Azimuthal angular correlation of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>J</mml:mi><mml:mo>/</mml:mo><mml:mi>ψ</mml:mi></mml:math> plus jet production at the electron-ion collider

By investigating the soft gluon radiation in the <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> plus jet photoproduction at the electron-ion collider (EIC), we demonstrate that the azimuthal angular correlations between the leading jet and heavy quarkonium provide a unique probe to the production mechanism of the latter. In particular, a significant <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>cos</c:mi><c:mo stretchy="false">(</c:mo><c:mi>ϕ</c:mi><c:mo stretchy="false">)</c:mo></c:math> asymmetry is found for the color-singlet channel, whereas it vanishes or has an opposite sign for color-octet production, depending on the jet transverse momentum. Numerical results of <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mi>cos</g:mi><g:mo stretchy="false">(</g:mo><g:mi>ϕ</g:mi><g:mo stretchy="false">)</g:mo></g:math> and <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mi>cos</k:mi><k:mo stretchy="false">(</k:mo><k:mn>2</k:mn><k:mi>ϕ</k:mi><k:mo stretchy="false">)</k:mo></k:math> asymmetries employing both the color-singlet model and the nonrelativistic QCD approach are presented for typical kinematics at the future EIC. Published by the American Physical Society 2024