and BES management, the universities of Minnesota, Florida, and Rochester and Carnegie Mellon University had officially joined the collab-oration earlier that year.

The newcomers are now working to integrate themselves into the collaboration. For instance, the University of Minnesota repurposed a com-puting farm, originally built to run simulations for CLEO-c, to serve as a North American data hub for BES-III. Now the university will serve as a middleman, importing large chunks of data from Beijing and making it available to US researchers, who will analyze data with this same computing farm.

“Working remotely has always been difficult, but it’s getting easier,” Carnegie Mellon Professor Roy Briere says. “Spotty connections make trans-ferring data from China rather difficult; instead of every group trying to transfer the data and run the software individually, we do it in one centralized location.”

With the Beijing data, US scientists will dive back into much of the research they conducted at CLEO-c, searching for new physics and testing LQCD. If researchers confirm the earlier CLEO-c results that seemed to disagree with theory, theo-rists will have a lot of thinking to do; it would mean that either the LQCD calculations are flawed, or some sort of physics beyond the Standard Model

is at play. If, on the other hand, the LQCD calcula-tions prove accurate, researchers will know that they understand the intricacies of the chaos within the meson well enough to predict how it behaves.

“Understanding this is an essential ingredient for particle physics,” Poling says.

A multipurpose toolWhile testing the CLEO-c results is one of the major goals of the Americans who moved to Beijing to work with the new detector, it is not by any means the only physics that will be done there.

The upgraded Beijing collider operates in an exciting energy range called the tau/charm region. Here, electron–positron collisions are energetic enough to form the charm quarks that interest the CLEO-c researchers. But by changing the beam energy in this region, scientists can also produce very large numbers of J/psi particles as well as excited forms of J/psi called psi' and psi" (pronounced “psi prime” and “psi double prime”). By observing the decays of these particles, BES collaborators from around the world will continue their explorations of many unresolved topics in physics, including searches for gluons bound into a difficult-to-observe particle called a glue-ball—something predicted by QCD but not yet unambiguously seen. Researchers will also look for new physics within the decays of the J/psi, psi' and psi". And, as with charm quarks, they will use these three particles to test LQCD calculations.

Binding together this varied research is the desire to understand the minute workings of the physical universe and the knowledge that, as the years pass, fewer and fewer facilities around the world will offer researchers the opportunity to perform these studies.

“What’s nice is that you can do many types of physics at a single machine,” Cronin-Hennessy says. “We’re approaching this in different ways, but we have the same final goal: to understand the fundamental forces of nature.”

Right now, the Beijing accelerator is focused on churning out psi’ particles, and has already recorded the world’s largest sample of psi’ data ever produced at an electron–positron collider. Once researchers have tripled that data set, they plan to move on to other energy ranges and other particles. In two to three years, the collab-oration plans to begin producing the Ds mesons that will allow researchers to continue the research begun at CLEO-c.

“Thanks to the Chinese, we may be able to answer some of the most compelling questions in particle physics,” Poling says. “The Chinese have built it, and we have come.”

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In the swirling sea of thousands of people who contribute to a major particle physics experiment, how can a young physicist pop to the surface and get noticed? An international committee offers ideas.

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Physicists around the world know the name Timo Aaltonen.

The Finnish graduate student has yet to com-plete his PhD. But since April 2007, members of the Collider Detector at Fermilab, or CDF, collabo-ration have credited almost all of their publications to “T. Aaltonen et al.”

Particle physicists know that Aaltonen did not, in fact, write all of those papers. CDF publications list as authors every one of the collaboration members—all 602 of them—in alphabetical order. Before Aaltonen came along, the first author was “A. Abulencia.”

The author list does not distinguish between the senior scientists who come up with ideas, the hardware specialists who helped design and build the machine and the grad students who put in long hours analyzing results. Some of those on the list might not have even read the paper because they are busy working on some other part of the experiment.

“I don’t know anything about physics,” Aaltonen jokes when people recognize him. “My boss only took me into the group to get someone from Helsinki as a first author.” In fact, he studies b-jets in search of Higgs decays and spends most of his time processing raw data for physics groups in the collaboration.

In the early days of high-energy physics, researchers conducted experiments in small groups or even individually. Now they often work with much larger, more complex machines and detectors, in groups of collaborators that may number in the hundreds—or even thousands, in the case of the Large Hadron Collider, the 27-km particle accelerator situated at the border of Switzerland and France.

With the LHC experiments poised to produce papers that list as many as 3000 authors, a working group from the International Union of Pure and Applied Physics Commission on Particles and Fields has developed voluntary guidelines for crediting contributors fairly while maintaining the collaborative spirit.

The group called for collaborations to clarify their authorship rules and to find ways to publicly acknowledge the work of individual members through additional record-keeping or awards. It recommended they consider using two-tiered author lists to recognize those who made special contributions.

And it advised individuals to list on their cur-riculum vitae only the publications to which they made significant contributions.

The group does not expect current collabora-tions to adopt many of these recommendations, says current commission Chair Patty McBride of Fermilab’s computing division.

“It’s hard to impact a collaboration that’s been around for 10 years,” she says.

Instead, the group is more hopeful that

scientists will consult the report when crafting policies for future experiments.

The shiniest apple in a crate of orangesThe current, decades-old system of including every collaboration member as an author was designed to give individuals an incentive to contribute to every aspect of the experiment. It helps large groups of people who may never meet face-to-face to feel like a team, says David Saxon, spokes-man for the ZEUS collaboration in Hamburg.

“If you’re not going to drink a beer with some-body, you’re going to have to find other ways to promote cohesiveness in the collaboration,” he says.

But to find out how each person added to the collective effort, outsiders have few clues. Contributors’ names are buried in a list of authors that can run longer than the article itself.

Trends in university hiring have raised concern about the difficulty of standing out in such a large crowd.

Universities try to keep job candidate searches as narrow as possible, says Robert Wald, chair of the University of Chicago’s physics department. “It would be very hard to compare a high-energy physics collider experimentalist with a condensed matter experimentalist,” he says.

But some universities try to broaden their applicant pools, in part to reach larger numbers of women and members of minority groups, says Daniel Gauthier, chair of the physics department at Duke University.

Pitted against scientists in other disciplines for teaching positions, particle physicists find them-selves at a disadvantage, as scientists in other fields often work in smaller groups and are more likely to land spots on author lists a line or two long.

Lost in a sea of authors, a young experimental physicist seeking a position or tenure at a uni-versity may have trouble proving his or her worth, says Gregor Herten, a physicist at Freiburg University in Germany and former chair of the IUPAP commission.

“When I was trying to promote a young person for a position, [the university] had to trust me,” he says.

Kick-starting careersGraduate students at the beginning of their careers have expressed the most dissatisfaction with the alphabetical author list. But a survey on authorship at an experiment at the SLAC National Accelerator Laboratory proved that they’re not the only ones. Of 235 members of the BaBar collaboration who participated in the 2006 survey, 58 percent favored changing the alphabetical author list in some way. Of the 48 graduate students who replied to the survey, 73 percent were unhappy with the status quo.

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Honorable mention Standing out from the crowd can be difficult for researchers in large col-

laborations. The Commission on Particles and Fields of the International Union of Pure and Applied Physics has recommended seven ways to help highlight individual achievements.

Collaborations should:• writeclear,publiclyavailablerulesregardingwhoisaneligibleauthorfor

each publication.• releaseapublicWebpagewithsupportingnotesanddetailsaboutindividual

contributions for each publication.• publishscientificandtechnicalnoteswrittenbysmallgroupsofauthors.• keepapublicrecordofwaysmembershavecontributedbytaking

responsibilities such as writing refereed internal notes, speaking at con-ferences and holding leadership positions inside the collaboration.

• considerusingatwo-tieredauthorlisttoemphasizespecialcontributionsto publications without cutting out other contributors.

Collaboration members should:• includealistof“mostrelevantpublications”—thosetowhichtheymade

the largest contributions—on their curriculum vitae, rather than simply listing all publications on which they are named as authors.

Organizations and collaborations should:• awardmoreprizesforindividualachievementsinparticlephysics.

Photo: Reidar Hahn, Fermilab

A list of all the people who contribute to a modern par-ticle physics experiment from conception through design, construction, opera-tion and data analysis can be very, very long.

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Honorable mention Standing out from the crowd can be difficult for researchers in large col-

laborations. The Commission on Particles and Fields of the International Union of Pure and Applied Physics has recommended seven ways to help highlight individual achievements.

Collaborations should:• Writeclear,publiclyavailablerulesregardingwhoisaneligibleauthorfor

each publication.• ReleaseapublicWebpagewithsupportingnotesanddetailsaboutindividual

contributions for each publication.• Publishscientificandtechnicalnoteswrittenbysmallgroupsofauthors.• Keepapublicrecordofwaysmembershavecontributedbytaking

responsibilities such as writing refereed internal notes, speaking at con-ferences and holding leadership positions inside the collaboration.

• Considerusingatwo-tieredauthorlisttoemphasizespecialcontributionsto publications without cutting out other contributors.

Collaboration members should:• Includealistof“mostrelevantpublications”—thosetowhichtheymade

the largest contributions—on their curriculum vitae, rather than simply listing all publications on which they are named as authors.

Organizations and collaborations should:• Awardmoreprizesforindividualachievementsinparticlephysics.

Photo: Reidar Hahn, Fermilab

A list of all the people who contribute to a modern par-ticle physics experiment from conception through design, construction, opera-tion and data analysis can be very, very long.

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Some of the IUPAP commission’s suggestions for addressing this concern were uncontroversial. For example, it’s difficult to argue with the idea that collaborations should make authorship rules clear and public.

Many representatives of high-energy physics experiments who reviewed the report also liked the idea of keeping track of people who had held positions of authority inside the collaboration. The only problem is that no one can remember who did what over years or decades of research, says Dmitri Denisov, spokesman for Fermilab’s DZero experiment, which started in 1984.

“We were looking forward,” Denisov says. “We didn’t keep detailed track of the past.”

McBride says collaborations may be reluctant to take on additional record-keeping responsibili-ties in the future: “It’s work to set up and maintain records and make them public.”

Listing everyone in the collaboration as authors recognizes that without their help, there would be no experiment, says University of Cincinnati physics professor Kay Kinoshita, who works with the Belle collaboration, based in Japan. But small subgroups are usually responsible for writing the code, running the jobs, and making the plots necessary to produce papers.

“There’s usually one person writing,” Kinoshita says. “Like writing code, writing a cohesive piece of prose is very difficult to do with more than one person.”

The people doing that writing are more often than not graduate students and postdoctoral researchers, says Gabriele Simi, a postdoc at the University of Maryland who works with the BaBar collaboration.

“The higher-level professors do a lot of the thinking and reviewing and the very important task of managing and choosing the right people for the right job,” he says. “But in the end, they’re not

always the ones who do the analysis and the writing of the articles and the technical and ser-vice work.”

Alternatives to alphabeticalThe frustration of appearing as the 400th name on an alphabetic list after weeks or months of labor has fueled many a lunch-table vent-ing session.

As a partial solution, the Belle collaboration uses a unique system to slim its author lists. Rather than including everyone automatically, it requires each potential author to opt in.

“I think there was a consensus that the collab-oration members should at least be aware of papers,” Kinoshita says. “People should have at least have read a paper, understood the result, and made some decision on whether they agree.”

Kinoshita says she signs about two-thirds of the Belle papers, which come out at a rate of two or three per month. “If I have time to read a paper and think it’s pretty good, I’m happy to sign,” she says.

University of Warwick physicist Tim Gershon, who has also worked on Belle, says the rule changed attitudes toward publications. “I did find that it encouraged a very vibrant atmosphere within the collaboration in which the latest results were discussed,” he says.

The collaboration also highlights a paper’s main authors at the top of the list, as long as no one objects to the names proposed.

Lingering doubtIn the year before releasing its recommendations, the IUPAP commission’s working group sought feedback from major collaborations. But some concerns remain.

Rob Roser, spokesperson for the CDF collab-oration at Fermilab, says he worries that the

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process of singling out those who have made the most important contributions is too subjective.

“We all have our own definition of what an ideal physicist is,” Roser says. “I don’t see why a person who made this final plot is more important than the person who made the detector the whole analysis was predicated on.”

Researchers in the ATLAS collaboration at CERN’s Large Hadron Collider fear that using two-tiered author lists would recognize physi-cists who perform analysis at the expense of those who are hardware-oriented, says ATLAS Deputy Spokesperson Steinar Stapnes. Many physicists and engineers have put in a decade of work at the LHC.

“It would be incredibly unfair to put in the front the people who have done the final steps of the analysis,” Stapnes says. “They may not have even participated in the construction.”

Others also worry that honoring some people over others through awards or abridged author lists might cause unhealthy competition, ZEUS physicist Saxon says.

“There’s a danger of rivalry, people not sharing information,” he says. “It can be destructive of the collaboration. As collaborations have got larger, the need to work hard on cohesion has increased.”

Beyond the authors’ list As important as publications are, they are only one part of a physicist’s credentials.

Particle physicists applying for tenure at Duke University need to demonstrate their contribu-tions to publications during their time as faculty members, Gauthier says. But a typical particle physicist coming up for tenure might have 200 publications.

So Gauthier asks candidates to identify 10 pub-lications for which they have played a primary

role. According to the American Physical Society, a scientist must make several key contributions such as conceptualizing the project; collecting, analyzing, or interpreting the data; or writing the publication to be considered a primary author.

For his part, Aaltonen says he does not worry about author lists. “If I look for a job in physics,” he says, “people know the story of the author list. If I look for a job outside the science community, then people are probably more interested in my hands-on experiences than in papers.”

CDF’s Roser says that most of the time what really counts is how candidates present them-selves and what others say about them.

“Recommendations get you the interview. You get yourself the job,” he says. “In the end the cream does rise to the top. People know who they are, and they figure out a way to be successful.”

Even if they have to swim through an ocean of names to get there.

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gallery: sergio cittolin

Sergio Cittolin is first and foremost a physicist in search of answers to the mysteries of the universe. Yet he also has an artistic bent, and his talent for drawing has woven itself nicely into his 30 years of work at CERN. The result is a collection of Leonardo da Vinci-style illustrations that brighten CERN hallways, a book, and the covers of a number of technical documents.

Cittolin has been an incessant doodler since his early years in Vittorio Veneto, Italy. He has sketched his way through school lectures and professional meetings. Now in charge of trigger and data acquisition for the Compact Muon Solenoid experiment at the Large Hadron Collider, he tends to chair meetings rather than just attend them; “This has made it more difficult to find the time to sketch,” he admits.

Channeling da VinciA physicist sketches science in the style of an old master.

By Lisa McCarthy

Below: Particle events depicted as books. The few stacked neatly in piles are events selected by the CMS high-level trigger system for further study; more than 99 percent have been rejected and tossed in a pile. Facing page: Like a body on the anatomy table, the detector is dissected to extract information about particle events.

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9In 1992 the first of Cittolin’s da Vinci-style drawings appeared on the cover of a CMS experiment design report. With collider operations still years away and key technologies not yet invented, “I thought that the Leonardo style was suitable to give the feeling of anticipation of new ideas,” he says. “Da Vinci was the father of all engineers and described many of his inventions a long time before technology was ready to realize them.”

As a naturalist, da Vinci probed, prodded, and tested his way to a deeper understanding of how organisms work and why, often dissecting his object of study with this aim. “I thought, why not present the idea of data analysis to the world within the naturalist world of Leonardo?” Cittolin says. In the drawing below, the CMS detector is the organism to be opened; the parti-cles passing through it and the tracks they leave behind are organs exposed for further investigation.

Cittolin brings a sense of humor to his work. For example, after betting CMS colleague Ariella Cattai that he could produce a quality drawing for the cover of the CMS tracker technical proposal by a given deadline, he included in the drawing a secret message in mirror-image writing—which was also a favorite of da Vinci’s. The message jokingly demanded a particular reward for his hard work. The completed picture was delivered on time and within a few hours Cattai cleverly spotted and deciphered the

message. She promptly presented him with the requested bottle of wine.

Paris Sphicas, physics coordinator for the CMS experiment, says of Cittolin’s artwork, “The graphics are amazing in numerous ways. Foremost is the depiction of modern-day systems and actions in terms of medieval elements: the tons of data are drawn as piles of books; lasers become oil lamps; complicated systems, typically electronic, find mechanical analogs which are ingeniously conceived. Second, all these elements are combined in a way that the drawing gives, literally, a very short summary of what takes about 500 pages to describe. Third, it’s the art itself: it’s all drawn in the da Vinci style. From the text—which, of course, reads backwards and can only be deciphered in front of a mirror—to the line technique, the drawings look and feel like genuine works of Leonardo himself.”

Even with 10 technical manual covers to his credit, having his illustrations published in The Particle Odyssey by Oxford University Press, and seeing his artwork exhibited on the walls of CERN, Cittolin is all about the physics. “The big-gest pleasure is to complete what I’ve started and see it working at the LHC,” he says. “It is a real adventure to build something so unique and maybe fundamental.”

As for his drawings, Cittolin modestly insists that they are “just pictures,” adding, “Maybe I will find more time to draw in retirement.”

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Below: In the first stage of sifting particle events to find the most interesting ones, algorithms in a two-dimen-sional matrix are used to identify electrons, jets and muons. Right: One slice of the CMS detector is cut away to expose the magnet coil. Facing page: A drawing of the innermost part of the CMS detector, bristling with silicon tiles, took inspiration from the nine circles of hell in Dante Alighieri’s Divine Comedy. Below that, the CMS detector is lowered into the experimental hall.

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Below: In the first stage of sifting particle events to find the most interesting ones, algorithms in a 2D matrix are used to identify electrons, jets and muons. Right: One slice of the CMS detector is cut away to expose the magnet coil. Facing page: A drawing of the innermost part of the CMS detector, bristling with silicon tiles, took inspiration from the nine circles of hell in Dante Alighieri’s Divine Comedy. Below that, the CMS detector is lowered into the experimental hall.

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deconstruction: standard model discoveries

Sixteen elementary types of particles form the basis for the theoretical framework known as the Standard Model of fundamental particles and forces. J.J. Thomson discovered the electron in

1897, while scientists at Fermilab saw the first direct interaction of a tau neutrino with matter less than 10 years ago. This graphic names the 16 particle types and shows when and where they were discovered. These particles

also exist in the form of antimatter particles, with the same mass and the opposite electric charge. Together, they account for about 300 subatomic particles observed in experiments so far.

The Standard Model also predicts the Higgs boson, which still eludes experimental detection. Experiments at Fermilab and CERN could see the first signals for this particle in the next couple of years. Other funda-mental particles must exist, too. The Standard Model does not account for dark matter, which appears to make up 83 percent of all matter in the universe.

*Scientists suspected for several hundred years that light consists of particles. Many experiments and theoretical explana-tions have led to the discovery of the photon, which explains both wave and particle properties of light.

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1968: SLAC 1974: Brookhaven & SLAC

1968: SLAC

1956: Savannah River Plant

1897: Cavendish Laboratory 1937 : Caltech and Harvard 1976: SLAC 1983: CERN

1962: Brookhaven 2000: Fermilab 1983: CERN

1947: Manchester University 1977: Fermilab 1923: Washington University*

1995: Fermilab 1979: DESY

up quark charm quark

down quark

electron neutrino

electron muon tau Z boson

muon neutrino tau neutrino W boson

strange quark bottom quark

top quark gluon

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The 1950s saw a proliferation of particle discoveries, thanks to the advent of accelerator-based experiments. By 1960, more than 100 particles were known and physicists began to find patterns. Slowly the Standard Model emerged. It has brought order to the particle zoo and explains a steadily increasing number of subatomic phenomena.

Here is a brief summary of 15 Nobel Prize-winning discoveries closely connected to the development of the Standard Model, beginning with the “particle explosion” in the 1950s. For more information, visit nobelprize.org. Text: David Harris and Kurt Riesselmann

Nobel work: finding the first evidence that protons and neutrons are made of smaller building blocks: quarksLaureates: Jerome Friedman, Henry Kendall, and Richard TaylorDiscovery made: 1968Nobel awarded: 1990

Nobel work: discovering the tau lepton, the first observation of a parti-cle that belongs to the third generation of elementary particlesLaureate: Martin Perl (sharing the prize with Frederick Reines)Discovery made: 1976Nobel awarded: 1995

Nobel work: placing particle phys-ics theory on a firmer mathematical foundation, elucidating the quantum structure of the electroweak theoryLaureates: Gerardus ‘t Hooft and Martinus VeltmanDiscovery made: 1971Nobel awarded: 1999

Nobel work: making contributions to the project that led to the first direct observation of the W and Z bosonsLaureates: Carlo Rubbia and Simon van der MeerDiscovery made: 1983Nobel awarded: 1984

Nobel work: discovering that as two quarks move away from each other they remain tightly bound together due to the strong nuclear force, medi-ated by the exchange of gluons. Laureates: David Gross, David Politzer, and Frank WilczekDiscovery made: 1973 Nobel awarded: 2004

Nobel work: pioneering work in the discovery of the charm quark, the fourth quark observed in experimentsLaureates: Burton Richter and Samuel TingDiscovery made: 1974Nobel awarded: 1976

Nobel work: predicting that the weak nuclear force violates parity, or mirror symmetry, which leads to experimental signatures in beta decay as well as decay of strange particlesLaureates: Tsung-Dao Lee and Chen Ning YangDiscovery made: 1956Nobel awarded: 1957

Nobel work: discovering that neu-tral K mesons, which contain a strange quark, violate the fundamental matter-antimatter symmetry known as CPLaureates: James Cronin and Val FitchDiscovery made: 1964Nobel awarded: 1980

Nobel work: showing that there are at least two types of neutrinos, thereby discovering the muon neutrinoLaureates: Leon Lederman, Melvin Schwartz, and Jack SteinbergerDiscovery made: 1962Nobel awarded: 1988

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Nobel work: predicting the bottom and top quarks to explain the sym-metry-violating behavior of particles containing a strange quarkLaureates: Makoto Kobayashi and Toshihide Maskawa (sharing the prize with Yoichiro Nambu)Discovery made: 1973 Nobel awarded: 2008

Nobel work: detecting cosmic neutrinos, produced by the sun and by supernova explosions, thus start-ing the field of neutrino astronomyLaureates: Raymond Davis and Masatoshi Koshiba (sharing the prize with Riccardo Giacconi)Discovery made: 1980sNobel awarded: 2002

Nobel work: detecting the first neutrino Laureate: Frederick Reines (sharing the prize with Martin Perl)Discovery made: 1956Nobel awarded: 1995

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Nobel work: classifying the experimentally observed particle zoo by introducing the concepts of strangeness and quarksLaureate: Murray Gell-MannDiscovery made: 1953, 1961, 1964Nobel awarded: 1969

Nobel work: discovering a large number of particles, achieved through the development of new detection and analysis toolsLaureate: Luis AlvarezDiscovery made: 1959–1964Nobel awarded: 1968

Nobel for: developing a unified elec-troweak theory that explains both the electromagnetic force (transmitted by photons) and the weak force (trans-mitted by W and Z bosons)Laureates: Sheldon Lee Glashow, Abdus Salam, and Steven WeinbergDiscovery made: 1960s Nobel awarded: 1979

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essay: lynn hecht schafran

Vacationing at the LHCIn August 2008 I built my summer vacation around a trip to CERN, the European high-energy physics laboratory near Geneva. I am a women’s rights lawyer and a former art historian, and it might seem unusual that someone so totally out-side the field would consider that fun.

My CERN visit actually culminated a ten-year interest in the Superconducting Super Collider. In the late 1980s, my real estate-developer hus-band wanted to participate in the Super Collider project, then planned for Waxahachie, Texas. He bought land adjacent to the site, intending to build an industrial park that would service con-struction and maintenance of the collider. Obviously there was an economic interest at play, but what attracted him to this location, as opposed to others, was the thrilling scientific enterprise expected to take shape there.

Then we watched in disbelief as Congressional funding for the project floundered and finally died in 1993. To us the cancellation seemed so short-sighted. How could Congress cede America’s primacy in particle physics? How could it toss the chance to uncover wonders with a Super Collider vastly more powerful than what would be possible in Europe?

Over the next years we watched plans emerge for CERN’s Large Hadron Collider, a 17-mile ring beneath the Swiss-French border that will produce particle collisions seven times more energetic than ever before achieved. I began reading more and more about particle physics—

a definite departure from the days when I left the Bronx High School of Science at the start of my junior year for fear that having to take physics and chemistry simultaneously would destroy my grade-point average. Although I understood only a scintilla of what I read, I was fascinated.

As the LHC start date neared, I found myself clipping more and more articles about it and feeling personally dismayed by the delays. I knew I would be following the news from CERN closely and wanted a concrete sense of the place from which it was emerging; hence my summer vacation.

Our tour was far more than I anticipated in every way: more than three hours long, with three CERN physicists leading the way. I now understand why visitors must be limited to one tour a year.

Back home I look with awe at the photographs in my CERN 2008 calendar and listen to my “Particle Physics for Non-Physicists” DVD series in the hope of understanding a bit more of what is being investigated there. I am among the myriad fans saddened that the LHC will not be operational until later in 2009, but I am comforted by something I learned from the physicist who led our official tour group.

He explained that the amount of data the LHC will produce is so staggering that even on the eve of activation, CERN physicists were still trying to determine how to best decipher which data were old news that should be discarded and which showed something new. So, painful as the delay may be, it provides more time to meet this chal-lenge and perhaps, in the end, will prove a boon.

Congratulations to everyone involved in this extraordinary project. I cannot wait to see what you discover.

Lynn Hecht Schafran is senior vice president of Legal Momentum and director of the organization’s National Judicial Education Program to Promote Equality for Women and Men in the Courts. She and her husband, Larry, live in New York City.

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logbook: earth’s radiation belts

Earth

James Van Allen barely had time to savor the launch

of America’s first satellite, Explorer I, on Jan. 31, 1958, when scientists at the Jet Propulsion Laboratory told him the Geiger tube cosmic-ray detector his team had built wasn’t working. The instrument kept blanking out, leaving baffling gaps in the data transmitted to radio stations on Earth.

The University of Iowa astrophysicist set his sights on solving this mystery. His graduate student, George Ludwig, was already refining a smarter counter with a miniature tape recorder, and it launched aboard Explorer III on March 26, 1958.

Van Allen received the first data from Explorer III while in Washington, DC. He bought a ruler and paper and plotted graphs in his hotel room until 3 a.m. He found what he was looking for: the detector stuttered to a halt each time Explorer III’s irregular orbit ventured into an area more than 500 miles above ground. He and his colleagues now had proof for a high-radiation zone that had satu-rated and silenced the instruments. The first discovery of the space age, made just a few months after the Soviets launched Sputnik, had been hiding in the gaps.

The handwritten entry from Van Allen’s journal, made on Dec. 13, 1957, shows his schematic for the transmis-sion of data gathered by his cosmic-ray detectors as well as by temperature sensors and micrometeorite gauges designed by other labs for Explorer I and III.

Particle detectors on Pioneer spacecraft in 1958 and 1959 allowed Van Allen to map a cross section of two radiation zones that reached thousands of miles into space. Below is the drawing he made for one of his first science articles about them, indicating altitude in multiples of the Earth radius and showing the contours of the zones based on radiation levels. The line crossing through the zones shows the trajectory of Pioneer 4.

The radiation zones, which contain high-energy charged particles trapped by Earth’s magnetic field, became known as the Van Allen radiation belts. On May 4, 1959, Van Allen and his cosmic-ray detector made the cover of Time magazine.Abigail Foerstner, Northwestern University

Abigail Foerstner is the author of James Van Allen: The First Eight Billion Miles, published in 2007 (University of Iowa Press).

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logbook: earth’s radiation belts

Earth

James Van Allen barely had time to savor the launch

of America’s first satellite, Explorer I, on Jan. 31, 1958, when scientists at the Jet Propulsion Laboratory told him the Geiger tube cosmic-ray detector his team had built wasn’t working. The instrument kept blanking out, leaving baffling gaps in the data transmitted to radio stations on Earth.

The University of Iowa astrophysicist set his sights on solving this mystery. His graduate student, George Ludwig, was already refining a smarter counter with a miniature tape recorder, and it launched aboard Explorer III on March 26, 1958.

Van Allen received the first data from Explorer III while in Washington, DC. He bought a ruler and paper and plotted graphs in his hotel room until 3 a.m. He found what he was looking for: the detector stuttered to a halt each time Explorer III’s irregular orbit ventured into an area more than 500 miles above ground. He and his colleagues now had proof for a high-radiation zone that had satu-rated and silenced the instruments. The first discovery of the space age, made just a few months after the Soviets launched Sputnik, had been hiding in the gaps.

The handwritten entry from Van Allen’s journal, made on Dec. 13, 1957, shows his schematic for the transmis-sion of data gathered by his cosmic-ray detectors as well as by temperature sensors and micrometeorite gauges designed by other labs for Explorer I and III.

Particle detectors on Pioneer spacecraft in 1958 and 1959 allowed Van Allen to map a cross section of two radiation zones that reached thousands of miles into space. Below is the drawing he made for one of his first science articles about them, indicating altitude in multiples of the Earth radius and showing the contours of the zones based on radiation levels. The line crossing through the zones shows the trajectory of Pioneer 4.

The radiation zones, which contain high-energy charged particles trapped by Earth’s magnetic field, became known as the Van Allen radiation belts. On May 4, 1959, Van Allen and his cosmic-ray detector made the cover of Time magazine.Abigail Foerstner, Northwestern University

Foerstner is the author of James Van Allen: The First Eight Billion Miles, published in 2007 (University of Iowa Press).

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SymmetryA joint Fermilab/SLAC publicationPO Box 500MS 206Batavia Illinois 60510USA

symmetry

The charm quark is one of six

quarks that, along with leptons, form the basic building blocks of ordinary matter. It is hundreds of times more massive than the up and down quarks that make up protons and neutrons.

Theorists had predicted the existence of the charm quark to explain the absence of an expected particle interaction. When the charm quark did turn up, it was as a constituent of the J/psi particle, whose discovery in 1974 finally con-vinced physicists that quarks were real.

Particles containing a charm quark are known as either “charmed particles” or “charmonia.” They have only a fleeting existence before decaying into more conventional particles. Many experiments have studied their properties. At facilities known as “charm factories,” large numbers of charm-containing particles can be produced with little contamination from other types of par-ticles. An electron-positron collider in Beijing, for example, is expected to ultimately produce 10 billion J/psi decays in one year’s running time. This level of production allows scientists to observe subatomic processes with great preci-sion, and may reveal subtle signs of new physics phenomena predicted by theorists.Frederick A. Harris, University of Hawaii

explain it in 60 seconds

dimensions volume 06 particle a joint fermilab/slac publication … · 2019-12-31 · rhianna...

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