209 research outputs found
Evolution and dynamics of cusped light-like Wilson loops
We discuss the possible relation between the singular structure of TMDs on
the light-cone and the geometrical behaviour of rectangular Wilson loops.Comment: 6 pages, proceedings for the 3rd Workshop on the QCD Structure of the
Nucleon (QCD-N'12
Piecewise Linear Wilson lines
Wilson lines, being comparators that render non-local operator products gauge
invariant, are extensively used in QCD calculations, especially in small-
calculations, calculations concerning validation of factorisation schemes and
in calculations for constructing or modelling parton density functions. We
develop an algorithm to express piecewise path ordered exponentials as path
ordered integrals over the separate segments, and apply it on linear segments,
reducing the number of diagrams needed to be calculated. We show how different
linear path topologies can be related using their colour structure. This
framework allows one to easily switch results between different Wilson line
structures, which is especially useful when testing different structures
against each other, e.g. when checking universality properties of
non-perturbative objects.Comment: Proceedings for Transversity 2014, 6 page
Working With Wilson Lines
We present an algorithm to express Wilson lines that are defined on piecewise
linear paths in function of their individual segments, reducing the number of
diagrams needed to be calculated. The important step lies in the observation
that different linear path topologies can be related to each other using their
color structure. This framework allows one to easily switch results between
different Wilson line topologies, which is helpful when testing different
structures against each other.Comment: Proceedings for SPIN 2014, 6 page
Loop space and evolution of the light-like Wilson polygons
We address a connection between the energy evolution of the polygonal
light-like Wilson exponentials and the geometry of the loop space with the
gauge invariant Wilson loops of a variety of shapes being the fundamental
degrees of freedom. The renormalization properties and the differential area
evolution of these Wilson polygons are studied by making use of the universal
Schwinger quantum dynamical approach. We discuss the appropriateness of the
dynamical differential equations in the loop space to the study of the energy
evolution of the collinear and transverse-momentum dependent parton
distribution functions.Comment: 8 pages, 2 eps figures; needs ws-ijmpcs.cls (supplied). Invited talk
presented at the QCD Evolution Workshop, May 14 - 17 (2012), Thomas Jefferson
National Accelerator Facility, Newport News (VA), US
Cusped light-like Wilson loops in gauge theories
We propose and discuss a new approach to the analysis of the correlation
functions which contain light-like Wilson lines or loops, the latter being
cusped in addition. The objects of interest are therefore the light-like Wilson
null-polygons, the soft factors of the parton distribution and fragmentation
functions, high-energy scattering amplitudes in the eikonal approximation,
gravitational Wilson lines, etc. Our method is based on a generalization of the
universal quantum dynamical principle by J. Schwinger and allows one to take
care of extra singularities emerging due to light-like or semi-light-like
cusps. We show that such Wilson loops obey a differential equation which
connects the area variations and renormalization group behavior of those
objects and discuss the possible relation between geometrical structure of the
loop space and area evolution of the light-like cusped Wilson loops.Comment: Invited mini-review article to Physics of Particles and Nuclei. 16
pages, 9 eps figures; v2: references style changed, citations corrected and
update
Evolution and Dynamics of Cusped Light-Like Wilson Loops in Loop Space
We discuss the possible relation between the singular structure of TMDs on
the light-cone and the geometrical behaviour of rectangular Wilson loops.Comment: Proceedings for Diffraction 2012, Lanzarote, Spain. 5 pages, 2
figure
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