J/ψ production in proton–nucleus collisions at 158 and 400 GeV

• DOI: 10.1016/j.physletb.2011.11.042
• Publication Date: 2011-11-24T03:00:04Z
• Authors: R. Arnaldi; K. Banicz; J. Castor; B. Chaurand; W. Chen; C. Cicalò; A. Colla; P. Cortese; S. Damjanovic; A. David; A. de Falco; A. Devaux; L. Ducroux; H. Enʼyo; J. Fargeix; A. Ferretti; M. Floris; A. Förster; P. Force; N. Guettet; A. Guichard; H. Gulkanian; J.M. Heuser; M. Keil; Z. Li; C. Lourenço; J. Lozano; F. Manso; P. Martins; A. Masoni; A. Neves; H. Ohnishi; C. Oppedisano; P. Parracho; P. Pillot; T. Poghosyan; G. Puddu; E. Radermacher; P. Ramalhete; P. Rosinsky; E. Scomparin; J. Seixas; S. Serci; R. Shahoyan; P. Sonderegger; H.J. Specht; R. Tieulent; A. Uras; G. Usai; R. Veenhof; H.K. Wöhri
• Keywords: 0103 physical sciences; FOS: Physical sciences; [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]; Nuclear Experiment (nucl-ex); 530; Nuclear Experiment; 01 natural sciences

NA60 Collaboration, accepted for publication by Phys. Lett. B<br/>The NA60 experiment has studied J/psi production in p-A collisions at 158 and 400 GeV, at the CERN SPS. Nuclear effects on the J/psi yield have been estimated from the A-dependence of the production cross section ratios sigma_{J/psi}^{A}/sigma_{J/psi}^{Be} (A=Al, Cu, In, W, Pb, U). We observe a significant nuclear suppression of the J/psi yield per nucleon-nucleon collision, with a larger effect at lower incident energy, and we compare this result with previous observations by other fixed-target experiments. An attempt to disentangle the different contributions to the observed suppression has been carried out by studying the dependence of nuclear effects on x_2, the fraction of nucleon momentum carried by the interacting parton in the target nucleus.<br/>