Re: [BLAST_ANAWARE] bad proton momenta

From: Eugene J. Geis (Eugene.Geis@asu.edu)
Date: Mon May 17 2004 - 05:48:06 EDT


TB and other recon and Hydrogen people,
  Ran some comparisons between last year's H2 inbending runs and this year's and
looked for some characteristic differences. The data seems to point to a flip
in the particle-specific momentum and chi^2 distributions. For the proton, it
used to escalate from ~0.02 to a sharp peak at ~0.005 and now it has a long hump
that stretches from 0.02 through 0.1 (please see prot_X2.ps, last years runs are
in RED, this year's in BLACK). Now, when we look at the electron's X2
distributions... the opposite has happened. It used to run from 0.005 and
linearly decline beyond 0.2, now it begins to escalate from ~0.1 through to
~0.01 (please see elec_X2.ps, last year in RED).

  When taking these results and now looking at Momentum and Momentum vs. Theta
(prot_mom.ps and prot_theta.gif), we get a broadened range for the proton
momentum vs. proton theta from last year to this year (same color
identification). The RED is much tighter in the 2D plot. In the 1D plot of
proton momentum all that can be said is that there are more low-momentum protons
this year. Now, looking at the electrons, we see the opposite effect... The
BLACK (electrons from this year) are much tighter than the RED in the 2D plot
(elec_theta.gif) and this is much more apparent in the 1D plot
(elec_mom.ps) of the electron's momentum.

This seems to point to some kind of favoring of treatment of charge or maybe a
weighted fitting to tracks curving in opposite directions that switched from
last year to this year.

These are all for Electron_R and Proton_L reactions... YES, I checked: The data
relationships do not change from switching sector.

Last Year's RUNS used in this analysis: 2018-2024 2026-2030 2037 2039 2041-2044
2047 2048 2050 2052-2053 2055-2060 2109-2113 2115-2117
Elastic Events surviving these TIGHT ep cuts:3579
EP_elas_tight_eR + trig==1

This Year's RUNS used: 6504-6509 6511-6513 6517-6523
Elastic Events surviving these TIGHT ep cuts:3410
EP_elas_tight_eR + trig==1

In summary, I think our bad electron momentum from last year has somehow become
our bad proton momentum this year. This is NOT to say that electron momentum is
wonderful since our very forward angle scattered electrons still have quite a
width... the plots speak for the change in the reconstruction.

eugene

Quoting Tancredi Botto <tancredi@lns.mit.edu>:

>
>
> Eugene, I also get very bad results for this run years. You can see
> numberic summary results in users/tancredi/results/Res for various run
> numbers. Since the electron seems fine, I wonder if it is a feature of
> our
> configuration rather than a new bug in the codes
>
> I've also attached
>
> diff ~/pro2004/Blast_Params/blastrc
> /home/blast/blast/cvs_v2/Blast_Params/blastrc
>
> It may be worthwhile to run with the
>
> a) same blastrc of last year (where possible)
> b) same code of last year (see ~/lib/libBlast.so.2.96b)
>
> Do we see a difference between these two data sets in the (various) cell
>
> plots discussed wednsday ?
>
> --
> ________________________________________________________________________________
> Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124
> research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>

--------------------------------------------------------------------------
Eugene Geis
PhD Student, Physics Department, ASU
Research Affiliate, MIT-Bates Laboratory of Nuclear Science
eugene.geis@asu.edu
--------------------------------------------------------------------------
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elec_theta.gif





prot_theta.gif



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