Work

Exploring the Three-Dimensional Momentum Distribution of Longitudinally Polarized Quarks in the Proton

Year: 2025

Type: article

Abstract: By analyzing experimental data on semi-inclusive deep inelastic scattering off longitudinally polarized targets, we extract the transverse momentum dependence of the quark helicity distribution, i.e., the difference between the three-dimensional motion of quarks with polarization parallel or antiparallel to the longitudinal polarization of the parent hadron. We perform the analysis at next-to-leading and next-to-next-to-leading perturbative accuracy. The quality of the fit is very good for both cases, reaching a χ^{2} per number of data points equal to 1.11 and 1.09, respectively. Although the limited number of data points leads to significant uncertainties, the data are consistent with an interpretation in which the helicity distribution is narrower in transverse momentum than the unpolarized distribution.

Source: Physical Review Letters

DOI: 10.1103/physrevlett.134.121901

Authors: Alessandro Bacchetta, Alessia Bongallino, Matteo Cerutti, Marco Radici, Lorenzo Rossi

Institutions: University of Pavia, Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, University of the Basque Country, Christopher Newport University, Thomas Jefferson National Accelerator Facility

Language: English

Topic: Quantum Chromodynamics and Particle Interactions

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,750