1. Physics with open charm mesons @ Andrey Sokolov IKP I FZ Jülich

2. May 19, 2005 Andrey Sokolov 2 PANDA Physics program  Charmonium spectroscopy: –Precision M and Γ measurement, error and qq – potential. –Open charm physics.  Search for the charmed hybrids, glueballs.  Study of modifications of the meson. properties in the nuclear medium.  Hypernuclear physics.

3. May 19, 2005 Andrey Sokolov 3 The D S ± spectrum |cs> + c.c. was not expected to reveal any surprises, but... –Potential model –Old measurements –New observations (BaBar, CLEO-c, Belle) Or these are molecules? New observations 00 11 00 11 22 22 DsDs Ds*Ds* D sJ * (2317) D s1 m [GeV/c 2 ] D0KD0K D*K D sJ (2458) D s2 * JPJP

4. May 19, 2005 Andrey Sokolov 4

5. May 19, 2005 Andrey Sokolov 5 Depend on internal structure the width of D sJ * can be different: → Current limit  4.9 MeV →  -doubling  10 keV → Phenomenological  130 keV → D s K – molecules  200 keV Threshold production of D sJ * (2317)

6. May 19, 2005 Andrey Sokolov 6 Charmonium Physics D DD*DD* ψ(1 1 D 2 ) ψ(1 3 D 1 ) ψ(1 3 D 3 ) ψ(1 3 D 2 ) η c (2 1 S 0 ) D* D * ψ(2 3 S 1 ) J/ψ(1 3 S 1 ) ψ(3 3 S 1 )  c2 (1 3 P 2 )  c0 (1 3 P 0 )  c1 (1 3 P 1 ) h 1c (1 1 P 1 )  c0 (2 3 P 0 )  c1 (2 3 P 1 )  c2 (2 3 P 2 ) h 1c (2 1 P 1 ) η c (1 1 S 0 ) η c (3 1 S 0 ) J P =0 - 1-1- 1+1+ (0,1,2) + 2-2- (1,2,3) - Are ψ(4040) and ψ(4160) strong mixtures of the Ψ(3S) and hybrid charmonium states or ψ(4040) is D * D*- molecule? 2.9 M c c [GeV/c 2 ] 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 ψ(4 3 S 1 ) X(3872) D sJ *D sJ * Is the narrow X (3872) state D 0 D* molecule? Most states above DD not measured Measure decay branching ratios. 3.4 4.1 4.8 5.5 6.3 7.1 8.0 9.3 10.3 P lab [GeV/c]

7. May 19, 2005 Andrey Sokolov 7 PANDA Detector

8. May 19, 2005 Andrey Sokolov 8 1000 decays were simulated:  Here D-mesons decayed at the point (0.1,0.1,0.4)mm.  Kaon ID was required.  Three tracks were refitted to the common vertex. Simulation of the D-mesons Invariant mass of D - mesonVertex position

9. May 19, 2005 Andrey Sokolov 9 Reconstruction of D and D s mesons DecayBr, %Efficiency, % 9.227 3.831 7.520 4.4 30 * * Only one kaon identification is required.

10. May 19, 2005 Andrey Sokolov 10 Simulation of Ψ(4040)  Simulate 5 days data  Initial S/B ratio  10 -8  Simulated S/B ratio  3 The reaction have been studied Invariant mass difference between D *± and D 0 mesons Ψ(4040) invariant mass distribution

11. May 19, 2005 Andrey Sokolov 11 Summary  There are many open questions for open charm and charmonium above the DD threshold.  The PANDA experiment will be an excellent tool to answer these problems.  Good reconstruction efficiency for many types of D-mesons has been demonstrated.  Very high background suppression is achieved.

12. May 19, 2005 Andrey Sokolov 12 D * -decay Momentum vs. polar angle distribution of decay product from reaction