84 research outputs found
Factorization and Effective Action for High-Energy Scattering in QCD
I demonstrate that the amplitude of the high-energy scattering can be
factorized in a convolution of the contributions due to fast and slow fields.
The fast and slow fields interact by means of Wilson-line operators -- infinite
gauge factors ordered along the straight line. The resulting factorization
formula gives a starting point for a new approach to the effective action for
high-energy scattering.Comment: Talk presented at the workshop "Continuous Advances in QCD",
(Minneapolis), April 1998. 15 pages, 3 eps figures, Latex using sprocl.sty
and psfig.te
Factorization for high-energy scattering
I demonstrate that the amplitude of the high-energy scattering can be
factorized in a product of two independent functional integrals over "fast" and
"slow" fields which interact by means of Wilson-line operators -- gauge factors
ordered along the straight lines.Comment: 4 pages, Latex, 1 postscript figure, to appear in PR
Rapidity factorization and evolution of gluon TMDs
I discuss how the rapidity evolution of gluon transverse momentum dependent
distribution changes from nonlinear evolution at small to linear
evolution at moderate .Comment: 10 pages, contribution to Proceedings of QCD Evolution Workshop 201
Scattering of color dipoles: from low to high energies
A dipole-dipole scattering amplitude is calculated exactly in the first two
orders of perturbation theory. This amplitude is an analytic function of the
relative energy and the dipoles' sizes. The cross section of the dipole-dipole
scattering approaches the high-energy BFKL asymptotics starting from a
relatively large rapidity .Comment: 13 pages, 10 postscript figures, typos correcte
Photon impact factor in the next-to-leading order
An analytic coordinate-space expression for the next-to-leading order photon
impact factor for small- deep inelastic scattering is calculated using the
operator expansion in Wilson lines.Comment: 5 pages, 3 figure
Rapidity evolution of Wilson lines at the next-to-leading order
At high energies particles move very fast so the proper degrees of freedom
for the fast gluons moving along the straight lines are Wilson-line operators -
infinite gauge factors ordered along the line. In the framework of operator
expansion in Wilson lines the energy dependence of the amplitudes is determined
by the rapidity evolution of Wilson lines. We present the next-to-leading order
hierarchy of the evolution equations for Wilson-line operators.Comment: 5 pages and 2 figures, PRD version with typos correcte
High-enegy effective action from scattering of QCD shock waves
At high energies, the relevant degrees of freedom are Wilson lines - infinite
gauge links ordered along straight lines collinear to the velocities of
colliding particles. The effective action for these Wilson lines is determined
by the scattering of QCD shock waves. I develop the symmetric expansion of the
effective action in powers of strength of one of the shock waves and calculate
the leading term of the series. The corresponding first-order effective action,
symmetric with respect to projectile and target, includes both up and down fan
diagrams and pomeron loops.Comment: 15 pages, 10 eps figure
High-energy amplitudes in N=4 SYM in the next-to-leading order
The high-energy behavior of the N=4 SYM amplitudes in the Regge limit can be
calculated order by order in perturbation theory using the high-energy operator
expansion in Wilson lines. At large , a typical four-point amplitude is
determined by a single BFKL pomeron. The conformal structure of the four-point
amplitude is fixed in terms of two functions: pomeron intercept and the
coefficient function in front of the pomeron (the product of two residues). The
pomeron intercept is universal while the coefficient function depends on the
correlator in question. The intercept is known in the first two orders in
coupling constant: BFKL intercept and NLO BFKL intercept calculated in Ref. 1.
As an example of using the Wilson-line OPE, we calculate the coefficient
function in front of the pomeron for the correlator of four currents in
the first two orders in perturbation theory.Comment: 10 pages, 3 figure
NLO evolution of color dipoles
The small- deep inelastic scattering in the saturation region is governed
by the non-linear evolution of Wilson-line operators. In the leading
logarithmic approximation it is given by the BK equation for the evolution of
color dipoles. In the next-to-leading order the BK equation gets contributions
from quark and gluon loops as well as from the tree gluon diagrams with
quadratic and cubic nonlinearities. We calculate the gluon contribution to
small-x evolution of Wilson lines (the quark part was obtained earlier).Comment: 43 pages, 12 figure
Evolution of Conformal Color Dipoles and High Energy Amplitudes in = 4 SYM
The high-energy behavior of the = 4 SYM amplitudes in the Regge limit can be calculated order by order in perturbation theory using the high-energy operator expansion in Wilson lines. At large Nc, a typical four-point amplitude is determined by a single BFKL pomeron. The conformal structure of the four-point amplitude is fixed in terms of two functions: pomeron intercept and the coefficient function in front of the pomeron (the product of two residues). The pomeron intercept is universal while the coefficient function depends on the correlator in question. The intercept is known in the first two orders in coupling constant: BFKL intercept and NLO BFKL intercept calculated in Ref. [1]. As an example of using the Wilson-line OPE, we calculate the coefficient function in front of the pomeron for the correlator of four Z2 currents in the first two orders in perturbation theory
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