Initial results from the HARP experiment at CERN

Abstract

Initial results on particle yields obtained by the HARP experiment are presented. The measurements correspond to proton--nucleus collisions at beam energies of 12.9 $GeV/c$ and for a thin Al target of 5% interacion legth. The angular range considered is between 10 and 250 $mrad$. This results are the first step in the upcoming measurement of the forward production cross-section for the same target and beam energy, relevant for the calculation of the far--to--near ratio of the K2K experiment.