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Title: TMD factorization and evolution at large $$b_T$$

In using transverse-momentum-dependent (TMD) parton densities and fragmentation functions, important non-perturbative information is at large transverse position $$b_T$$. This concerns both the TMD functions and their evolution. Fits to high energy data tend to predict too rapid evolution when extrapolated to low energies where larger values of $$b_T$$ dominate. I summarize a new analysis of the issues. It results in a proposal for much weaker $$b_T$$ dependence at large $$b_T$$ for the evolution kernel, while preserving the accuracy of the existing fits. The results are particularly important for using transverse-spin-dependent functions like the Sivers function.
Authors:
 [1] ;  [2]
  1. Pennsylvania State Univ., University Park, PA (United States)
  2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States)
Publication Date:
OSTI Identifier:
1223378
Report Number(s):
JLAB-THY--15-2024; DOE/OR/23177--3525; arXiv:1507.05542
TRN: US1601418
DOE Contract Number:
AC05-06OR23177
Resource Type:
Conference
Resource Relation:
Conference: XXIII International Workshop on Deep-Inelastic Scattering and Related Subjects, Dallas, TX (United States), 27 Apr - 1 May 2015
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; DATA; ENERGY DEPENDENCE; FUNCTIONS; TRANSVERSE MOMENTUM; QUARKS; DENSITY; FACTORIZATION; ACCURACY; FRAGMENTATION; KERNELS