Hard probes & backgrounds in electron spectrum

• Hard probe contributions to "moderately high pT" electron spectrum:

  • Heavy quarks: open charm & bottom (semi-leptonic decays D ® eX, B ® eX): initial gluon density, energy loss of heavy flavors, baseline for J/Y suppression ...
  • Thermal dileptons, direct photons (via conversion), Drell-Yan.

• Background cocktail contributions to "moderately high pT" electron spectrum:

  • Dalitz decays of p0,h,h’,w,f
  • g conversions
  • Di-electron decays of r,w,f
  • Kaon decays

• Hadron decay generator constrained by measured

• data (p0). mT scaling sqrt(pT2+mh2-mp02) for other

• hadrons (measured K±, p, pbar agree within 20%).

• Particle ratios at high pT from fixed target data:

• h/p = 0.55, h’/p = 0.25, r/p = w/p = 1.0, f/p = 0.40.

• Conservative syst. error of 50% to these ratios

• Photon conversion background from beam pipe and

• MVD: GEANT simulation + hadron decay generator