Open charm spectrum from the electron data

• Background subtracted single electron spectra:

• Open charm contribution (scaled pp PYTHIA)

• PYTHIA 6.152 parameters:

• CTEQ5L, Mc=1.25 GeV, K=3.5, <kT>=1.5 GeV/c

• s(pp ® cc) = 330 mb @ 130 GeV

• Fixed target charm data (SPS, FNAL) & ISR single electron data reproduced.

• Other signals:

  • b-decays: significant only at higher pT [PHYTIA estimate]
  • Drell-Yan, J/Psi decays: negligible compared to charm [PHYTIA]
  • Thermal di-leptons: r ® ee contribution <1% of background. Large contribution from pp ® r ® ee (dominant source of low mass pairs) unlikely. [R.Rapp, next slide]
  • Direct photons (conversion): Can contribute 10-20% to the signal. Large uncertainties in theoretical predictions. [Estimation: J.Alam, next slide]