Nonperturbative Collins-Soper kernel from chiral quarks with physical masses

Mar 1, 2024
7 pages
Published in:
  • Phys.Lett.B 852 (2024) 138617
  • Published: Apr 2, 2024
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Abstract: (Elsevier B.V.)
We present a lattice QCD calculation of the rapidity anomalous dimension of quark transverse-momentum-dependent distributions, i.e., the Collins-Soper (CS) kernel, up to transverse separations of about 1 fm. This unitary lattice calculation is conducted, for the first time, employing the chiral-symmetry-preserving domain wall fermion discretization and physical values of light and strange quark masses. The CS kernel is extracted from the ratios of pion quasi-transverse-momentum-dependent wave functions (quasi-TMDWFs) at next-to-leading logarithmic perturbative accuracy. Also for the first time, we utilize the recently proposed Coulomb-gauge-fixed quasi-TMDWF correlator without a Wilson line. We observe significantly slower signal decay with increasing quark separations compared to the established gauge-invariant method with a staple-shaped Wilson line. This enables us to determine the CS kernel at large nonperturbative transverse separations and find its near-linear dependence on the latter. Our result is consistent with the recent lattice calculation using gauge-invariant quasi-TMDWFs, and agrees with various recent phenomenological parametrizations of experimental data.
Note:
  • 7 pages, 4 figures; published version
  • Transverse-momentum-dependent distributions
  • Collins-Soper kernel
  • Lattice QCD
  • Coulomb gauge
  • Domain-wall fermion
  • invariance: gauge
  • quark: chiral
  • fermion: domain wall
  • quark: mass
  • Wilson loop