Measurement of the proton-air inelastic cross section at √(s)≅2 TeV from the EAS-TOP experiment

The proton-air inelastic cross section (σp-airinel) is measured at √(s)≅2 TeV at the EAS-TOP extensive air shower experiment by studying the absorption length of cosmic ray proton primaries cascades reaching the maximum development at the observation level. Primary energies, in the region E0=(1.5 divide 2.5)·1015 eV, are selected through the EAS muon number (Nμ), and proton originated cascades at maximum development are selected by means of the shower size (Ne). The observed absorption length (λobs) is a convolution of the proton-air interaction length (λp-air) and of the shower and detector fluctuations. The conversion factor k=λobs/λint is obtained by means of simulations performed with the CORSIKA code and the QGSJET II and SIBYLL interaction models. The obtained value of the p-air inelastic cross section at √(s)≅2 TeV is σp-airinel=338±21(stat)±19(syst)-28(syst) mb. The statistical and systematic uncertainties, as well as the relationships with the pp (pp) total cross section measurements are discussed.