Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: How To Find Charm in Nuclear Collisions at RHIC and LHC   Measurements of dilepton production from charm decay and Drell-Yan processes
respectively probe the gluon and sea quark distributions in hadronic
collisions. In nucleus-nucleus collisions, these hard scattering processes
constitute a `background' to thermal contributions from the hot matter produced
by the collision. To determine the magnitude and behavior of this background,
we calculate the hard scattering contribution to dilepton production in nuclear
collisions at RHIC and LHC at next to leading order in perturbative QCD.
Invariant mass, rapidity and transverse momentum distributions are presented.
We compare these results to optimistic hydrodynamic estimates of the thermal
dilepton production. We find that charm production from hard scattering is by
far the dominant contribution. Experiments therefore can measure the gluon
distribution in the nuclear target and projectile and, consequently, can
provide new information on gluon shadowing. We then illustrate how experimental
cuts on the rapidity gap between the leptons can aid in reducing the charm
background, thereby enhancing thermal information.

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The categories of this paper are: gr-qc
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The categories of this paper are: hep-lat
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The categories of this paper are: acc-phys
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The categories of this paper are: math
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The categories of this paper are: comp-gas
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The categories of this paper are: math-ph
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The categories of this paper are: adap-org
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The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: physics
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The categories of this paper are: hep-th
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The categories of this paper are: dg-ga
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The categories of this paper are: nlin
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-th