TMD soft function from large-momentum effective theory

• Published in: Nuclear physics. B Vol. 955; no. C; p. 115054
• Main Authors: Ji, Xiangdong, Liu, Yizhuang, Liu, Yu-Sheng
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2020; Elsevier
• ISSN: 0550-3213; 1873-1562
• DOI: 10.1016/j.nuclphysb.2020.115054

We study Euclidean formulations of the transverse-momentum-dependent (TMD) soft function, which is a cross section for soft gluon radiations involving color charges moving in two conjugate lightcone directions in quantum chromodynamics. We show it is related to a special form factor of a pair of color sources traveling with nearly-lightlike velocities, which can be matched to TMD physical observables in semi-inclusive deep-inelastic scattering and Drell-Yan process in the framework of large momentum effective theory. It can also be extracted by combining a large-momentum form factor of light meson and its leading TMD wave function. These formulations are useful for initiating nonperturbative calculations of this useful quantity.