Measurements of cross sections and charged pion spectra in proton-carbon interactions at 31 GeV/<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>c</mml:mi></mml:math>

Abstract

Interaction cross sections and charged pion spectra in $p+\mathrm{C}$ interactions at 31 GeV/$c$ were measured with the large-acceptance NA61/SHINE spectrometer at the CERN SPS. These data are required to improve predictions of the neutrino flux for the T2K long-baseline neutrino oscillation experiment in Japan. A set of data collected during the first NA61/SHINE run in 2007 with an isotropic graphite target with a thickness of 4% of a nuclear interaction length was used for the analysis. The measured $p+\mathrm{C}$ inelastic and production cross sections are 257.2 $\ifmmode\pm\else\textpm\fi{}$ 1.9 $\ifmmode\pm\else\textpm\fi{}$ 8.9 and 229.3 $\ifmmode\pm\else\textpm\fi{}$ 1.9 $\ifmmode\pm\else\textpm\fi{}$ 9.0 mb, respectively. Inclusive production cross sections for negatively and positively charged pions are presented as functions of laboratory momentum in ten intervals of the laboratory polar angle covering the range from 0 up to 420 mrad. The spectra are compared with predictions of several hadron production models.