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<p><span style="orphans: 2; white-space: pre-wrap; widows: 2;">Theory Center Seminar
Wed., Nov. 30, 2016
2:00 p.m. (coffee at 1:45 p.m.)
CEBAF Center, Room L102
Fernanda Steffens
DESY
<b>Direct Calculation of PDFs in Lattice QCD</b>
Parton distributions are usually defined as light-cone correlations in the nucleon. Until recently, however, it was not possible to calculate the distributions in lattice QCD because, unlike spatial correlations, one cannot simulate light-cone correlations in a Euclidian lattice. In 2013, Ji proposed a way to circumvent this restriction, through the use of quark quasi-distributions which are defined as purely spatial correlations. Although they are not the physical distributions, the quark quasi-distributions are related to the quark distributions through a perturbative calculation. Within this procedure, a direct calculation of the distributions in lattice QCD became a possibility, and we present here a high statistics analysis of the x-dependence of the bare unpolarized, helicity and transversity iso-vector parton distribution functions (PDFs) from lattice calculations employing (maximally) twisted</span><span style="orphans: 2; white-space: pre-wrap; widows: 2;"> mass fermions. The x-dependence of the calculated PDFs resembles those of the phenomenological parameterizations, a feature that makes this approach promising despite the lack of a full renormalization program for them.</span></p>
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