TMD observables in unpolarised Semi-Inclusive DIS at COMPASS

TL;DR

This paper presents preliminary results from the COMPASS experiment on azimuthal modulations and transverse-momentum distributions of charged hadrons in unpolarized semi-inclusive deep inelastic scattering, shedding light on nucleon structure.

Contribution

It provides new measurements of TMD observables in unpolarized SIDIS at COMPASS, including azimuthal asymmetries and transverse-momentum distributions, with detailed kinematic dependences.

Findings

Azimuthal asymmetries show interesting kinematic dependences.

Transverse-momentum distributions are well described by two exponentials.

Preliminary results contribute to understanding nucleon transverse momentum and spin structure.

Abstract

In 2016 and 2017, the COMPASS Collaboration at CERN collected a large sample of DIS events with a longitudinally polarized 160 GeV/c muon beam scattering off a liquid hydrogen target. Part of the collected data has been analyzed to extract preliminary results for the amplitudes of the modulations in the azimuthal angle of the charged hadrons and for their transverse-momentum distributions. These observables give relevant information for the study of the transverse momentum and spin structure of the nucleon. Similarly to the results obtained in COMPASS with a deuteron target, the azimuthal asymmetries exhibit interesting kinematic dependences, while the squared-transverse-momentum distributions can be described by two exponentials.