Single Lepton Identification and Close Pair Recognition in the HADES RICH *
March 29, 2002
The fast RICH of the new dilepton spectrometer HADES serves as a hadron
blind trigger device for e+e- pairs in hadron and heavy ion induced collisions in the
1-2 A GeV incident energy range. Dalitz decays of abundantly produced π0s
and external conversion of high energetic photons in target and radiator
(C4F10) are the main sources of e+e-
pairs with small opening angles (1-15 degrees). Double rings from such close pairs, if not properly identified and separated,
lead to tremendous combinatorial background and screen the physics signal of interest.
*supported by BMBF (6TM970I) and GSI (TM-FR1).