Professor Peter I. P. Kalmus Queen Mary, University of London

1. ANTIMATTER RETTAMITNA Professor Peter I. P. Kalmus Queen Mary, University of London

2. Study of the ultimate constituents of matter Nature of the interactions between them Objectives of Particle Physics atom electron nucleus proton neutron quarks

3. Structure of the Atom Proton + Neutron strong force Early 20th Century electron, nucleus 1930s electric force electromagnetism Nucleus Atom bunch of grapes ~ 10-10m ~ 10-15m town

4. g + N e- + e+ + N e- + e+g + g Antiparticles equal and opposite properties “predicted”, later discovered Creation Einstein E = mc2 > 1 MeV Annihilation now used in positron emission tomography 1950s Antiproton, antineutron Nobel prizes Dirac, Anderson, Blackett, Segre, Chamberlain > 200 new “elementary” (?) particles E = mc2

5. Leptons (do not feel strong force) electron e- -1 e-neutrino ne 0 Quarks (feel strong force) up u +2/3 down d -1/3 Today’s building blocks 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

6. Leptons (do not feel strong force) electron e- -1 e-neutrino ne 0 Quarks (feel strong force) up u +2/3 down d -1/3 Today’s building blocks muon m- -1 m-neutrino nm 0 charm c +2/3 strange s -1/3 tau t- -1 t-neutrino nt 0 top t +2/3 bottom b -1/3

7. Leptons (do not feel strong force) electron e- -1 e-neutrino ne 0 Quarks (feel strong force) up u +2/3 down d -1/3 baryons q q q antibary. q q q mesons qq Today’s building blocks Also antileptons antiquarks 6 leptons 6 antileptons 6 quarks 6 antiquarks muon m- -1 m-neutrino nm 0 charm c +2/3 strange s -1/3 tau t- -1 t-neutrino nt 0 top t +2/3 bottom b -1/3

8. Forces Electro- magnetic atoms molecules optics electronics telecom. Weak beta decay solar fusion Strong nuclei particles Gravity falling objects planet orbits stars galaxies short range gluon inverse square law photon short range W±, Z0 inverse square law graviton

9. Ultra-high energy collision A B Equal nos. particles & antiparticles

10. History of the Universe LHC

11. Antimatter Annihilation of Antigalaxy ? Telescopes X Cosmic rays ? AMS (Space station) Alfven hypothesis Anti-hydrogen : made in lab Bulk antimatter ? Where ? Difficult to detect Earth, Moon, X Solar system X Antistars in our Galaxy ? Other (anti-) galaxies ? Signal ? e+ + e - g + g 0.511 MeV g-ray “line” g g g Radiation pressure

12. Symmetries Particleantiparticle Do(1232) p + p- Do(1232) p + p+ Many in physics Powerful tools. We consider 2 1 C charge conjugation should occur at exactly same rate

13. Symmetries Mirror reflection Mirror symmetry A and B equally probable (parity conservation) Before 1957 believed valid for all processes P parity 2 A B

14. Communication with an Alien If parity conserved cannot tell which is his right hand radio signals

15. Parity violation Parity violated in weak interactions ! L R electrons only in this direction 60 Co 60 Ni + e- + n radioactive cobalt source direction of electrons in coil If parity conserved expect equal probabilities L and R superimpose object and mirror image Parity conserved in all strong and e-m interactions

16. Alien This one Can now ask alien to set up a parity violation experiment and hence deduce right hand

17. C violation P e- Also shown by same expts. e- e- Current reversed in antiwire wire C C P e+ e+ diagram looks same as original red Antiblue e+ emitted positrons go opposite way positrons in antiwire CP appears conserved

18. C violation P Experiments have been done with spinning muons m- m- e- e- C C P e+ diagram looks same as original red Antiblue m+ CP appears conserved emitted positrons go opposite way

19. Problem ? R L Right-handed green man Left-handed anti green man

20. Meet in space Teach him about our customs If he holds out his left hand

21. Annihilation

22. K0( d s ) ; K0( d s ) p+ + e- + n CP violation Discovered in decays of neutral kaons p- + e+ + n slightly more probable (0.6 %) KL Now can unambiguously define antimatter If the less abundant lepton in KL decay has the same sign as the local atomic nuclei, we have antimatter

23. Up till year 2000 only seen in neutral K decays CP Violation Believed to be responsible for domination of matter Reason for CP violation not yet understood Where else might we see CP violation ? Neutral B meson system 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.

24. Symmetric: no good Asymmetric : successful e+ e- e- e+ Bo Bo after collision after collision Bo Bo CP violation in B system Measured recently includes QMUL physicists and graduate students BaBar (SLAC, USA) Belle (KEK, Japan) e+ e-(4S) Bo Bo upsilon

25. Large CP violation observed At BaBar and Belle QMUL physicist

26. of the fundamental forces of nature Unification Faraday, Maxwell Newton Electricity Magnetism Apples Planets Electro- magnetic Gravity

27. Faraday, Maxwell Newton Electricity Magnetism Apples Planets Electro- magnetic Gravity Weak Strong Salam, Weinberg, Glashow Electroweak unified force g, W +, W -, Z o 0 80 80 90 GeV of the fundamental forces of nature Unification Do the W and Z particles really exist ?

30. Collider ~ Inject anti- protons RF cavities electric kick Bending electro- magnet Carlo Rubbia Antiprotons Collide 2 beams Inside vacuum Focusing electro- magnet Simon van der Meer Stochastic cooling Inject protons

31. CERN 71-25 Laboratory I Nuclear Physics Division 26 November 1971 CERN 71-25 ORGANISATION EUROPÉENNE POUR LA RECHERCHE NUCLÉAIRECERNEUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH 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

32. electron W p + p W + X neutrino What should we look for ? W around 1 in 108 collisions Needle in a haystack ! e + n lots of particles

34. Finding the W p p collisions 109 Angles match 167 Record on tape 975,000 No hadronic energy 72 Electron trigger 140,000 Energy matches mom. 39 High ET 28,000 Visual inspection Hi. mom track 2,125 2 jet 23 electron + jet 11 electron no jet 5 Points to calorim. 1,104 No other calorim. tracks 276

35. E parallel to electron n Missing energy flow GeV electron direction 40 Events 20 with jets – 40 – 20 20 40 E normal n For each event, plot how much energy is missing, and the direction relative to the electron in which this flows to electron – 20 – 40

36. E parallel to electron n Missing energy flow GeV electron direction 40 Events 20 with jets – 40 – 20 20 40 E normal n For each event, plot how much energy is missing, and the direction relative to the electron in which this flows to electron – 20 – 40

37. Peter Kalmus Alan Honma Eric Eisenhandler Richard Keeler Reg Gibson Giordi Salvi Graham Thompson Themis Bowcock W and Z particles discovered UA1 Collaboration at CERN Included following members of Queen Mary 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

38. p.i.p.kalmus@qmul.ac.uk http://www.ph.qmul.ac.uk