Bartender accidental pileup in signal region

1
Bartender - accidental pileup in signal region

• Introduced rotation of Michel positrons for
  efficient simulation of accidental pileup
• It performs the simulation in 1.6 sec/event.
  100,000 accidental backups were generated.
• Procedure
• Distribute RD events and Michel positrons
  randomly according to specified event rate in
  2.5 micro sec.
• If total energy deposit in the calorimeter is
  smaller than a threshold, it repeats the first
  step until total energy deposit becomes larger
  than the threshold.
• Search the most energetic gamma ray. From time of
  the gamma ray, it searches a positron whose
  kinematics meets the trigger condition.
• Rotate all Michel decay sub-events in 2.5 micro
  sec time region so that the selected Michel
  positron comes around the most energetic gamma
  ray. The time differences between the gamma and
  the Michel positron are distributed randomly
  within specified time window.

2
Bartender - prompt background in signal region

• Around 5000 prompt background events were
  generated.
• RD with a high energy gamma and a high energy
  positron Michel pileups RD pileups.
• 1.2 sec/events for bartender.
• In this production, trigger efficiency was too
  low. I will investigate the reason.
• gem, X gt 0.9, Y gt 0.25, RD, 10000 events
• Less than 500 events were triggered in bartender.
• Maybe opening angle did not meet the pre-trigger
  condition. (gt 173 degree) If it is the case, we
  may need to make a new key for gem to specify
  opening angle.

3
Nsum3(total charge corrected with total PMT
coverage)
C Normalization factor ( constant ) O Total
PMT coverage viewed from reconstructed position N
Number of photons observed by a PMT
We could also take into account attenuation and
scattering. Detailed study of the result is not
done yet. If we increase corrections, several
parameters can affect the energy resolution (
position reconstruction, attenuation length
estimation, simulation settings...). It is not
clear how much we should do correction.
Philosophy of this calorimeter is measuring
energy without complicated correction.
Nsum
Nsum2
Nsum3