User name ulmer
Log entry time 10:31:37 on November 2,2002
Entry number 89461
keyword=tails in right arm ph_tg, th_tgThe figure shows an analysis of run 2916 (kin Q3D_f40r) for the uncut Ntuple (all event types). The histograms show the total spectrum, the spectrum which pass the A1 aerogel cuts and the spectrum which fails for both theta and phi at the target for the RIGHT arm. The A1 cuts are defined as events with "rbig" (failed A1) and the negation of this cut (passed A1). It can be seen that the failed events, which should correspond to protons, have significantly less tails. Though they're not shown here, the coincidence spectra have essentially no tails. Perhaps the tails are coming from pion decay in flight resulting in events which hit the VDC's but with screwy tracks. It may also be that some of the failed events for A1 are simply those which entirely miss the counter. These events would then be interpreted as protons even though they are not and therefore a remnant of these tails would remain (as seen in the figure). This is just theory, but at least these nasty tails seem to be related to pions.
FIGURE 1
