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arXiv · 0811.3662

Low-mass lepton pair production at large transverse momentum

Zhong-Bo Kang·Jian-Wei Qiu·Werner Vogelsang
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Abstract

We study the transverse momentum distribution of low-mass lepton pairs produced in hadronic scattering, using the perturbative QCD factorization approach. We argue that the distribution at large transverse momentum, $Q_T \gg Q$, with the pair's invariant mass $Q$ as low as $Q \sim Λ_{\mathrm{QCD}}$, can be systematically factorized into universal parton-to-lepton pair fragmentation functions, parton distributions, and perturbatively calculable partonic hard parts evaluated at a short distance scale $\sim {\cal O}(1/Q_T)$. We introduce a model for the input lepton pair fragmentation functions at a scale $μ_0\sim 1$ GeV, which are then evolved perturbatively to scales relevant at RHIC. Using the evolved fragmentation functions, we calculate the transverse momentum distributions in hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions at RHIC. We also discuss the sensitivity of the transverse momentum distribution of low-mass lepton pairs to the gluon distribution.

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Zhong-Bo Kang, Jian-Wei Qiu, Werner Vogelsang. 2009-02-20. Low-mass lepton pair production at large transverse momentum. https://doi.org/10.1103/physrevd.79.054007

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