Bonino Leonardo, Gehrmann Thomas, Löchner Markus, Schönwald Kay, Stagnitto Giovanni
Physik-Institut, <a href="https://ror.org/02crff812">Universität Zürich</a>, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
<a href="https://ror.org/01ynf4891">Università degli Studi di Milano-Bicocca</a> and INFN, Piazza della Scienza 3, 20216 Milano, Italy.
Phys Rev Lett. 2024 Nov 22;133(21):211904. doi: 10.1103/PhysRevLett.133.211904.
Semi-inclusive hadron production in longitudinally polarized deep-inelastic lepton-nucleon scattering is a powerful tool for resolving the quark flavor decomposition of the proton's spin structure. We present the full next-to-next-to-leading order QCD corrections to the coefficient functions of polarized semi-inclusive deep-inelastic scattering (SIDIS) in analytical form, enabling the use of SIDIS measurements in precision studies of the proton spin structure. The numerical impact of these corrections is illustrated by a comparison with data of polarized single-inclusive hadron spectra from the DESY HERMES and CERN COMPASS experiments.
