1. New Opportunities for Hadron Physics with the Planned PANDA Detector
Overview of the PANDA Physics Program
The PANDA Detector
Selected Simulation Results
Charmonium: EM decays
Charmonium: Open charm decays
Charmonium in nuclear matter
James Ritman Univ. Giessen

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

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

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

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

6. James Ritman Univ. Giessen
High Resolution
Crystal Ball: typical resolution ~ 10 MeV
Fermilab: 240 keV
 p/p < 10-4 needed
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7. James Ritman Univ. Giessen
Open Questions
c (11S0) (Simu results) experimental error on M > 1 MeV G hard to understand in simple quark models
c’ (21S0)
Crystal Ball result way off study of hadronic decays
hc(1P1)
Spin dependence of QQ potential Compare to triplet P-States LQCD  NRQCD
James Ritman Univ. Giessen

8. James Ritman Univ. Giessen
Open Questions
States above the DD threshold Higher vector states not confirmed Y(3S), Y(4S) Expected location of 1st radial excitation of P wave states Expected location of narrow D wave states Only Y(3770) seen Sensitive to long range Spin- dependent potential
(Simu results)
James Ritman Univ. Giessen

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

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

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

12. J/Y Absorption in Nuclei
J/Y absorption cross section in nuclear matter
p + A  J/Y + (A-1)
(Simu results)

13. Comparison of p-A Reactions to A-A
Much lower momentum for heavy produced particles (2 GeV for “free”) (Effects are smaller at high momentum)
Well defined nuclear environment (T and r)
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14. The Experimental Facility
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15. HESR

16. HESR: High Energy Storage Ring
Beam Momentum 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

17. James Ritman Univ. Giessen

18. James Ritman Univ. Giessen

19. Central Tracking Detectors
MVD: (Si) 5 layers
~ 9 Mio pixels
Andrei Sokolov HK39.5
Thursday 15:00
Straw-Tubes
Mini-Drift-Chambers

20. James Ritman Univ. Giessen
PID
ToF
Muon Detectors
DIRC
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21. James Ritman Univ. Giessen
Open Charm
pp DD
DKpp
„no background events added“
Mass Resolution
~ 10 MeV/c2
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22. Vertex Distributions GEANT4
Transverse
D meson signal DPM background
signal DPM background
Scale up by x10!
0.15 < Vz < 5 mm
Longitudinal
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23. James Ritman Univ. Giessen
DD Missing Mass
signal DPM background
N.B. different x scale
| Mmiss 2|< GeV2 (tight cut)
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24. James Ritman Univ. Giessen
Open Charm
As an example of the Pbar P  Y(3770)  DD Analysis
Plot MDD – MD – MD + 2x1869MeV
raw S/B ~ 10-7
James Ritman Univ. Giessen

25. Detection of Rare Neutral Channels
As an example: hcgg Background: p0g, p0p0
hc:p0g:p0p0 1:50:500
Comparison with E835
(PLB 566,45)
PANDA
James Ritman Univ. Giessen

26. Dimuon Spectrum in p+Cu
Beam momentum “on resonance”
Full background simulations (result scaled up)
Muons from J/Y have high Pt
J/Y has low Pt (coplanar)
J/Y
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27. James Ritman Univ. Giessen
Summary
GSI will explore the intensity frontier
High luminosity cooled p from 1-15 GeV/c
Wide physics program including
Charmonium spectroscopy
pbar-A reactions
Search for glueballs and charm hybrids
James Ritman Univ. Giessen

28. James Ritman Univ. Giessen

29. James Ritman Univ. Giessen
In part supported by:
GSI
BMBF 06GI144
DFG
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30. James Ritman Univ. Giessen
Target
A fiber/wire target will be needed for D physics,
A pellet target is conceived:
1016 atoms/cm2 for D=20-40 mm
1 mm
James Ritman Univ. Giessen

31. Electromagnetic Calorimeter
Detector material
PbWO4
Photo sensors
Avalanche Photo Diodes
Crystal size
 35 x 35 x 150 mm3 (i.e. 1.5 x 1.5 RM2 x 17 X0)
Energy resolution
1.54 % / E[GeV] %
Time resolution
s  130 ps (N.B. with PMT!)
Total number of crystals
7150
James Ritman Univ. Giessen

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

33. James Ritman Univ. Giessen
Staged Construction
James Ritman Univ. Giessen

34. Pbar-Nucleus Interactions
The interaction of charmed mesons
with the baryonic environment
strongly effects production rates
near threshold
James Ritman Univ. Giessen

35. 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 X-
3 GeV/c
Trigger p _ X
secondary target
X-(dss) p(uud)  L(uds) L(uds)

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

38. James Ritman Univ. Giessen
Open Questions
The c(11S0)
The c(21S0)
The hc(1P1)
States above the DD threshold
James Ritman Univ. Giessen

39. Proton Form Factors at large Q2
At high values of momentum transfer |Q2| the system should be describable by perturbative QCD.
Due to dimensional scaling, the FF should vary as Q4.
The time like FF remains about a factor 2 above the space like. These differences should vanish in pQCD, thus the asymptotic behavior has not yet been reached at these large values of |q2|.
(HESR up to s ~ 25 GeV2)
q2>0
q2<0
James Ritman Univ. Giessen

40. 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  c + h
James Ritman Univ. Giessen

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

42. James Ritman Univ. Giessen
Exotic Hadrons
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43. James Ritman Univ. Giessen
Glueballs
C. Morningstar PRD60, (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-+,... g
1GeV=32pt
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44. James Ritman Univ. Giessen
Charm Hybrids ccg
Prediction in QCD:
Collective gluon excitation
(Gluons contribute to quantum numbers)
Ground state: JPC = (spin exotic)
distance between quarks
James Ritman Univ. Giessen

45. James Ritman Univ. Giessen
Partial Wave Analysis
Partial wave analysis as important tool
Example of 1-+
pd  X(1-+)+p+p, X  h p
Strength ~ qq States !
Signal in production but not in formation is interesting !
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46. James Ritman Univ. Giessen
Quark Condensate
The QCD vacuum is not empty
Hadron masses are generated by the strong
interaction with <qq> (also with gluon 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

47. 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).

48. Deeply Bound Pionic Atoms
Pionic capture is possible with the appropriate choice of kinematics:
d+n  3He + p-
These results indicate a mass shift of ~25 MeV for pions at normal nuclear matter density.
James Ritman Univ. Giessen

49. Kaons in Nuclear Matter
Kaon and anti-kaon masses should no longer be degenerate in nuclear matter.
Expected signal: increased K- production compared to K+.
J.Schaffner-Bielich et al., Nucl. Phys. A (1997) 325.
James Ritman Univ. Giessen

50. Measured K- Cross Section
Comparison of proton-proton data with heavy ion data[2]:
dramatic enhancement of the K- production probability
KaoS
[1] A.Sibirtsev et al., Z.Phys. A358 (1997) 101.
[2] F.Laue et al., Phys.Rev. Lett. 82 (1999) 1640.
[3] C.Quentmeier et al., Phys Lett B 515 (2001) 276.
James Ritman Univ. Giessen

51. James Ritman Univ. Giessen
Open Charm in Nuclei
The interaction of charmed mesons with the baryonic environment strongly effects production rates near threshold
James Ritman Univ. Giessen

52. cc Production in Nuclear Matter
The mass of charmonium states is not expected to change much.
However, a drop of the DD mass leads to a widening of the cc
states.
Y’ will have too high
momentum, most decay
outside.
 but wider tails
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53. James Ritman Univ. Giessen
Charmonium in Nuclei
Due to the increased width, the dileptons from charmonium states below the free DD threshold are strongly suppressed.
Golubeva et al. Eur.Phys.J. A17 (2003)
James Ritman Univ. Giessen