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Hi Brad, I don't think that such a cut is statistically correct. Imagine that we have symmetric decay: E1=E2=Ebeam/2. Due to the final resolution we will have after reconstruction: 1. 25% of the events E1<Ebeam/2 and E2<Ebeam/2 --- you will reject these events 2. 25% of the events E1>Ebeam/2 and E2>Ebeam/2 --- you will reject these events 3. 25% of the events E1<Ebeam/2 and E2>Ebeam/2 --- you will accept these events 4. 25% of the events E1>Ebeam/2 and E2<Ebeam/2 --- you will accept these events Due to your cuts you will throw away events 1) and 2) and will accept 3) and 4). You will reject 50% ABSOLUTELY GOOD EVENTS. In such a way you can create dip in ANY distribution. I would like to bring to your attention that you have dip in MC events without this cut. I still have a question: are you going to present your MC analysis without trigger cuts? Regards, Valery > > On May 19, 2016, at 23:29, Bradley T Yale <[log in to unmask]> wrote: > >> I think the mystery of the Moller gap has finally been solved. >> >> Looking at the reconstructed Moller events generated with the fixed cross >> section, not much was changed, >> so I explicitly forced the condition such that if one Moller had track E > >> Ebeam/2, then the other had to have E < Ebeam/2, and vice versa. >> >> Applying this to both MC and Data, along with modest ESum and phi cuts, gives >> the attached momentum plots. >> The other distributions match much better too, particularly track position at >> the ECal, which now shows the gap in data as well. The higher-energy bias for >> hits in the bottom half of the ECal can be seen from the asymmetry in where the >> electrons hit. Loosening the MC cuts a little (only cutting ESum) starts to >> close the gap and make it look even more like the data plots. >> >> So in summary, the gap is likely due to electrons always being cleanly paired on >> opposite halves of Ebeam/2 in MC, but not necessarily in data. The gap is also >> apparent in background MC without forcing this condition, suggesting that the >> MC is too "clean". >> -Brad >> >> >> Use REPLY-ALL to reply to list >> To unsubscribe from the HPS-SOFTWARE list, click the following link: >> https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=HPS-SOFTWARE&A=1 >> <MC_TRACK_Energy.png><MC_tracksAtEcal.png><DATA_TRACK_Energy.png><DATA_tracksAtEcal.png><LOOSERMC_TRACK_Energy.png><LOOSERMC_tracksAtEcal.png> > > ######################################################################## > Use REPLY-ALL to reply to list > > To unsubscribe from the HPS-SOFTWARE list, click the following link: > https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=HPS-SOFTWARE&A=1 ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the HPS-SOFTWARE list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=HPS-SOFTWARE&A=1