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arXiv · 2108.05822

Global QCD Analysis of Pion Parton Distributions with Threshold Resummation

P. C. Barry·Chueng-Ryong Ji·N. Sato·W. Melnitchouk
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Abstract

We perform the first global QCD analysis of pion valence, sea quark, and gluon distributions within a Bayesian Monte Carlo framework with threshold resummation on Drell-Yan cross sections at next-to-leading log accuracy. Exploring various treatments of resummation, we find that the large-$x$ asymptotics of the valence quark distribution $\sim (1-x)^{β_v}$ can differ significantly, with $β_v$ ranging from $\approx 1$ to $> 2.5$ at the input scale. Regardless of the specific implementation, however, the resummation induced redistribution of the momentum between valence quarks and gluons boosts the total momentum carried by gluons to $\approx 40\%$, increasing the gluon contribution to the pion mass to $\approx 40$ MeV.

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P. C. Barry, Chueng-Ryong Ji, N. Sato, W. Melnitchouk. 2021-11-30. Global QCD Analysis of Pion Parton Distributions with Threshold Resummation. https://doi.org/10.1103/physrevlett.127.232001

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