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arXiv · 2407.08893

Polarized Dipole Scattering Amplitudes meet the Valence Quark Model

Adrian Dumitru·Heikki Mäntysaari·Yossathorn Tawabutr
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Abstract

The recently revised small-$x$ helicity evolution, resumming the double-logarithmic factor, $α_s\ln^2(1/x)$, allows for the study of helicity distributions of quarks and gluons at small Bjorken $x$, corresponding to high center-of-mass energy. In this work, we calculate the moderate-$x$ initial conditions in the regime, $α_s \ln^2(1/x)\sim 1$, for the small-$x$ helicity evolution using a light-front valence quark model of the proton, which provides additional physical information about the target. The perturbative emission and absorption of a gluon by the valence quarks are also included. The results, given in Eqs. (35), provide a new set of initial conditions with a significantly reduced number of free parameters than conventional models. Consequently, the predictive power of small-$x$ helicity evolution is expected to improve once the initial conditions from this work are incorporated.

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Adrian Dumitru, Heikki Mäntysaari, Yossathorn Tawabutr. 2024-07-11. Polarized Dipole Scattering Amplitudes meet the Valence Quark Model. https://arxiv.org/abs/2407.08893

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