In Vitaliy's shift summary, elog 6690, he described using Cerenkov cuts
to reduce the unpolarized background. In his results, the relatively
new graphical cuts "lcut" and "rcut" were also used. The combined
Cerenkov cuts and graphical cuts do significantly improve the left and
right asymmetry. They also make the fitted (Pol_beam*Pol_targ)
parameter closer to equal between sectors. His results were:
left dilution right dilution
no cc 0.13 0.09
cc_el 0.16 0.14
The graphical cut is a cut on Theta_el and Theta_p for elastic
kinematics. I have attached results for applying neither cut, the
graphical cut, the Cerenkov cut, and both the graphical and Cerenkov
cut. The results for almost the same data set (2201-2365) are:
no_cut 0.12 0.07
graph_cut 0.13 0.08
Cer_cut 0.15 0.13
both_cuts 0.16 0.13
It is clear that the Cerenkov cut improves the asymmetry more than the
graphical cut. Both cuts are now in the macro "show_ep_asym2.C".
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