Measurement of negatively charged pion spectra in inelastic p+p interactions at $$p_{\mathbf {lab}}= $$ p lab = 20, 31, 40, 80 and 158 GeV/c

We present experimental results on inclusive spectra and mean multiplicities of negatively charged pions produced in inelastic p+p interactions at incident projectile momenta of 20, 31, 40, 80 and 158 GeV/c (√s = 6.3, 7.7, 8.8, 12.3 and 17.3 GeV, respectively). The measurements were performed using the large acceptance NA61/SHINE hadron spectrometer at the CERN Super Proton Synchro- tron. Two-dimensional spectra are determined in terms of ra- pidity and transverse momentum. Their properties such as the width of rapidity distributions and the inverse slope pa- rameter of transverse mass spectra are extracted and their collision energy dependences are presented. The results on inelastic p+p interactions are compared with the correspond- ing data on central Pb+Pb collisions measured by the NA49 experiment at the CERN SPS. The results presented in this paper are part of the NA61/ SHINE ion program devoted to the study of the properties of the onset of deconfinement and search for the critical point of strongly interacting matter. They are required for inter- pretation of results on nucleus-nucleus and proton-nucleus collisions.