Non-global logarithms and fiducial transverse-momentum-dependent observables in deep-inelastic scattering
Abstract
Extracting the intrinsic transverse-momentum structure of quarks from deep-inelastic scattering data requires separating nonperturbative effects from perturbative radiation, which broadens the measured transverse-momentum distributions. We address this problem in electron--proton scattering, ep→ eX, by introducing the fiducial imbalance qT, defined as the vector sum of the scattered electron's transverse momentum and all hadronic transverse momenta within a specified rapidity window. This construction reduces radiative recoil without requiring jet reconstruction or an explicit jet veto. We account for non-global logarithms (NGLs) arising from correlated soft emissions across the acceptance boundary. The azimuthally averaged NGL contribution is resummed to all orders at leading-logarithmic accuracy in the large-Nc limit using Banfi--Marchesini--Smye evolution, while the leading NGL correction to the first azimuthal harmonic is included at 𝒪(αs2). For the EIC and EicC kinematics considered, widening the rapidity window increases the cross section at low qT, a region particularly sensitive to nonperturbative transverse dynamics, and reduces the dilution of spin asymmetries by azimuthally symmetric soft recoil. Both the Sivers single-spin asymmetry AUT and the worm-gear double-spin asymmetry ALT increase in magnitude, while the qT integrated cross section remains unchanged. The unpolarized cosϕ moment generated by soft gluon radiation is sensitive to NGL effects, with its ratio definition reducing common normalization uncertainties. The absence of jet reconstruction makes this observable particularly relevant at the lower collision energies of EicC, providing a way to study nonperturbative spin--momentum correlations by varying the fiducial acceptance.
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BibTeX
@misc{lin2026nonglobal,
title = {{Non-global logarithms and fiducial transverse-momentum-dependent observables in deep-inelastic scattering}},
author = {Shuo Lin and Jian Zhou},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.36523},
eprint = {2609.36523},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.36523},
}
RIS
TY - UNPB
TI - Non-global logarithms and fiducial transverse-momentum-dependent observables in deep-inelastic scattering
AU - Shuo Lin
AU - Jian Zhou
PY - 2026
DA - 2026/09/29
PB - arXiv
DO - 10.48550/arxiv.2609.36523
UR - https://arxiv.org/abs/2609.36523
AB - Extracting the intrinsic transverse-momentum structure of quarks from deep-inelastic scattering data requires separating nonperturbative effects from perturbative radiation, which broadens the measured transverse-momentum distributions. We address this problem in electron--proton scattering, ep→ eX, by introducing the fiducial imbalance q_T, defined as the vector sum of the scattered electron's transverse momentum and all hadronic transverse momenta within a specified rapidity window. This construction reduces radiative recoil without requiring jet reconstruction or an explicit jet veto. We account for non-global logarithms (NGLs) arising from correlated soft emissions across the acceptance boundary. The azimuthally averaged NGL contribution is resummed to all orders at leading-logarithmic accuracy in the large-N_c limit using Banfi--Marchesini--Smye evolution, while the leading NGL correction to the first azimuthal harmonic is included at 𝒪(α_s^2). For the EIC and EicC kinematics considered, widening the rapidity window increases the cross section at low q_T, a region particularly sensitive to nonperturbative transverse dynamics, and reduces the dilution of spin asymmetries by azimuthally symmetric soft recoil. Both the Sivers single-spin asymmetry A_UT and the worm-gear double-spin asymmetry A_LT increase in magnitude, while the q_T integrated cross section remains unchanged. The unpolarized cosϕ moment generated by soft gluon radiation is sensitive to NGL effects, with its ratio definition reducing common normalization uncertainties. The absence of jet reconstruction makes this observable particularly relevant at the lower collision energies of EicC, providing a way to study nonperturbative spin--momentum correlations by varying the fiducial acceptance.
ER -