NEW pi0 Mass vs. photon distance

Here are updated plots of the digamma invarient mass vs. distance between the photons.

In further studying the cause of the lower mass distribution in this previous blog, it was determined to be due to mishandling events where the vertex was not defined.  Specifically, "undefined" vertices are set to the warning value of (-999,-999,-999) cm, and previously this value was used as if it was the valid vertex, causing the mass to reconstruct low.  Now, a nominal vertex of the origin is used in the case of an undefined vertex.

The last blog used only cuts on digamma pT > 4 GeV and both photon energes > 3 GeV.  The first plots will be shown using the same cuts.  Afterwards, plots with a cut of photon energy > 1.5 are listed, to coincide with the newer cuts being considered.


IU Algorithm, photon E > 3 GeV


TSP Algorithm, photon E > 3 GeV


IU Algorithm, photon E > 1.5 GeV


TSP Algorithm, photon E > 1.5 GeV


Comment

Note: the proposed cut of Dgg < 25 cm only affects the Mgg distribution at Mgg > 0.2 GeV, outside the mass peak.