Hello folks,
I have been investigating the problem reported by Daniele in
http://www.slac.stanford.edu/cgi-bin/lwgate/VUB-RECOIL/archives/vub-recoil.200211/Author/article-35.html
i.e. that there was a significant change in the result (and therefore in
the mxhad agreement) between different photon selections.
I have been checking the mean value of the number of neutrals (nneu) for
events with p*>1 and in the depleted sample, in order to understand which
cuts had the biggest impact on the sample of neutrals.
Hera re the results:
selection <nneu>
egamma> 50 MeV 4.75
-------------------
egamma> 50 MeV 3.99
acceptance (theta>0.41)
-------------------
egamma + acc 3.93
S9S25>0.9
-------------------
egamma+acc+S9S25 3.39
lat>0.05&&lat<0.5
It looks like the biggest impact comes from the acceptance, which should
remove only 10% if it were space phace, but it removes much more.
I have therefore tried out trk7 gam7 (i.e. all cuts including the
unmatched clusters removal) having removed the acceptance cut and called
it trk7 gam8.
The comparison plots are in
http://www.slac.stanford.edu/~rfaccini/phys/vub/comp_110602B0-trk7gam8/-comp.html
and
http://www.slac.stanford.edu/~rfaccini/phys/vub/comp_110602Bch-trk7gam8/-comp.html
there is no striking improvement
ciao
ric
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