J/Psi in di-electron channel

1. J/Psi in di-electron channel Alla Maevskaya Institute for Nuclear Research RAS, Moscow CBM collaboration meeting 11 March 2005 GSI Darmstadt

2. Outlook • For Au+Au 25AGeV collisions • J/Ψ momenta and rapidity spectra • Background sources • Simulation in different conditions: • pion suppression factors • applying different Pt cuts • applying different mass resolution • For central and mbias collisions • For different beam energies • Conclusions Alla Maevskaia INR RAS Moscow CBM collaboration meeting 11 March 2005

3. Au+Au 25AGeV: Transverce momenta and rapidity distribution for J/Psi mesons. • all J/ψ • accepted in detector • with Pt >1GeV/c Calculations was done by PLUTO for generation J/ψkinematics and cbmroot version OCT04 for transport. J/ψ multiplicity was obtained according HSD predictions Alla Maevskaia INR RAS Moscow CBM collaboration meeting 11 March 2005

4. Au+Au 25AGeV central:Tranverse momenta distribution for e+e- from different background sources Background electrons from γ, π0, η & misidentified charged pions (suppression 10-4) were obtained from UrQMD generator + cbmroot vOCT04, STS + RICH +TRD in, field "FIELD.v04_pavel.map" open charm was calculated by V.Friese code by Goran; J/ψ momentum distribution - by PLUTO, multiplicity – by HSD Alla Maevskaia INR RAS Moscow CBM collaboration meeting 11 March 2005

5. Au+Au 25AGeV central:invariant mass spectra for 2x1010 events with cut Pt>1GeV and different pion suppression factors : 10-2; 10-3;10-4 ; no pions ψ For pion suppression 10-4 and different Pt cuts Alla Maevskaia INR RAS Moscow CBM collaboration meeting 11 March 2005

6. Au+Au 25AGeV central Invariant mass spectra for different mass resolution scenario Pt > 1GeV/c 90 MeV J/ψ mass resolution 30 MeV 150 MeV Pt > 1.3 GeV/c Alla Maevskaia INR RAS Moscow CBM collaboration meeting 11 March 2005

7. Au+Au 25AGeV mbias Invariant mass spectra for different mass resolution scenario Pt > 1GeV/c 5% -150 MeV Pt > 1.3 GeV Alla Maevskaia INR RAS Moscow CBM collaboration meeting 11 March 2005

8. Au+Au 25AGeV : Signal /Background ratio dependance on mass resolution, Pt cuts and centrality Alla Maevskaia INR RAS Moscow CBM collaboration meeting 11 March 2005

9. Signal/Background and J/Psi efficiency for central Au+Au collisions at 15, 25 and 35 AGeV Alla Maevskaia INR RAS Moscow CBM collaboration meeting 11 March 2005

10. To be done : “realistic” J/ψ generation using HSD and PYTHIA Investigation of ψ' ??? Centrality dependence of the statistical significance Normalisation of J/ψcross section ??? Using reconstructed tracks for signal and background calculations