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H(e,e’p) Analysis. Chris Crawford Blast Analysis Meeting 2004/05/21. Monte Carlo Dataset. used DGen, epel channel KINE 10 1. 1. 0. 45. 0. 21. 0. 11. (note .’s) 4 states, q =25 ± 90 ± , f =-17 ± 17 ± gen. 2.5M events ! 1.5M recon (75 bud hrs) momentum resolution: 15 MeV
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H(e,e’p) Analysis Chris Crawford Blast Analysis Meeting 2004/05/21
Monte Carlo Dataset • used DGen, epel channel • KINE 10 1. 1. 0. 45. 0. 21. 0. 11. (note .’s) • 4 states, q=25± 90±, f=-17± 17± • gen. 2.5M events ! 1.5M recon (75 bud hrs) • momentum resolution: 15 MeV • 6th order t2d function (before 2ndq bug-fix) • standard wire resolution (200!120!400 m) • LOSS=1 MULS=1
MC Cross Section theta
Super-ratio Method 2 equations in P, R for fixed bin j independent polarization in each bin! 2n parameters Pj, Rj Global Fit Method fit ALj, ARj to above formalism with P, Rj n+1 parameters n+2 (+spin angle?) same advantage as super-ratio method PbPt still cancels i = left,right j = Q2 bin (1..n) b = spin angle Fit Method
Fit of Spin Angle • Spin angle: 35±§ 10±(errors also insensitive?)
Systematic Errors • 4 measured states ) 2 False Asymmetries • Two options: • a) assume beam and target symmetric, use Ab, At to estimate uncertainty in charge • b) use measured beam/target asymmetryto calculation physics asymmetry dilution
MC Resolution Studies intrinsic wire resolution Momentum Resolution (MeV)
wcb_ntuple.C entry for each stub track info (p,q,f,z) stub coordinates t0-2, x0-2, d0-2 qtrk in cell, B field Tools for Improving Reconstruction/Analysis
Todo List • refine cuts (TOF, CC), subtract background • cuts on epics variables (current, WC HV) • detector efficiencies w/unpol buffer system • more statistics in MC, radiative corrections • unfold b(z), acceptance dependence of s • improve WC resolution, do a kinematic fit • investigate low value of b fit