sPHENIX discussion of software

[Kurt Keys Hill <Kurt.Hill AT colorado.edu>]

Hi All,

The Colorado group is interested in particle flow jet reconstruction in sPHENIX. As a first step, we would like to separate electromagnetic from hadronic EMCal clusters within the jet and apply the appropriate energy scale to each type. We plan to eventually apply a track-cluster replacement scheme as a next step.

Moving toward EMCal cluster identification, I have merged Sasha's pull request into a local copy of g4cemc. I ran single pions and electrons through an otherwise default sPHENIX and plotted the chi2 and prob distributions in four different EMC cluster energy selections (see attached slides). In the lowest energy (0-1 GeV) the charged pion deposits MI energy which seem to look a lot like low energy EM showers. At higher energy, there seems to be fairly good separation between the EM and hadronic showers, and at the highest energies the pi0 curve separates from the electrons - presumably as the two photon showers merge.

Even at substantial energy, the purely electromagnetic showers from the single electrons have a significant chance to produce a prob value of near 0. Is this expected? 

As an aside, I would like to understand the current applied calorimeter calibrations better. I am using the calibrated calorimeter towers and clusters; I assume the default energy scale given to the EMC is calibrated to electromagnetic showers. If so, is the EMC hadronic energy scale known, or should I calculate it? Any advice here would be appreciated.

I plan to call into the simulations meeting tomorrow, so we could chat about it then if there is time.

Thanks,

Kurt

Attachment: sPhenixParticleFlow_06112017.pdf
Description: Adobe PDF document