The first plot shows the mass spectrum for all positively charged particles. The second plot imposes a cut on the mass to select only the positive pions.
The following plot shows the mass spectrum of all negatively charged particles. I suspect that the tall spike is the electrons and the small bump is the negative pions. The second plot implements a mass cut to only include those particles with M2 > 0.01 GeV. Its obvious that some of the pions are cut out with the electrons, so I intend to explore other ways to make this cut.