V0 Reconstruction

Last updated: March 01, 2002

Data Samples

• p10.14 root tuples. Dataset definition: "d14"

V0 Finding Algorithm

• Ntuple block "V0": Kalman Filter constrained vertex fit of all pairs of SMT tracks.

K0 Selection

• opposite charged tracks
• vertex chi2 < 15
• colinearity angle (p.l) > 0.9999
• decay length (l) > 0.35cm (with respect to nominal IP = (-0.024, -0.0489)cm)
• vertex radius < 2.6cm (first SMT layer)
• track impact parameter > 0.1cm
• track transverse momentum > 0.3 GeV/c
• Mass fit to double Gaussian + background, fit parameters are from Narrow Gaussian

• invariant mass
• Note: K0 PDG mass=0.4976 GeV

Lambda Selection

• opposite charged tracks
• vertex chi2 < 15
• colinearity angle (p.l) > 0.9999
• decay length (l) > 1.0cm (with respect to nominal IP = (-0.024, -0.0489)cm)
• vertex radius < 2.6cm (first SMT layer)
• track transverse momentum > 0.3 GeV/c
• highest pT track assigned to proton
• Vetoed events where pi-pi mass consistent with K0 mass
• Mass fit to single Gaussian + background

• invariant mass with fit parameters
• Note Lambda PDG mass=1.1156 GeV
• Note Lambda Peak ~3 sigma significance