For the pair production efficiency study, I applied a timing cut between the veto and the tagger's photon. The efficiency is 78%. Here is the timing difference spectrum with my cut limits in red.
In the next figure, I plotted the Veto counter ID vs the time difference between the Veto and the photon in the tagger. There is a small misalignment between the individual counters.
I plotted the tagger T-channel number vs the time difference between the Veto and the photon in the tagger. It is clear that I am using the wrong tagger calibration constants.
I reanalyzed run 4865 with the new tagger timing constants. The results are below.
Below are two plots of the HYCAL trigger TDCs for the horizontal and vertical strips. The left plot is raw TDC channels and the right plot is a rough conversion to time.
Below are two plots of the HYCAL time vs trigger bit. The left and right plots are from HTRIGT TDC channels 1 and 7, respectively.
Hycal total energy sum for pair production run.
