Inclusive Charged Pion Cross Section - First Look

Correction factors are derived from simulation by taking the ratio of the reconstructed primary tracks matched to MC pions divided by the MC pions. Specifically, the following cuts are applied:

Monte Carlo
  • |event_vz| < 60.
  • |eta| < 1.
  • nhits > 25
  • geantID == 8||9 (charged pions)

Matched Reco Tracks
  • |event_vz|<60.
  • |reco eta| < 1.
  • |global DCA| < 1.
  • reco fit points > 25
  • geantID of matched track == 8||9
The track yields and their associated yields are obtained from the minimc files that are produced automatically with each simulation request. I run a separate chain containing StEmcTriggerMaker on the MuDst simulation files to determine if each event would have satisfied EMC and BBC trigger conditions.

There is currently a bug in StDetectorDbMaker that makes it difficult to retrieve accurate prescales using only a catalog query for the filelist. This affects the absolute scale of each cross section and data points for HT1 and JP1 relative to the other three triggers. It's probably a 10%-20% effect for HT1 and JP1. With that in mind, here's what I have so far:

This plot is generated from a fraction of the full dataset; I stopped my jobs when I discovered the prescales bug.

The cuts used to select good events from the data are:
  • golden run list, version c
  • |vz| < 60.
  • Right now I am only using the first vertex from each event, but it's easy for me to change

The cuts used to select pion tracks are the same as the ones used for "Matched Reco Tracks", except for the PID cut of course. For PID I require that the dE/dx value of the track is between -1 and 2 sigma away from the mean for pions.

As always, comments are welcome.