Work

Relative difference between up and down quark structure of the proton

Year: 2025

Type: preprint

Abstract: We presen a novel determination of the down-to-up composition ratio using the forward-backward asymmetry observed in the proton-proton collisions at the LHC. This method offers unique insights into the flavor-specific difference between down and up quarks, which are difficult to isolate in traditional cross-section measurements due to the inherent mixing of contributions from both flavors. In this study, we systematically measure the down-to-up quark ratio over a broad momentum fraction (x) range of 0.01 to 0.1, utilizing the sensitivity of the forward-backward asymmetry to quark-level couplings. Our findings reveal significant deviations in both the value and x-dependence of this ratio compared to predictions from current parton distribution functions (PDFs). These discrepancies highlight potential limitations in existing PDF parameterization and emphasize the importance of flavor-separated measurements for advancing our understanding of proton structure.

Source: arXiv (Cornell University)

Authors: Xie, Mingzhe, Yang, Siqi, Ma, Wenhao, Liu, Minghui, Han, Liang, Yuan, C. -P.

Institutions: University of Science and Technology of China, Michigan State University

Language: English

Topic: Quantum Chromodynamics and Particle Interactions

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, National Natural Science Foundation of China

Awards: G2119575847, G4027603011, G4617888044, G7227638078, G7839043245, Global QCD Analysis and Precision Electroweak Physics in High Energy Collier Phenomenology

OpenAlex ID: W6979367455

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