Note the pion analysis is done using Weihong He's pion finder (full explanation of this code is included in his thesis found here: STAR/files/userfiles/2992/Weihong Thesis.pdf).

Recently, the fitting function used to extract raw yields of the pions was modified (the new terms being the eta meson peak and the curvature term in the exponential background function as well as allowing the asymmetry parameter k to vary):

It was observed to be a stable fit and used in later analyses.

The centroid of the pions and etas were compared between run 9 and run 6 which showed that there had been a drop in gains of 7-8% (seen here: http://drupal.star.bnl.gov/STAR/blog/ncolmena/2011/mar/28/differences-etapion-centroids-run-6-and-9)

Using the W endcap trigger in run 11, the centroid for the pion peak was studied in three different PT bins to determine if the gains are getting worse. http://drupal.star.bnl.gov/STAR/blog/ncolmena/2011/may/10/quick-pt-bin-look-run-11

Due to the use of W triggers and their preference for high-pT events, it is not certain whether the gains are becoming worse or not.

Present: Run 9 pion cross-section/longitudinal asymmetry measurement.