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Investigating methods to improve pi0 energy resolution by minimizing chi-square with mass constraint in final state reconstruction. Analysis includes usage of start position variable, true hit position calculations, and comparison of directional information from true and reconstructed data.
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reconstruction in final state Jaewon Park University of Rochester MINERvA/Jupiter Group Meeting, June 13, 2007
Enhance pi0 energy resolution using chi-squire minimization with pi0 mass constraint • I used startpos variable in recon ntuple block but I haven’t check how it was calculated. • While reco dir is calculated from reco proton vertex and center of gamma energy, center of gamma energy is calculated with true hit position. • Reco direction is calculated using too much true information.
Angle between two gammas • RMS function will be determined from single pi0 particle event with each energy (theta=0deg) • Kevin suggested RMS function of angle • Longitudinal vertex resolution is bigger than transverse res • 0.67cm, 0.31cm respectively
2-dimensional chi-square fit: including angle (1) True angle, no chi-square (2) True angle, chi-square(E) fit (3) Reco angle, chi-square(E) fit (4) Reco angle, chi-square(E, angle) 1 2 • (3) is expected bigger than (2) • (4) is not much different from (3) true dir true dir + fit 3 4 reco dir + fit reco dir + fit