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DOE OSTI · 2998100

Collins-Soper kernel in the QCD instanton vacuum

Liu, Wei-Yang [Stony Brook Univ., NY (United States)] (ORCID:0000000309384832)·Zahed, Ismail [Stony Brook Univ., NY (United States)]·Zhao, Yong [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000226886415)
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Abstract

We outline a general framework for evaluating the nonperturbative soft functions in the quantum chromodynamics (QCD) instanton vacuum. In particular, from the soft function we derive the Collins-Soper (CS) kernel, which drives the rapidity evolution of the transverse-momentum-dependent parton distributions. The resulting CS kernel, when supplemented with the perturbative contribution, agrees well with recent lattice results and some phenomenological parametrizations. Moreover, our CS kernel depends logarithmically on the large quark transverse separation, providing a key constraint on its phenomenological parametrization. Finally, a lattice calculation can be directly compared to our generic results in Euclidean signature, thus providing a new approach for evalulating the soft function and extracting the CS kernel by analytical continuation.

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QCD phenomenologyhadronsinstantonslattice QCDlight quarksquantum chromodynamicsrenormalizationstrong interaction

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Liu, Wei-Yang [Stony Brook Univ., NY (United States)] (ORCID:0000000309384832), Zahed, Ismail [Stony Brook Univ., NY (United States)], Zhao, Yong [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000226886415). 2025-04-16. Collins-Soper kernel in the QCD instanton vacuum. https://doi.org/10.1103/physrevd.111.074022

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