2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/37720The first physics results of the HARP experiment are presented. We emphasize the high performance of the forward part of the apparatus. The differential raw pion yield and its efficiency correction up to polar angles of 250 mrad are shown. The analysed setting is 12.9 GeV/c incident protons in a 5% interacion legth aluminium target.6 pages, 10 figures. Proceedings of the conference Rencontres de Moriond 2004High Energy Physics - Experimenttext