Charmed Hadrons in Matter

1. Charmed Hadrons in Matter • Introduction • Medium Effects in the light quark sector • Expectations for the charm quark sector • J/ψ-N interaction • Requirements for the Experiment • Conceptual Design • Conclusions Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI

2. Introduction Origin of Hadron Masses ? Chiral Symmetry in QCD is spontaneously broken Mass Modifications due to • Chiral Dynamics • Partial Restoration of C.S. in Hadronic Environment Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI

3. Deeply bound Pionic States • 206Pb(d,3He)Pion-Nucleus Potential from binding energy and width isospinasymmetric matter, ρ ρ0m(π-) increased by 25 MeV A. Gillitzer, Hirschegg ‘01 Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI

4. Production of Open Strangeness • Excitation functionfor K+/K- productionin H.I. Reactions • Different from elementary reaction:enhanced σ(K-) • K- mass loweredby  100 MeV (ρ  ρ0) F. Laue, EPJ A9 397 Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI

5. Expectations for charmed Mesons • J/ψ, ηc: -5 to -10 MeV • D-Mesons“Hydrogen of QCD”- mass lowering- 50 MeV mass split Charm quark mass: 1.3-1.5 GeV Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI

6. Consequences for Observables • DD production will be enhanced below threshold • D-mesons decay semi-leptonic (10-20% BR) • Cross sections 1 nb near threshold A. Sibirtsev EPJ A6 351 • D,D,Ds,Ds,J/ψ,ψ’ Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI

7. Consequences for Observables II • Threshold lowered by  100 MeV “new” decay channels open (ψ’,χc2)  width increases • ψ(3770) broadening(lepton pair detection) A. Hayashigaki PLB487 96 Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI

8. J/ψ-N Absorption Cross Section • In URHIC: suppression of J/ψ observed • Hadronic Interactions? • 3-4 mb from γN6-7 mb from pA, AA • Antiproton annihilation on nuclei • also for J/ψ, ψ’, χJ on various nuclear targets K.K. Seth, Hirschegg ‘01 Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI

9. Dissociation of Charmonium • p + d  D- + Λc+ • cc interacts with residual neutron • Studying energy dependence A. Sibirtsev NPA680 274c • p + d  J/ψ + g + n: measuringσ(J/ψ-N)elastic down to lower relative momenta • J/ψ -meson scattering cross section Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI

10. Requirements for the Experiment • Production of charmed mesonsσ(DD)  1 nb  100 d-1 @ L = 2·1031 cm-2s-1 high luminosity • ct(D±) = 315 µm, ct(DS) = 149 µm well-defined interaction point good vertex resolution (  100 µm ) • D’s decay semileptonic (10 – 20 % B.R.)decay kinematics: high pt, large opening angles  momentum determination, PID Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI

11. Microvertex Tracking Silicon Pixel Detector, 200 µm wafers (0.25% X0) 7.2 MPixels 50·300 µm² 2 MPixels 100·150 µm² Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI

12. Microvertex Tracking II Does the concept meet the requirements? s(DZ0) = 85 µm s(DD0) = 50 µm Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI

13. Momentum determination, PID • Straw Tubes for trackingσxy = 150µm, σz = 1mm • Drift chambers • Separation of π/K (DIRČ) Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI

14. Lepton identification • Electromagnetic calorimeter (PbWO4) 96% coverage of the solid angle • Muon hodoscope(plastic scintillators) Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI

15. Conclusions • GSI has a successful history in studying medium effects in the light quark sector • Extending the program to the charm quark sector promises exciting perspectives • The proposed program requires a versatile detector in terms of resolution, PID, rate capability and triggering Workshop on Experiments with Antiprotons at the HESR – April 2002, GSI