# Cold Nuclear Matter Effects on $J/\Psi$ production as Constrained by Deuteron-Gold Measurements at $\sqrt{s_{NN}}$ = 200 GeV

Abstract : We present a new analysis of J/psi production yields in deuteron-gold collisions at sqrt(s_NN) = 200 GeV using data taken by the PHENIX experiment in 2003 and previously published in [S.S. Adler et al., Phys. Rev. Lett 96, 012304 (2006)]. The high statistics proton-proton J/psi data taken in 2005 is 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) break-up cross-section is added. Breakup cross sections of sigma_breakup = 2.8^[+1.7_-1.4] (2.2^[+1.6_-1.5]) 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.
Document type :
Journal articles

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Submitted on : Monday, December 3, 2007 - 11:32:10 AM
Last modification on : Saturday, October 9, 2021 - 3:59:57 AM

### Citation

A. Adare, S.S. Adler, S. Afanasiev, C. Aidala, N.N. Ajitanand, et al.. Cold Nuclear Matter Effects on $J/\Psi$ production as Constrained by Deuteron-Gold Measurements at $\sqrt{s_{NN}}$ = 200 GeV. Physical Review C, American Physical Society, 2008, 77, pp.024912. ⟨10.1103/PhysRevC.77.024912⟩. ⟨in2p3-00193294⟩

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