Physics with open charm Andrey Sokolov IKP I FZ Jülich
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.
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 00 11 00 11 22 22 DsDs Ds*Ds* D sJ * (2317) D s1 m [GeV/c 2 ] D0KD0K D*K D sJ (2458) D s2 * JPJP
May 19, 2005 Andrey Sokolov 4
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)
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 = (0,1,2) (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 ] 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 P lab [GeV/c]
May 19, 2005 Andrey Sokolov 7 PANDA Detector
May 19, 2005 Andrey Sokolov 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
May 19, 2005 Andrey Sokolov 9 Reconstruction of D and D s mesons DecayBr, %Efficiency, % * * Only one kaon identification is required.
May 19, 2005 Andrey Sokolov 10 Simulation of Ψ(4040) Simulate 5 days data Initial S/B ratio Simulated S/B ratio 3 The reaction have been studied Invariant mass difference between D *± and D 0 mesons Ψ(4040) invariant mass distribution
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.
May 19, 2005 Andrey Sokolov 12 D * -decay Momentum vs. polar angle distribution of decay product from reaction