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Phys. Rev. a (Rapid Comm.) 40, 481 (1989)

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Phys. Rev. a (Rapid Comm.) 40, 481 (1989) Gabrielse 2006 Setting a Trap for Antimatter Gerald Gabrielse, ATRAP Spokesperson (CERN) Leverett Professor of Physics, Harvard Science and science fiction Warning: This Talk is Not About Science Fiction. Gabrielse Setting a Trap for Antimatter Support from NSF, AFOSR Matter and Antimatter? Particle and Atoms of Matter and Antimatter Annihilation Challenges Traps: Containers Without Walls Making Antimatter Atoms? Why Should We Do This? Gabrielse Where Did You Learn About Antimatter? Dr. Spock “knew” Antimatter annihilation Æ powered Star Trek space ship “Enterprise” “going boldly where no one had gone before” Gabrielse Generations of Trekies hardware: android software: hologram We study antimatter. How close are we to the Star Trek imagination? Gabrielse The Science Reality Behind the Science Fiction Imagination What is Matter? What is Antimatter? Gabrielse We Are Made of Matter Gabrielse Particles of Matter and Antimatter: Opposite and Identical charge mass Only measurements tell how identical Gabrielse Matter and Antimatter Atoms uncharged uncharged atom anti-atom Particle and antiparticle charges are opposite Both atoms are uncharged Æ same charge Gabrielse Gabrielse According to Physics as We Understand It Æ Looks Like the Whole Universe Could Have Been Made of Antimatter How would an antimatter universe be different? Why is our universe made of matter rather than antimatter? Gabrielse What Would I Look Like If I Were Made of Antimatter? • protons Æ antiprotons • neutrons Æ antineutrons • electrons Æ anti-electrons (positrons) ? Less mass? Handsome? More intelligent? Gabrielse What Would I Look Like If I Were Made of Antimatter? • protons Æ antiprotons • neutron Æ antineutrons • electrons Æ anti-electrons (positrons) Antimatter Gabrielse Big disappointment: • Antimatter Gabrielse looks the same! • Antimatter Gabrielse has the same mass! • Antimatter Gabrielse has the same limited brain power! Gabrielse Universe Made of Antimatter • Essentially the same as a universe made of matter • We only know two ways for inhabitants to know whether they live in a universe made of matter or antimatter (Need a large accelerator complex and sophisticated techniques) Why is our universe made of matter? (seems like antimatter would work just as well) Gabrielse Gabrielse Why Are Science Fiction Writers so Fascinated? Antimatter and Matter Particles Gabrielse Annihilate Each Other Gabrielse What Happens When Antimatter and Matter Gabrielse Meet? Anti-Gabrielse Gabrielse About to shake hands Gabrielse Huge Energy Release! 100 kg 100 kg Anti-Gabrielse Gabrielse energy mass that 200 kg released disappears E = mc2 Einstein’s famous formula 5,000,000,000,000 kilowatt-hours Yearly output of 500 nuclear power plants Energy from 4200 Megatons of TNT Gabrielse Energy Released Efficiency = Mass of Fuel Used Annihilation 100 % Nuclear fission 0.1 % Nuclear fusion 0.1 % (or a bit higher) Chemical fuel 0.000 000 3 % Annihilation • 1000 times more bang for the gram compared to nuclear fuel Energy Source of the Future? No, certainly not Antimatter Weapons? No, certainly not Antimatter Rockets? Doubtful, … maybe in distant future Gabrielse Antiproton Trapping and Annihilation Makes its Way Into Popular Culture Star Trek – antimatter powers the space ship Enterprise Serious Play: Hapgood Fiction best seller Author: Tom Stoppard Gabrielse Should the Pope Have Worried? Missing detail: if all the antiprotons we have made in the history of the world were annihilated at the same time Æ Not enough energy to boil a pot of tea Clearly the pope should have studied more science Gabrielse Gabrielse Embarrassing, Unsolved Mystery: How did our Matter Universe Survive Cooling After the Big Bang? Big bang Æ equal amounts of matter and antimatter created during hot time As universe cools Æ antimatter and matter annihilate Big Questions: • How did any matter survive? • How is it that we exist? Our experiments are looking for evidence of any way that antiparticles and particles may differ Gabrielse Our “Explanations” are Not so Satisfactory (My opinion) Baryon-Antibaryon Asymmetry in Universe is Not Understood Standard Explanation Alternate • CP violation • CPT violation • Violation of baryon number • Violation of baryon number • Thermodynamic non-equilibrium • Thermo. equilib. Bertolami, Colladay, Kostelecky, Potting Phys. Lett. B 395, 178 (1997) Why did a universe made of matter survive the big bang? Makes sense look for answers to such fundamental questions in the few places that we can hope to do so very precisely. Bigger problem: don’t understand dark energy within 120 orders of magnitude Gabrielse Gabrielse Low Energy Studies of Antimatter CERN Laboratory (Geneva) makes it We slow it, catch it, cool it, study it Start Need a container without walls to avoid annihilation here trap Gabrielse Particle Trap – A “Container Without Walls” Need two truths to understand particle trap 1. Charged particles go in circles near a magnet 2. Same sign charges repel Horseshoe Magnet --- negative antiproton --- Gabrielse ATRAP – Trap and Detectors Small View fibers positron 77 K source positron traps 5.3 Tesla magnetic field rotating electrode antiprotons 4.2 K antiproton traps BGO Harvard: Trap, vacuum, rf electronics 77 K Juelich: Scintillation detectors Garching, York, Mainz: Lasers Gabrielse Penning Trap (Harvard) Rotating • 4 K, 6 Tesla • electrode • single crystal • field emission point 1 cm Approx. (Photo by P. Horowitz) 100 leads Gabrielse Gabrielse One Charged Particle in a Trap One electron Æ more than 10 months One antiproton Æ several months Can study the particle properties with extremely high precision Antiproton and proton have the same charge-to-mass ratio to better than 1 part in 1010 = 10000000000 Measure the electron magnetic moment to better than 1 part in 1012 = 1000000000000 Æ Gives a new value for the fine structure constant α that is much more accurate Gabrielse So far, the most stringent CPT test with baryons comes from One-Antiproton Radio Antenna FM Radio Tuning Speaker “volume” frequency tuning Gabrielse Special Relativity Is Crucial Å year of Einstein Plan: Compare cyclotron frequency for antiproton and proton Æ compares Q/M for antiproton and proton (if B stays same) Æ test of CPT invariance for baryon/antibaryon system Problem: Antiproton cyclotron frequency shifts in time Highly non-relativistic antiproton Q K ω = B γ =+1 2 c M Mc 1eV =+1 1GeV =1.000000001 Actually, highly “relativistic” at 1 eV Å due to high resolution Q ω = B c γ M Extrapolate Einstein away K Æ 0 eV Gabrielse Polarization Effect Discovered with Molecular Ions J.K. Thompson, S. Rainville and D.E. Pritchard, Nature Lett. 430, 58 (2004) Motional radial electric field: E = vB Æ polarizes the ion radially: d = αE= -αvB Ion experiences • magnetic force on its charge: -evB • additional force on it dipole moment: -dωΒ The additional polarization force could be expected to vanish as we take the vÆ0 limit in our experiment ∆ω α B2 But, it does not. Instead c =− =70 ppt ωc M not really statistically significant (an excuse to measure more accurately?) corrected TRAP Improved the Comparison of AntiprotonGabrielse 6 qm/ (antiproton) and Proton by ~10 =−0.99999999991(9) qm/ (proton) 910×=−11 90ppt best CPT test with baryons -1 10 Bevatron (p discovery) (a) (b) 10-2 10-3 CERN (exotic 2 10-4 BNL atoms) 10-5 Trap II -6 10 ppb 1 10-7 TRAP I 5 -8 610× fractional accuracy fractional 10 10-9 TRAP II TRAP III 10-10 TRAP III 0 1960 1970 1980 1990 2000 year 100 antiprotons and protons G. Gabrielse, A. Khabbaz, D.S. Hall, C. Heimann, H. Kalinowsky, W. Jhe; Phys. Rev. Lett. 82, 3198 (1999). Gabrielse Last TRAP Measurement of Antiproton Q/M improved Low Energy Antiproton Ring apparatus (LEAR) shut down and technique Could do significantly better! Q/M much more accurate than Q and M separately Gabrielse Given that q/m magnitudes are the same, could q and m change to keep q/m constant? TRAP: Directly compare q/m for antiproton and proton ASACUSA: Indirect measure of q2m for antiproton - antiprotonic He spectroscopy - and detailed structure calculations - measured Rydberg constant, etc. Comparisons of Antiproton and Proton TRAP: q/m same to fractional accuracy 0.000 000 000 09 ASACUSA: q2m same to fractional accuracy 0.000 000 06 Together: q and m same to fractional accuracy 0.000 000 06 q/m comparison is 700 times more accurate Gabrielse Gabrielse Digression: Quantum Limit of a Particle in a Trap ψ 2 One Electron Quantum Cyclotron 0.1 µm Student award symposium: Brian Odom, Thursday, 2 pm Gabrielse Quantum Cyclotron one electron Æ quantum average quantum number < 1, etc. Æ quantum υ c ≈ 150 GHz n = 4 n = 3 n = 2 n = 1 ωc = 7.2 kelvin B ≈ 6 Tesla n = 0 To realize a quantum cyclotron: • need cyclotron temperature << 7.2 kelvin • need sensitivity to detect a one quantum excitation Gabrielse Cylindrical Penning Trap Electrostatic quadrupole potential Æ good enough near trap center Gabrielse Quantum Jumps as a Function of Temperature • one electron • Fock states of a cyclotron oscillators • due to blackbody photons 0.23 0.11 0.03 9 x 10-39 average number On a short time scale of blackbody Æ in one Fock state or another photons in the Averaged over hours cavity Æ in a thermal state Gabrielse Quantum Jump Spectroscopy • lowest cyclotron and spin states • one electron in a Penning trap Gabrielse A New Measurement of the Electron Magnetic Moment magnetic S spin µµ= g moment B Bohr magneton e 2m g / 2= 1.001159 652 180 85 ±×0.000 000 000 000 76 7.6 10−13 • First improved measurement since 1987 • Nearly six times improved
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