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Antimatter Charters School Peter Kalmus March 2005 Professor Peter I. P. Kalmus Queen Mary, University of London RETTAMITNA ANTIMATTER
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Antimatter Charters School Peter Kalmus March 2005 Objectives of Particle Physics atom electron nucleus proton neutron quarks Study of the ultimate constituents of matter Nature of the interactions between them
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Antimatter Charters School Peter Kalmus March 2005 Structure of the Atom Atom ~ 10 - 10 m Nucleus Early 20 th Century electron, nucleus electric force electromagnetism 1930s bunch of grapes Proton + Neutron strong force town ~ 10 - 15 m
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Antimatter Charters School Peter Kalmus March 2005 Antiparticles equal and opposite properties “predicted”, later discovered > 200 new “elementary” (?) particles Creation Annihilation + N e - + e + + N e - + e + + 1950sAntiproton, antineutron Nobel prizes Dirac, Anderson, Blackett, Segre, Chamberlain Einstein E = mc 2 now used in positron emission tomography E = mc 2 > 1 MeV
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Antimatter Charters School Peter Kalmus March 2005 Today’s building blocks Leptons (do not feel strong force) electron e - -1 e-neutrino e 0 Quarks (feel strong force) up u +2/3 down d -1/3 proton = u u d +2/3 +2/3 -1/3 = +1 neutron = u d d +2/3 -1/3 -1/3 = 0 4 particles very simple multiply by 3 (generations) multiply by 2 (antiparticles) First generation
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Antimatter Charters School Peter Kalmus March 2005 Today’s building blocks Leptons (do not feel strong force) electron e - -1 e-neutrino e 0 Quarks (feel strong force) up u +2/3 down d -1/3 muon -1 -neutrino 0 tau -1 -neutrino 0 charm c +2/3 strange s -1/3 top t +2/3 bottom b -1/3
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Antimatter Charters School Peter Kalmus March 2005 Today’s building blocks Leptons (do not feel strong force) electron e - -1 e-neutrino e 0 Quarks (feel strong force) up u +2/3 down d -1/3 muon -1 -neutrino 0 tau -1 -neutrino 0 charm c +2/3 strange s -1/3 top t +2/3 bottom b -1/3 Also antileptons antiquarks 6 leptons 6 antileptons 6 quarks 6 antiquarks baryons q q q antibary. q q q mesons q q
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Antimatter Charters School Peter Kalmus March 2005 Forces Gravity falling objects planet orbits stars galaxies inverse square law graviton inverse square law photon short range W ±, Z 0 Electro- magnetic atoms molecules optics electronics telecom. Weak beta decay solar fusion Strong nuclei particles short range gluon
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Antimatter Charters School Peter Kalmus March 2005 Ultra-high energy collision AB Equal nos. particles & antiparticles
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History of the Universe LHC
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Antimatter Charters School Peter Kalmus March 2005 Earth, Moon, X Solar system X Antistars in our Galaxy ? Other (anti-) galaxies ? Telescopes X Cosmic rays ? AMS (Space station) Antimatter Anti-hydrogen : made in lab Bulk antimatter ? Where ? Difficult to detect Annihilation of Antigalaxy ? Signal ? e + + e - + 0.511 MeV -ray “line” Alfven hypothesis Radiation pressure
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Antimatter Charters School Peter Kalmus March 2005 Symmetries Many in physics Powerful tools. We consider 2 Particle antiparticle o (1232) p + + o (1232) p + - should occur at exactly same rate C charge conjugation 1
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Antimatter Charters School Peter Kalmus March 2005 AB P parity Mirror symmetry A and B equally probable (parity conservation) Before 1957 believed valid for all processes Symmetries 2 Mirror reflection
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Antimatter Charters School Peter Kalmus March 2005 Communication with an Alien radio signals If parity conserved cannot tell which is his right hand
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Antimatter Charters School Peter Kalmus March 2005 superimpose object and mirror image If parity conserved expect equal probabilities L and R Parity violated in weak interactions ! L R 60 Co 60 Ni + e - + Parity violation Parity conserved in all strong and e-m interactions electrons only in this direction direction of electrons in coil radioactive cobalt source
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Antimatter Charters School Peter Kalmus March 2005 Alien Can now ask alien to set up a parity violation experiment and hence deduce right hand This one
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C violation Also shown by same expts. P C C P e-e- e-e- positrons in antiwire Current reversed in antiwire diagram looks same as original red e+e+ wire CP appears conserved emitted positrons go opposite way e+e+ e+e+ e-e- Antiblue
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Antimatter Charters School Peter Kalmus March 2005 C violation P C C P e-e- diagram looks same as original red e+e+ CP appears conserved emitted positrons go opposite way e-e- Antiblue Experiments have been done with spinning muons
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Antimatter Charters School Peter Kalmus March 2005 Problem Right-handed green man Left-handed anti green man RL ?
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Antimatter Charters School Peter Kalmus March 2005 Meet in space If he holds out his left hand Teach him about our customs
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Antimatter Charters School Peter Kalmus March 2005 Annihilation
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Antimatter Charters School Peter Kalmus March 2005 CP violation Discovered in decays of neutral kaons - + e + + + + e - + slightly more probable (0.6 %) K 0 ( d s ) ; K 0 ( d s ) KLKL Now can unambiguously define antimatter If the less abundant lepton in K L decay has the same sign as the local atomic nuclei, we have antimatter
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Antimatter Charters School Peter Kalmus March 2005 CP Violation Believed to be responsible for domination of matter Reason for CP violation not yet understood Up till year 2000 only seen in neutral K decays Where else might we see CP violation ? Problem : B mesons have only very short lifetime ~ 10 -12 s Travel only fraction of millimetre at low energies Solution : Produce in asymmetric e + e - collider, and use relativistic boost to increase lifetime. Neutral B meson system
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Antimatter Charters School Peter Kalmus March 2005 e+e+ e-e- BoBo BoBo Asymmetric : successful after collision CP violation in B system BaBar (SLAC, USA) Belle (KEK, Japan) includes QMUL physicists and graduate students e + e - (4S) B o B o upsilon e+e+ e-e- BoBo BoBo Symmetric: no good after collision Measured recently
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Antimatter Charters School Peter Kalmus March 2005 QMUL physicist Large CP violation observed At BaBar and Belle
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Antimatter Charters School Peter Kalmus March 2005 Unification of the fundamental forces of nature ElectricityMagnetismApplesPlanets Electro- magnetic Gravity Faraday, MaxwellNewton
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Antimatter Charters School Peter Kalmus March 2005 Unification of the fundamental forces of nature Do the W and Z particles really exist ? ElectricityMagnetismApplesPlanets Electro- magnetic WeakStrong Gravity Faraday, MaxwellNewton Electroweak unified force Salam, Weinberg, Glashow , W +, W -, Z o 0 80 80 90 GeV
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Antimatter Charters School Peter Kalmus March 2005
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Collider Inject anti- protons Inject protons Collide 2 beams Inside vacuum RF cavities electric kick ~ Bending electro- magnet Focusing electro- magnet Carlo Rubbia Antiprotons Simon van der Meer Stochastic cooling
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ORGANISATION EUROPÉENNE POUR LA RECHERCHE NUCLÉAIRE CERN EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH CERN 71-25 Laboratory I Nuclear Physics Division 26 November 1971 CERN 71-25 LOW–MOMENTUM ANTIPROTON PRODUCTION AT THE CERN PROTON SYNCHROTRON P. I. P. Kalmus, E. Eisenhandler, W. R. Gibson, C. Hojvat L.C.Y. Lee Chi Kwong, T.W. Pritchard, E.C. Usher and D.T. Williams Queen Mary College, London M. Harrison and W. R. Range University of Liverpool M. A. R. Kemp, A. D. Rush and J. N. Woulds Daresbury Nuclear Physics Laboratory G. T. J. Arnison, A. Astbury, D.P. Jones and A.S.L.Parsons Rutherford High Energy Laboratory
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Antimatter Charters School Peter Kalmus March 2005 What should we look for ? W around 1 in 10 8 collisions Needle in a haystack ! p + p W + X e + lots of particles electron W neutrino
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Antimatter Charters School Peter Kalmus March 2005
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Finding the W p p collisions 10 9 Record on tape 975,000 Electron trigger 140,000 High E T 28,000 Hi. mom track 2,125 Points to calorim. 1,104 No other calorim. tracks 276 Angles match 167 No hadronic energy 72 Energy matches mom. 39 2 jet 23 electron + jet 11 electron no jet 5 Visual inspection
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Antimatter Charters School Peter Kalmus March 2005 GeV 40 20 – 40– 2020 40 – 20 – 40 electron direction E parallel to electron Events with jets E normal to electron Missing energy flow For each event, plot how much energy is missing, and the direction relative to the electron in which this flows
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Antimatter Charters School Peter Kalmus March 2005 GeV 40 20 – 40– 2020 40 – 20 – 40 electron direction E parallel to electron Events with jets E normal to electron Missing energy flow For each event, plot how much energy is missing, and the direction relative to the electron in which this flows
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Antimatter Charters School Peter Kalmus March 2005 W and Z particles discovered UA1 Collaboration at CERN Included following members of Queen Mary Peter Kalmus Alan Honma Eric Eisenhandler Richard Keeler Reg Gibson Giordi Salvi Graham Thompson Themis Bowcock Results confirmed by another CERN collaboration, and few years later at Fermilab USA Electroweak unification confirmed Nature’s fundamental forces reduced from 4 to 3 Nobel Prizes
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Antimatter Charters School Peter Kalmus March 2005 p.i.p.kalmus@qmul.ac.uk http://www.ph.qmul.ac.uk
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