Upsilon L2 triggered events analysis and the BEMC Preshower

This is a brief status report on inculding the preshower in the Upsilon analysis

We have used online pedestals for mimicking the triggers, today we will briefly study the L0 trigger and how much remians after cuts

We worked with the L0 trigger for a small sample of the Upsilon data in this study and wanted to investigate where the triggered events "get lost".

Using primarly Vertex Only we mimicked the L0 trigger from the ADC values by bitshifting the ADC by 4: ADC>>4 > 18.

We then made track assocaitions to the towers. The tracks were extrapolated to the center of the tower to improve the resolution

We investigated to see if there were any obvious hot tower cluster, this was not found to be the case, the towers look pretty well distributed

Double counting

We then investigated the number of times a track pointed to the same tower after passing the L0 mimic

this leaves (724-195)/2190= 24% of tracks passing the mimic

It was found that the additon of a momentum cut, of at least p>1, reduced the amount of towers with double tracks passing the mimc trigger

This gives (450-2)/2190= 20%

Are there still false associations or tracks pointing to photon clusters? Making the PID cuts as well as tighter cuts on P should help eliminate these

dEdx and the preshower

The Dedx cut leaves of 3e-6 to 5e-6 leaves 212/2190= 10%

We are using a lose cut for now, as the L0 mimc was very sensative to the width of this selection

With the preshower and all other cuts we are left with 79/2190= 4%

No preshower, dedx, p>1 and mimc

Preshower, no dedx, all PID, p>1 and mimc

Preshower, dedx, all PID, p>1 and mimc



Next time we will show some results from the study of the preshower on the paired events