2 research outputs found
Lattice Calculation of the Intrinsic Soft Function and the Collins-Soper Kernel
We calculate the soft function using lattice QCD in the framework of large
momentum effective theory incorporating the one-loop perturbative
contributions. The soft function is a crucial ingredient in the lattice
determination of light cone objects using transverse-momentum-dependent (TMD)
factorization. It consists of a rapidity-independent part called intrinsic soft
function and a rapidity-dependent part called Collins-Soper kernel. We have
adopted appropriate normalization when constructing the pseudo-scalar meson
form factor that is needed in the determination of the intrinsic part and
applied Fierz rearrangement to suppress the higher-twist effects. In the
calculation of CS kernel we consider a CLS ensemble other than the MILC
ensemble used in a previous study. We have also compared the applicability of
determining the CS kernel using quasi TMDWFs and quasi TMDPDFs. As an example,
the determined soft function is used to obtain the physical TMD wave functions
(WFs) of pion and unpolarized iso-vector TMD parton distribution functions
(PDFs) of proton.Comment: 24 pages, 19 figures, published versio
Unpolarized isovector quark distribution function from lattice QCD: a systematic analysis of renormalization and matching
Lattice Parton Collaboration (Liu, Yu-Sheng, et al.), "Unpolarized isovector quark distribution function from lattice QCD: a systematic analysis of renormalization and matching." Physical Review D 101 (Feb. 2020): no. 034020 doi 10.1103/PhysRevD.101.034020 ©2020 Author(s)We present a detailed lattice QCD study of the unpolarized isovector quark parton distribution function (PDF) using a large-momentum effective theory framework. We choose a quasi-PDF defined by a spatial correlator which is free from mixing with other operators of the same dimension. In the lattice simulation, we use a Gaussian-momentum-smeared source at M[subscript p]=356  MeV and P[subscript z]∈{1.8,2.3}  GeV. To control the systematics associated with the excited states, we explore five different source-sink separations. The nonperturbative renormalization is conducted in a regularization-independent momentum subtraction scheme, and the matching between the renormalized quasi-PDF and [line over MS] PDF is calculated based on perturbative QCD up to one-loop order. Systematic errors due to renormalization and perturbative matching are also analyzed in detail. Our results for light-cone PDF are in reasonable agreement with the latest phenomenological analysis. ©202