TY - JOUR

T1 - Quark orbital angular momentum in the proton from a twist-3 generalized parton distribution

AU - Engelhardt, M.

AU - Hasan, N.

AU - Krieg, S.

AU - Liuti, S.

AU - Meinel, S.

AU - Negele, J.

AU - Pochinsky, A.

AU - Rodekamp, M.

AU - Syritsyn, S.

N1 - Publisher Copyright:
© Copyright owned by the author(s) under the terms of the Creative Commons.

PY - 2024/7/30

Y1 - 2024/7/30

N2 - Quark orbital angular momentum in the proton is evaluated via a Lattice QCD calculation of the second Mellin moment of the twist-3 generalized parton distribution Ee2T in the forward limit. The connection between this approach to quark orbital angular momentum and approaches previously utilized in Lattice QCD calculations, via generalized transverse momentum-dependent parton distributions and via Ji’s sum rule, is reviewed. This connection can be given in terms of Lorentz invariance and equation of motion relations. The calculation of the second Mellin moment of Ee2T proceeds via a finite-momentum proton matrix element of a quark bilocal operator with a straight-line gauge connection and separation in both the longitudinal and transverse directions. The dependence on the former component serves to extract the second Mellin moment, whereas the dependence on the latter component provides a transverse momentum cutoff for the matrix element. Furthermore, a derivative of the matrix element with respect to momentum transfer in the forward limit is required, which is obtained using a direct derivative method. The calculation utilizes a clover fermion ensemble at pion mass 317 MeV. The resulting quark orbital angular momentum is consistent with previous evaluations through alternative approaches, albeit with greater statistical uncertainty using a comparable number of samples.

AB - Quark orbital angular momentum in the proton is evaluated via a Lattice QCD calculation of the second Mellin moment of the twist-3 generalized parton distribution Ee2T in the forward limit. The connection between this approach to quark orbital angular momentum and approaches previously utilized in Lattice QCD calculations, via generalized transverse momentum-dependent parton distributions and via Ji’s sum rule, is reviewed. This connection can be given in terms of Lorentz invariance and equation of motion relations. The calculation of the second Mellin moment of Ee2T proceeds via a finite-momentum proton matrix element of a quark bilocal operator with a straight-line gauge connection and separation in both the longitudinal and transverse directions. The dependence on the former component serves to extract the second Mellin moment, whereas the dependence on the latter component provides a transverse momentum cutoff for the matrix element. Furthermore, a derivative of the matrix element with respect to momentum transfer in the forward limit is required, which is obtained using a direct derivative method. The calculation utilizes a clover fermion ensemble at pion mass 317 MeV. The resulting quark orbital angular momentum is consistent with previous evaluations through alternative approaches, albeit with greater statistical uncertainty using a comparable number of samples.

UR - http://www.scopus.com/inward/record.url?scp=85200435046&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85200435046&partnerID=8YFLogxK

M3 - Conference article

AN - SCOPUS:85200435046

SN - 1824-8039

VL - 456

JO - Proceedings of Science

JF - Proceedings of Science

M1 - 075

T2 - 25th International Symposium on Spin Physics, SPIN 2023

Y2 - 24 September 2023 through 29 September 2023

ER -