Initial results from the HARP experiment at CERN

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.