Asymmetries for near-side and away-side pions

I associated charged pions from JP2 events with the jets that were found in these events. If a jet satisfied a set of cuts (including the geometric cut to exclude non-trigger jets), I calculated a deltaR from this jet for each pion in my sample. Then I split up my sample into near-side and away-side pions and calculate an asymmetry for both samples.

Jet cuts:

  • R_T < 0.95
  • JP2 hardware, software, and geometric triggers satisfied

Note: all plots are pi- on the left and pi+ on the right

This first set of plots shows eta(pion)-eta(jet) on the x axis and phi(pion)-phi(jet) on the y axis. You can see the intense circle around (0,0) from pions inside the jet cone radius as well as the regions around the top and bottom of the plots from the away-side jet:

Next I calculate deltaR = sqrt(deta*deta + dphi*dphi) for both samples. Again you can see the sharp cutoff at deltaR=0.4 from the jetfinder:


My original asymmetries for JP2 without requiring a jet in the event:

After requiring a jet in the event I get

Now look at the asymmetry for near-side pions, defined by a cone of deltaR<0.4:

And similarly the asymmetries for away-side pions, defined by deltaR>1.5:

Conclusions: No showstoppers. The statistics for away-side pions are only about a factor of 2 worse than the stats for near-side (I can post the exact numbers later). The asymmetries are basically in agreement with each other, although the first bin for pi+ and the second bin for pi- do show 1 sigma differences between near-side and away-side.