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arXiv · 1305.1724

Evidence for nuclear gluon shadowing from the ALICE measurements of PbPb ultraperipheral exclusive J/ψ production

V. Guzey·E. Kryshen·M. Strikman·M. Zhalov
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Abstract

We show that the recent ALICE measurements of exclusive J/ψ production in ultraperipheral PbPb collisions at 2.76 TeV provide the first direct experimental evidence for the strong nuclear gluon shadowing in lead at $x \sim 10^{-3}$. The evidence is based on the comparison of the nuclear suppression factor S(x\approx 0.001)=0.61^{+0.05}_{-0.04} found in the analysis of the coherent J/ψ photoproduction cross sections measured by ALICE with the nuclear gluon shadowing predicted by the global fits of nuclear parton distributions and by the leading twist theory of nuclear shadowing.

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V. Guzey, E. Kryshen, M. Strikman, M. Zhalov. 2013-10-09. Evidence for nuclear gluon shadowing from the ALICE measurements of PbPb ultraperipheral exclusive J/ψ production. https://doi.org/10.1016/j.physletb.2013.08.043

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