Polarized J/ψ production in semi-inclusive DIS at large Q2 : Comparing quark fragmentation and photon-gluon fusion

We compare the relative importance of different mechanisms for polarized <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>J</a:mi><a:mo>/</a:mo><a:mi>ψ</a:mi></a:math> production in semi-inclusive deep inelastic scattering processes at large <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:msup><c:mi>Q</c:mi><c:mn>2</c:mn></c:msup></c:math>. The transverse momentum dependent (TMD) factorization framework and nonrelativistic quantum chromodynamics are used to study the leading contributions from light quark fragmentation to polarized <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>J</e:mi><e:mo>/</e:mo><e:mi>ψ</e:mi></e:math>, and compared to direct production via photon-gluon fusion, which can proceed through color-singlet as well as color-octet mechanisms. We identify kinematic regimes where light quark fragmentation dominates, allowing for the extraction of the <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mrow><g:msubsup><g:mrow><g:mmultiscripts><g:mrow><g:mi>S</g:mi></g:mrow><g:mprescripts/><g:none/><g:mrow><g:mn>3</g:mn></g:mrow></g:mmultiscripts></g:mrow><g:mrow><g:mn>1</g:mn></g:mrow><g:mrow><g:mo stretchy="false">[</g:mo><g:mn>8</g:mn><g:mo stretchy="false">]</g:mo></g:mrow></g:msubsup></g:mrow></g:math> matrix element, as well as regimes where photon gluon fusion dominates, suggesting that the gluon TMD parton distribution function can be probed. Published by the American Physical Society 2024