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PANDA: An Experiment To Investigate Hadron Structure Using Antiproton Beams

PANDA: An Experiment To Investigate Hadron Structure Using Antiproton Beams

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PANDA: An Experiment To Investigate Hadron Structure Using Antiproton Beams

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  1. PANDA: An Experiment To Investigate Hadron Structure Using Antiproton Beams • Overview of the GSI Upgrade • Overview of the PANDA Physics Program • Exotic Hadrons in the Charm Mass Region • HESR: High Energy Storage Ring • The PANDA Detector James Ritman Univ. Giessen

  2. The GSI Future Project • Nuclear Structure: • paths of nucleo-synthesis • Heavy Ion Physics: • hot and dense nuclear matter • Ion and laser induced Plasma: • very high energy densities • Atomic physics: • QED, strong EM fields, Ion-Matter interactions • Physics with Antiprotons • properties of the strong force Project approved Feb 2003 James Ritman Univ. Giessen

  3. Why are hadrons so much heavier than their constituents? • p-A interactions • Are there other forms of hadrons? e.g. Hybrids qqg or Glueballs gg What Do We Want To Know? • Why don‘t we observe isolated quarks? • Q-Q potential in the charmonioum system James Ritman Univ. Giessen

  4. Why Don’t We See Isolated Quarks? James Ritman Univ. Giessen

  5. Charmonium – the Positronium of QCD • Charmonium • Positronium Mass [MeV] Binding energy [meV] 4100 y ¢¢¢ (4040) Ionisationsenergie P (~ 3940) 3 2 0 3900 D 3 (~ 3800) P (~ 3880) 3 3 D 3 S 3 S 3 1 3 3 3 D 1 2 1 0 1 2 3 D P (~ 3800) D 3 -1000 3 1 1 y ¢¢ (3770) 0 2 D 2 P 3 3 D 2 P 3 D 3 3 2 1 2 2 S 3 2 2 S 1 1 1 2 P 1 3 Threshold ¢ ~ 600 meV 0 y (3686) 3700 1 2 P 3 0 10-4 eV h ¢ (3590) -3000 c c (3556) 2 h (3525) c c (3510) 1 3500 c (3415) 0 -5000 3300 1 S 3 8·10-4 eV 1 S 1 1 0 -7000 y (3097) 3100 0.1 nm + - e e C 1 fm h (2980) C c 2900 James Ritman Univ. Giessen

  6. _ Probe large separations with highly excited qq states Charmonium Spectroscopy James Ritman Univ. Giessen

  7. Little is known about states above DD Open Questions • `c(3590) • confirm hc • Partial width mostly unknown • Precision spectroscopy James Ritman Univ. Giessen

  8. In pp annihilation all mesons can be formed Resonance cross section Measured rate Beam CM Energy Why Antiprotons? • e+e- annihilation via virtual photon: only states with Jpc = 1-- • Resolution of the mass and width is only limited by the beam momentum resolution James Ritman Univ. Giessen

  9. High Resolution • Crystal Ball: typical resolution ~ 10 MeV • Fermilab: 240 keV  p/p < 10-4 needed James Ritman Univ. Giessen

  10. Why Are Hadrons So Heavy? James Ritman Univ. Giessen

  11. Hadron Masses 2Mu + Md ~ 15 MeV/c2 Mp = 938 MeV/c2 Protons = (uud) ? no low mass hadrons (except p, K, h) spontaneously broken chiral symmetry (P.Kienle)

  12. Spontaneous Breaking of Chiral Symmetry Although the QCD Lagrangian is symmetric, the ground state need not be. (e.g. Fe below TCurie ) Example:

  13. The QCD vacuum is not empty Hadron masses are generated by the strong interaction with <qq> (also with gluon condensate) Quark Condensate The density of the quark condensate will change as a function of temperature and density in nuclei. This should lead to modifications of the hadron’s spectral properties. James Ritman Univ. Giessen

  14. Hadrons in the Nuclear Medium Reduction of <qq> Spectral functions <qq> S.Klimt et al., Nucl. Phys. A515, 429 (1990). W.Peters et al., Nucl. Phys. A632, 109 (1998).

  15. u u u u u u d d d d d d d d d d d d Hadron Production in the Nuclear Medium Mass of particles may change in dense matter Quark atom _ D+ d c attractive _ d c D- repulsive

  16. Advantages of p-A Reactions Compared to A-A Much lower momentum for heavy producedparticles (2 GeV for “free”)(Effects are smaller at high momentum) Open charm mass region (H atom of QCD) @HESR (single light quark) Well defined nuclear environment (T and r) James Ritman Univ. Giessen

  17. p _ X 3GeV/c X- Strange Baryons in Nuclear Fields Hypernuclei open a 3rd dimension (strangeness) in the nuclear chart • Double-hypernuclei:very little data • Baryon-baryon interactions:L-N only short ranged (no 1p exchange due to isospin) L-L impossible in scattering reactions K+K Trigger secondary target • X-(dss)p(uud)L(uds)L(uds)

  18. Exotic Hadrons James Ritman Univ. Giessen

  19. g g g Glueballs C. Morningstar PRD60, 034509 (1999) Self interaction between gluons  Construction of color-neutral hadrons with gluons possible exotic glueballs don‘t mix with mesons (qq) 0--, 0+-, 1-+, 2+-, 3-+,... James Ritman Univ. Giessen

  20. Charm Hybrids ccg Prediction in QCD: Collective gluon excitation (Gluons contribute to quantum numbers) Ground state: JPC = 1-+ (spin exotic) distance between quarks James Ritman Univ. Giessen

  21. Mixing With Mesonic States Width: could be narrow (5-50 MeV) since DD suppressed for some states O+- DD,D*D*,DsDs (CP-Inv.) (QQg)  (Qq)L=0+(Qq)L=0 (Dynamic Selection Rule) If DD forbidden, then the preferred decay is (ccg)  (cc) + X , e.g. 1-+  J/Y+w,f,g James Ritman Univ. Giessen

  22. Partial Wave Analysis Partial wave analysis as important tool Example of 1-+(CB@LEAR) pd  X(1-+)+p+p, X  h p Strength ~ qq States ! Signal in production but not in formation is interesting ! James Ritman Univ. Giessen

  23. The Experimental Facility James Ritman Univ. Giessen

  24. HESR

  25. HESR: High Energy Storage Ring Beam Momentum 1.5 - 15 GeV/c High Intensity Mode: Luminosity 2x1032 cm-2s-1 (2x107Hz) dp/p (st. cooling) ~10-4 High Resolution Mode: Luminosity 2x1031 cm-2s-1 dp/p (e- cooling) ~10-5 James Ritman Univ. Giessen

  26. James Ritman Univ. Giessen

  27. Target • A fiber/wire target will be needed for D physics, • A pellet target is conceived: • 1016 atoms/cm2 for D=20-40mm 1 mm James Ritman Univ. Giessen

  28. Micro Vertexing 7.2 mio. barrel pixels 50 x 300 μm 2 mio. forward pixels 100 x 150 μm James Ritman Univ. Giessen

  29. example event: pp f f  4K Central Tracking Detectors • MVD: (Si) 5 layers • Straw-Tubes: 15 skewed double-layers • Mini-Drift-Chambers

  30. Example reaction: pp  J/y + F (s = 4.4 GeV/c2) Tracking Resolution Single track resolution Invariant mass resolution J/y  m+m- F K+K- s(J/y) = 35 MeV/c2 s(F) = 3.8 MeV/c2 James Ritman Univ. Giessen

  31. PID with DIRC (DIRC@BaBar) GEANT4 simulation for HESR: James Ritman Univ. Giessen

  32. Electromagnetic Calorimeter James Ritman Univ. Giessen

  33. Staged Construction James Ritman Univ. Giessen

  34. Summary • GSI will explore the intensity frontier • High luminosity cooled p-bar from 1-15 GeV/c • Wide physics program including • Charmonium spectroscopy • pbar-A reactions • Search for glueballs and charm hybrids • Panda collaboration forming James Ritman Univ. Giessen

  35. List of participating institutions (incomplete) 40 Institutes (32 Locations) from 9 Countries:Austria - Germany – Italy – Netherlands – Poland – Russia – Sweden – U.K. – U.S. James Ritman Univ. Giessen

  36. Physics with stopped antiprotons 18-19 September 2003 at GSI James Ritman Univ. Giessen