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Bibliographic Details
Main Author: STAR Collaboration
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2305.10359
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author STAR Collaboration
author_facet STAR Collaboration
contents We report a new measurement of transverse single-spin asymmetries for dijet production in collisions of polarized protons at $\sqrt{s}$ = 200 \mathrm{GeV}$. Correlations between the proton spin and the transverse momenta of its partons, each perpendicular to the proton momentum direction, are probed at high $Q^2$ $\approx $160 $\mathrm{GeV}^2$. Evidence for nonzero Sivers effects is measured for the first time in dijets from proton-proton collisions, but only when the jets are sorted by their net charge, which enhances the otherwise canceling opposite-sign $u$- or $d$-quark contributions to separate data samples. The resulting asymmetries are compared to recent theoretical calculations. Separately, the associated Sivers observable $\kt$, the average parton transverse momentum, is extracted using a simple kinematics approach which further enables a determination of the individual partonic contributions to the observed asymmetries.
format Preprint
id arxiv_https___arxiv_org_abs_2305_10359
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Measurement of transverse single-spin asymmetries for dijet production in polarized proton-proton collisions at $\mathbf{\sqrt{s}}$ = 200 $\mathbf{\mathrm{GeV}}$
STAR Collaboration
High Energy Physics - Experiment
Nuclear Experiment
We report a new measurement of transverse single-spin asymmetries for dijet production in collisions of polarized protons at $\sqrt{s}$ = 200 \mathrm{GeV}$. Correlations between the proton spin and the transverse momenta of its partons, each perpendicular to the proton momentum direction, are probed at high $Q^2$ $\approx $160 $\mathrm{GeV}^2$. Evidence for nonzero Sivers effects is measured for the first time in dijets from proton-proton collisions, but only when the jets are sorted by their net charge, which enhances the otherwise canceling opposite-sign $u$- or $d$-quark contributions to separate data samples. The resulting asymmetries are compared to recent theoretical calculations. Separately, the associated Sivers observable $\kt$, the average parton transverse momentum, is extracted using a simple kinematics approach which further enables a determination of the individual partonic contributions to the observed asymmetries.
title Measurement of transverse single-spin asymmetries for dijet production in polarized proton-proton collisions at $\mathbf{\sqrt{s}}$ = 200 $\mathbf{\mathrm{GeV}}$
topic High Energy Physics - Experiment
Nuclear Experiment
url https://arxiv.org/abs/2305.10359