Photon Reconstruction in b1pi events 04/25/2012

50,000 b1pi events. EM background on. svn rev 9031.

All plots use thrown vertex information to decouple photon analysis from tracking.

BCAL

mcsmear behavior is modified so that noise hits do not affect timing of non-dark hits. Normal time-smearing still-applied.

Thrown photons

This is the z at which the photon would reach the inner radius of the BCAL.

Reconstructed "photons"

The plot below comes from DNeutralParticleHypothesis. At this stage the only cut that has been applied is rejecting clusters geometrically matched to charged tracks (this matching code is somewhat arcane and probably should be examined more closely. True facts: it does allow more than one cluster match per track, it reduces the number of clusters from 253,000 to the 175,000 below).

The z in these plots is cluster z at the presumed cluster maximum, not the z at the inner radius, so not directly comparable to thrown photon plot above.

Removing the lower right bin to get a more reasonable scale:

Reconstructed showers

Generate, simulate, and reconstruct samples of single-particle events with same kinematic distribution. These plots are made from DBCALShowers, this means that matching to charged tracks has not yet been performed, but non-linear energy corrections are applied.