SMuK 2023 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

HK: Fachverband Physik der Hadronen und Kerne

HK 18: Hadron Structure and Spectroscopy II

HK 18.6: Vortrag

Dienstag, 21. März 2023, 18:30–18:45, SCH/A316

Numerical evaluation of the > nonlinear GLR-MQ equations for nuclear parton distribution functions — •Janik Rausch¹, Vadim Guzey² und Michael Klasen³ — ¹Humboldt-Universität Berlin, Deutschland — ²Universität Jyväskylä, Finnland — ³Westfälische Wilhelms-Universität Münster, Deutschland

We numerically study for the first time the nonlinear GLR-MQ evolution equations for nuclear parton distribution function (nPDFs) to NLO accuracy and quantify the impact of gluon recombination at small x. Using the nCTEQ15 nPDFs as input, we confirm the importance of the nonlinear corrections for small x 10⁻³, whose magnitude increases with a decrease of x and an increase of the atomic number A. We find that at x=10⁻⁵ and for heavy nuclei, after the upward evolution from Q₀=2 GeV to Q=10 GeV, the quark singlet Ω(x,Q²) and the gluon G(x,Q²) distributions become reduced by 9−15%, respectively. The relative effect is much stronger for the downward evolution from Q₀=10 GeV to Q=2 GeV, where we find that Ω(x,Q²) is suppressed by 40%, while G(x, Q²) is enhanced by 140%. These trends propagate into the F_2A(x,Q²) nuclear structure function and the F_L^A(x,Q²) longitudinal structure function, which after the downward evolution become reduced by 45% and enhanced by 80%, respectively. Our analysis indicates that the nonlinear effects are most pronounced in F_L^A(x,Q²) and are already quite sizable at x ∼ 10⁻³ for heavy nuclei.