big bang and microcosm: where did the antimatter go?horvath/talks/2014/antimatter_20141020.pdf ·...
TRANSCRIPT
Big Bang and Microcosm: WhereDid the Antimatter Go?
Dezso Horváth
Wigner Research Centre for Physics,
Institute for Particle and Nuclear Physics, Budapest, Hungary
&
ATOMKI, Debrecen, Hungary
Dezso Horváth Antimatter 20 October 2014, New York, USA – p. 1/35
Outline
Antimatter and its lack in the Universe
CPT invariance: matter–antimatter
symmetry
The Antiproton Decelerator at CERN
Antimatter Spectroscopy
Outlook: ELENA
Use of Antimatter in Life
Dreams and Ridiculous Tales
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Foreword
Physics is an exact science (collection of formulae!)
It is based on precise mathematical formalism.
A theory is valid if concrete quantities can be calculated with it
and the results are confirmed by experiment.
The real physical terms are measurable quantities, words are
just words.
Behind the words there are
precise mathematics and experimental evidence
Physics is experimental science: without calculation and
experimental evidence a theory is considered to be
mere speculation.
What and how: Physics. Why: philosopy or theology.
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Birth of antimatter
Paul Dirac, 1928: Linear equation for the hydrogen atom.
Square root of a quadratic equation ⇒ two solutions for
electrons (x2 = 4 ⇒ x = ±2).
Two kinds of electrons:
+ mass and− charge (ordinary electron);
− mass and+ charge (anti-electron = positron).
Negative mass non-physical. Dirac thought particle holes.
Carl Anderson (1932): e+ in cosmic rays!
⇒ real, existing particle: positron.
Nobel prizes (in 4 years): Dirac: 1933; Anderson: 1936
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Antiparticles
Every matter particle has an antiparticle
Proton (hydrogen nucleus) ↔ antiproton.
Particles and antiparticles must have the same properties
apart from the signs of charges.
When particle meets its own antiparticle they annihilate to
photons or to lighter particles (energy conservation).
A slow positron in matter annihilates with an atomic electron by
emitting two gamma photons.
Converse reaction: radiation in the field of atomic nucleus can
produce particle + antiparticle pairs.
Low energy: e− + e+, higher energy (E > 2Mp): p + p.
e−
e+
γ
γ
γ
e−
e+
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Antimatter mysteries
Why there is practically no antimatter in our Universe?At the Big Bang particles and antiparticles should havebeen produced together. Where did antimatter go?
Could they be hiding in parts of the Universeinaccessible for us?
Could there be a tiny difference between particle andantiparticle to cause this asymmetry?
Are there particles which are their own antiparticles(Majorana particles)? Could the dark matter of theUniverse consist of such particles?
Can antimatter be used for something in everyday lifeor is it just an expensive curiousity?
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Matter–antimatter symmetry
This symmetry is called CPT invariance
Charge conjugation: C|p(r, t)> = |p(r, t)>
Space reflection: P |p(r, t)> = |p(−r, t)>
Time reversal: T |p(r, t)> = |p(r,−t)>
Basic assumption of field theory:
CPT |p(r, t)> = |p(−r,−t)> ∼ |p(r, t)>
meaning free antiparticle ∼ particlegoing backwards in space and time.
Giving up CPT one has to give up:
locality of interactions ⇒ causality, or
unitarity ⇒ conservation of matter,information, ... or
Lorentz invariance
e−
e+
γ
γ
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CPT -violating theories
Weak interaction violates P and CP symmetryTheoreticians in general: CPT cannot be violated
Standard Model valid up to Planck scale (∼ 1019 GeV).Above Planck scale new physics ⇒Lorentz violation possible
Quantum gravity: fluctuations ⇒ Lorentz violationloss of information in black holes ⇒ unitarity violation
Motivation for testing CPT at low energy
Quantitative expression of Lorentz and CPT invarianceneeds violating theory
low-energy tests can limit possible high energyviolation
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How to test CPT?
Particle = – antiparticle ?
[m(K0)−m(K0)]/m(average) < 10−18
proton ∼ antiproton? (compare m, q, ~µ)
hydrogen ∼ antihydrogen? (2S − 1S, HFS)
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CERN: 21 + 1 member states
Israel
2013
Romania
2015
Serbia, Cyprus, Ukrainia, Pakistan
member candidates
Brasil, Slovenia, Turkey
under discussion
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Researchers (users) of CERN
2800 employees + 10500 users + 440 students(Italian > German > American > Russian > French)
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Accelerators at CERN1989–2000 2009–2025??
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The Antiproton Decelerator at CERN
has been built to test CPT invariance
Three experiments test CPT:
ATRAP: q(p)/m(p) ↔ q(p)/m(p)
H(2S − 1S) ↔ H(2S − 1S)
ALPHA: H(2S − 1S) ↔ H(2S − 1S)
ASACUSA: q(p)2m(p) ↔ q(p)2m(p)
µℓ(p) ↔ µℓ(p)
H ↔ H HF structure
RED: done, GREEN: plannedc©Ryugo S. Hayano
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Mass and Charge of Antiproton
Proton’s well (?) known:m(p)/m(e) = 1836.15267245(75)
q(e) = 1.602176565(35)× 10−19 C
Precision: 4 · 10−10 and 2 · 10−8
Relative measurements: proton vs. antiprotonCyclotron frequency in trap → q/m
TRAP ⇒ ATRAP collaborationHarvard, Bonn, München, Seoul
p and H− together ⇒ 10−10 precision
Atomic transitions:En ≈ −mredc
2(Zα)2/(2n) → m · q2
PS-205 ⇒ ASACUSA collaborationTokyo, Brescia, Budapest, Debrecen, Munich, Vienna
Atomic
Spectroscopy
And
Collisions
Using
Slow
Antiprotons
Asakusa, Tokyo
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Antihydrogen: e+–p atom
2S − 1S transition with 2-photons
Long lifetime, narrow transition, Doppler-free spectroscopy
M. Charlton, J. Eades, D. Horváth, R. J. Hughes, C. Zimmermann:
Antihydrogen physics, Physics Reports 241 (1994) 65.
M.H. Holzscheiter, M. Charlton, M.M. Nieto:
The route to ultra-low energy antihydrogen, Physics Reports 402 (2004) 1.
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Steps toward antihydrogen spectroscopy
Putting antiprotons (p) in electromagnetictrap
Trapping and cooling antiprotons
Cooling slow positrons (e+ from 22Na) intrap
Mixing pand e+ → recombination
Trapping antihydrogen, waiting fordeexcitation
2014
Cooling antihydrogen
Laser spectroscopy on antihydrogenFuture
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Antihydrogen beam
ASACUSA: MUSASHI
Monoenergetic
Ultra
Slow
Antiproton
Source for
High–precision
InvestigationsMusashi Miyamoto self-portrait ∼ 1640
5.8 MeV p injected into RFQ
100 keV p injected into trap
106 p trapped and cooled (2002)
∼ 350000 slow p extracted (2004)
Cold p compressed in trap (2008)
(5× 105 p, E = 0.3 eV, R = 0.25 mm)
H-beam formed: ASACUSA, 2010–2012
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Spectroscopy with H-beam
p e
antiproton and positronTrap / R ecombination
S extupole I
MicrowaveC avity
S extupole II
AntihydrogenDetector
+
H-beam path: polariser, resonator, analyserAnalogy to polarised light
R.S. Hayano, M. Hori, D. Horváth, E. Widmann, Rep. Progr. Phys. 70 (2007) 1995.
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Extra Low ENergy Antiprotons (ELENA)
Physics Motivation
Test the Standard Model and General Relativity forantimatter
Test SM extensions for antimatter (Lorentz-violation,black holes, new interactions, ...)
Stringent CPT tests with antihydrogen
Antimatter gravity measurement (weak equivalence)
Added precision for physical constants (CODATA) as-suming CPT invariance
All existing AD experiments profit, new ones made possible(gravity, X-rays, nuclear studies)
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ELENA at the AD: plan
M.-E.Angoletta et al: ELENA: A Preliminary Cost And Feasibility Study,
CERN-AB-2007-079.
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Antimatter in Space
AMS-2: Alpha Magnetic Spectrometer
to discover antimatter (anti-helium!) and
dark matter
Mass: 8500 kg,
1200 kg perm. magnet
Father: Sam Ting, cost: 2 G$
Construction: CERN
Launch: May 2011, USA
Control room: CERN
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AMS-2: Alpha Magnetic Spectrometer
First results (2013-14):
No antihelium observed.
High energy positrons everywhere.
Could come from dark matter or pulsars.
AMS2 will collect data for 10–15 years.Dezso Horváth Antimatter 20 October 2014, New York, USA – p. 22/35
Conclusion (science-wise)
ASACUSA at AD
Two-photon spectroscopy of antiprotonic helium: results agree with 3-body
calculations.
Determined Mp/me ratio to 1.3 ppb. Result agrees with CODATA proton
value (0.4 ppb).
Further improvement partially hindered by theoretical uncertainty.
Future prospects
Colder atoms, better lasers, better detectors.
ELENA (colder antiproton beams at 100 keV of higher luminosity).
Spectroscopy with trapped antihydrogen and with antihydrogen beam.
AMS2 delivers more and more data on antimatter in space.
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Practical applications
Nice (and expensive) physics, can it be used?
Positron Emission Tomography (PET): yes!
AD: Antiproton Cell Experiment (ACE):cancer therapy with p?
Rocket fuel???
Antimatter bomb ...
Reality — dream — phantasy — stupidity
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Positron Emission Tomography (PET)
Diagnostics: metabolismIn Hungary pioneer: Debrecen
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Antiproton Cell Experiment (ACE)
Cancer therapy research (USA) at AD of CERN
Advantage: Antiprotons lose energy in very small volume,choosing the right energy concentrates damage in tumor.
Disadvantage: Antiprotons are very expensive andannihilation radiation damages as well.
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Rocket Fuel???Star Trek ⇒ Positronics Research LLC (NASA!)
Antimatter storage: solved (??)
2001: Mars rocket with antiprotons (??)
2009: Mars rocket with positron reactor (??)(less radiation dose for astronauts)
http://www.nasa.gov/exploration/home/antimatter_spaceship.html
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Dan Brown: Angels and Demons (2000)Story: A terrorist steals a bottle of antimatter from a secret
laboratory of CERN to destroy Vatican with it. The hero stops it just
in time.
CERN created a web page for the book:
CERN indeed exists, it has the largest particle
accelerator, the Large Hadron Collider, a 27 km
ring 100 m underground.
It is an open facility, has neither secret
laboratories, nor any problem with Vatican.
CERN produces antihydrogen atoms (cannot
make anything heavier) at the Antiproton Dece-
lerator (not at LHC) in microscopic quantities, for
pure scientific aims: it cannot be transported and
cannot make bombs.
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Angels and Demons: the film, 2009
CERN invited the fim makers and offered CERN forshooting the beginning. They made photos and
reconstructed LHC for the film (quite well). We joked thatthey may find the Higgs boson before us.
Tom Hanks at the ATLAS detectorDezso Horváth Antimatter 20 October 2014, New York, USA – p. 29/35
Angyalok és démonok a CERN-ben
CERN: home page andexhibition for the film:
2009
Sony Pictures agreed,but asked us not to
emphasize howridiculous it isscientifically.
USA: lectures in theopening night of the
film.
Europe did not do it...
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Angels and Demons: exhibition
Tom Hanks, Ayelet Zurer and Ron Howard before the exhibition center of
CERN, when the Angels & Demons exhibition was opened
CERN: The Globe of Science and Innovation
EXPO 2002: Swiss wood construction, donated to CERN
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Angels and Demons: exhibition in Globe
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Making antimatter atoms at AD
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Antimatter storage in the film
3-ton antiproton trap at AD
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Thanks for your attention
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