Polarized dipole scattering amplitudes meet the valence quark model

Journal Article · 20 September 2024 · Physical Review. D.

DOI: https://doi.org/10.1103/PhysRevD.110.054030 · OSTI ID:2447537

Dumitru, Adrian ; Mäntysaari, Heikki ; Tawabutr, Yossathorn

The recently revised small- $x$ helicity evolution [], resumming the double-logarithmic factor, ${\alpha }_{\mathrm{s}}{\ln }^2(1/x)$ , 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, ${\alpha }_{\mathrm{s}}{\ln }^2(1/x)\sim 1$ , 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. Published by the American Physical Society 2024

• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• Grant/Contract Number: SC0002307
• OSTI ID: 2447537
• Journal Information: Physical Review. D., Journal Name: Physical Review. D. Journal Issue: 5 Vol. 110; ISSN PRVDAQ; ISSN 2470-0010
• Publisher: American Physical SocietyCopyright Statement
• Country of Publication: United States
• Language: English