big bang and microcosm: where did the antimatter go?horvath/talks/2014/antimatter_20141020.pdf ·...

Big Bang and Microcosm: WhereDid the Antimatter Go?

Dezso Horváth

horvath.dezso@wigner.mta.hu

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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