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SUMMARY:Perturbative investigation of ''Wilson-line"-type operators in Par
ton Physics
DTSTART;VALUE=DATE-TIME:20180805T143000Z
DTEND;VALUE=DATE-TIME:20180805T150000Z
DTSTAMP;VALUE=DATE-TIME:20191122T082529Z
UID:indico-contribution-3043275@indico.cern.ch
DESCRIPTION:Speakers: Gregoris Spanoudes (University of Cyprus)\nWe consid
er a class of gauge-invariant nonlocal quark bilinear operators\, includin
g a finite-length Wilson-line (called Wilson-line operators). The matrix e
lements of these operators are involved in the recent "quasi-distribution"
approach for computing parton distributions nonperturbatively. \n\nIn thi
s work\, we study the renormalization of two types of classes of Wilson-li
ne operators: straight-line and "staple" operators\, which are related to
the parton distribution functions (PDFs) and transverse momentum-dependent
distributions (TMDs) respectively. In particular\, we calculate in Dimens
ional Regularization (DR)\, the 1-loop conversion factors of straight-line
operators between RI' (appropriate for nonperturbative renormalization on
the lattice) and MS-bar (typically used in phenomenology) schemes for mas
sive quarks\, as well as the 1-loop conversion factors of staple operators
for massless quarks. We also compute the RI' renormalization factors of s
taple operators on the lattice\, up to 1-loop level\, using Wilson/clover
fermions and Symanzik improved gluons. \n\nA nontrivial aspect in the reno
rmalization of such operators is the observed operator mixing\, which is d
isentangled by introducing mixing matrices. The combination of the calcula
ted conversion factors with the nonperturbative RI'-renormalized lattice c
alculation of a quasi distribution\, as well as the matching formula betwe
en the quasi distribution and the corresponding physical distribution\, co
mputed in MS-bar\, leads to a nonperturbative lattice estimate of a parton
distribution.\n\nhttps://indico.cern.ch/event/648004/contributions/304327
5/
LOCATION:Arts Bldg. Hall A
URL:https://indico.cern.ch/event/648004/contributions/3043275/
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