D and D* peaks in CLEO III (without SVX info, yet!)

Results from 72 pb^-1 (66 large runs).

Track filter:

• Kalman fit OK and chi2/ndof < 3.5
• # hits on track/# expected > 0.7
• |d0| (=DBCD) < 3 cm
• |z0| (=Z0CD) < 15 cm
• |momentum| > 100 MeV
• Sufficient z information (DR stereo layers and cathodes only --- no SVX):
• sigma(z0) < 50 cm
• sigma(cotTheta) < 1
• |cosTheta| (=CZCD) < 0.9 cm

Events selected using AJW's EVCLAS hadronic criteria: ICLAS=10 or 11, JCLAS=1:

• Not gamma-gamma or bhabha (including radiative)
• # charged tracks > 3
• Visible energy > 0.4 E_cm
• Energy in CC > 0.15 E_cm
• No event vertex requirements

D->Kpi cuts:

• |p_D| > 1.7 GeV (no further need to require asymmetric pion and kaon momenta)
• dE/dx consistency: 2.5 sigma for pions, 3.3 sigma for kaons
• Yield = 1106 events => eff ~ 30%

|m_D* - m_D|:

• |p_D| > 1.2 GeV
• |p| of slow pion < 500 MeV
• dE/dx consistency: 2.2 sigma for pion from D, 3.2 sigma for kaons, 4.0 sigma for slow pion
• |cosTheta| of event thrust axis < 0.95

D*-tagged D:

• Above deltaM cuts and |m_D* - m_D| < 150 MeV
• Yield = 164 events => eff ~ 10% => slow pion eff ~ 35%

Please send comments to Werner Sun (wsun@mail.lns.cornell.edu)