Reconstruction, March 2, 2010 Physics
From GlueXWiki
The resonance is generated flat in mass from 0.7 to 2.2 GeV/c^2 decays to ηπ0 to 4 gamma. The green line is the thrown events, the black is all reconstructable events where one charged particle is found and at least 4 photons. The red line is the same but with a cut on probability greater than 1%.
A plot of the kinematic fit probability versus the resonance mass. If all things were perfect, you would expect it to be a flat distribution, but there are features with a low number of events with higher probability at low mass and a spike of high probability near 2 GeV/c^2.
Linear scale:
same plot but logarithmic scale: