Charged pion spectra in proton—carbon interactions at 31 GeV/c

The NA61/SHINE experiment at CERN SPS measured charged pion spectra in p+C interactions at 31 GeV/c. These measurements are necessary to improve predictions of the neutrino flux for the T2K long baseline neutrino oscillation experiment in Japan. Presented analysis was based on the data collected during the first NA61/SHINE run in 2007 with an isotropic graphite target with a thickness of 4% of nuclear interaction length. Three different methods which were used in order to obtain π+ and π− spectra are introduced. Differential cross sections for negatively and positively charged pions are presented as a function of laboratory momentum in ten intervals of the laboratory polar angle up to 420 mrad.