Measurements of Unpolarized Azimuthal Asymmetries at COMPASS
W. Käfer
TL;DR
This paper reports the first measurement of azimuthal asymmetries in the unpolarized SIDIS cross section using muon beams on a deuteron target at COMPASS. The study targets the transverse momentum structure of quarks inside the nucleon and aims to access the Boer-Mulders function through azimuthal-angle modulations, alongside the Cahn effect as a competing mechanism. The authors discuss the theoretical motivation and outline the measurement approach for extracting azimuthal asymmetries from SIDIS data. The results provide experimental input to constrain transverse momentum-dependent parton distributions and Boer-Mulders models, with implications for our understanding of nucleon structure and TMD phenomenology.
Abstract
Azimuthal Asymmetries in unpolarized SIDIS can be used to probe the transverse momentum of quarks inside the nucleon. Furthermore, they give access to the so-far unmeasured Boer-Mulders function. We report on the first measurement of azimuthal asymmetries of the SIDIS cross section from scattering of muons off a deuteron target.