[BLAST_ANAWARE] minutes meeting 4/28

From: Tancredi Botto (tancredi@lns.mit.edu)
Date: Wed Apr 28 2004 - 12:07:01 EDT


_ Two of the most urgent problems from last weeks (ed, mc recon)
  have been promptly solved. Found bug affecting reconstruction

_ t2d/recon problems
        _ found that t2d was invoked with track angle in radians
          when deg was expected
        _ When this is accounted for dp, dth, dph, dz worsen by ~ 50%
        _ Not understood. Could be recon problem, could be t2d
        _ Problem only with data, montecarlo recon fine now
        _ it looks bad also with older 3rd order parametrization
        _ need to make sure we use same definition of track angle !
        _ Montecarlo uses d2t (inverted from garfield t2d), generates TDC
          and then uses garfield t2d in recon, so effectively a "bad" t2d
          will cancel in montecarlo
        _ Is the recon speed mc/data different ?
        _ Also, selecting only linear region yields same momentum uncertainty (5%)
        _ Could there be more bugs ... ? discussion on retiming

_ ed
        _ ed yields miisng becuase of bad chi2 cut
        _ remaining L,R differences 10% sitll investigating
        _ ed vector asymmetry : no report, PK busy

_ eep Pz vs Pzz
        _ QE Analysis determines Pz, Pzz not P1, P2
        _ Pzz determined in 3 independent ways. lower than Pz
        _ Unlikey QE Pz is right, Pzz is wrong
        _ Still Pzz 0.5 and Pz 0.75 why ?
        _ Would require simultaneous inefficiency of MFT14 and SFT35
          of the order of 20 % assuming only T=-2 state wrong
                _ Note these transitions unique to T=-2 state
        _ Problem with DGen input ? responses ?
                _ Note DGEN input if response f's, no P1, P2 ambiguity there
        _ Maybe beam pol too low
                _ Note value would need to be 97.5 !! (from 65 %)
                 _ of course could account for part of discrepancy
        _ Will compare to eep data in NIKHEF acceptance

_ Singles
        _ NM shows D2 spectrum and asymmetry (only in Delta region)
        _ currently comparing H2 singles with montecarlo
        
_ montecarlo
        _ Nice tip from CC: switch off random wch hits to speed up
          recon (note this feature is not used right now)

_ oba
        _ TA has a script for DVD backups. Will send instructions

_ recrunch
        _ TDC offsets (tof, neutron) not ready, t2d bug not fixed
        _ code being tested
        _ will focus only on subset of data initially

-- 
________________________________________________________________________________
Tancredi Botto,  		phone: +1-617-253-9204  mobile: +1-978-490-4124
research scientist		MIT/Bates, 21 Manning Av    Middleton MA, 01949
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