Physics and Astronomy
Journal or Book Title
Physical Review C
We present a new analysis of J/psi production yields in deuteron-gold collisions at root s(NN) =200 GeV using data taken from the PHENIX experiment in 2003 and previously published in S. S. Adler [Phys. Rev. Lett 96, 012304 (2006)]. The high statistics proton-proton J/psi data taken in 2005 are used to improve the baseline measurement and thus construct updated cold nuclear matter modification factors (R-dAu). A suppression of J/psi in cold nuclear matter is observed as one goes forward in rapidity (in the deuteron-going direction), corresponding to a region more sensitive to initial-state low-x gluons in the gold nucleus. The measured nuclear modification factors are compared to theoretical calculations of nuclear shadowing to which a J/psi (or precursor) breakup cross section is added. Breakup cross sections of sigma(breakup)=2.8(-1.4)(+1.7) (2.2(-1.5)(+1.6)) mb are obtained by fitting these calculations to the data using two different models of nuclear shadowing. These breakup cross-section values are consistent within large uncertainties with the 4.2 +/- 0.5 mb determined at lower collision energies. Projecting this range of cold nuclear matter effects to copper-copper and gold-gold collisions reveals that the current constraints are not sufficient to firmly quantify the additional hot nuclear matter effect.
American Physical Society
Adare, Andrew; Constantin, Paul; Grau, Nathan C.; Hill, John C.; Lajoie, John G.; Lebedev, Alexandre; Ogilvie, Craig; Pei, H.; Rak, Jan; Rosati, Marzia; Skutnik, S.; Vale, Carla; Wohn, F. K.; Zong, X.; et al.; and PHENIX Collaboration, "Cold nuclear matter effects on J/psi production as constrained by deuteron-gold measurements at root S-NN=200 GeV" (2008). Physics and Astronomy Publications. 339.