Related papers: k-Factorization and Impact Factors at Next-to-lead…
We first revisit impact-parameter dependent collisions of ultra-relativistic particles in quantum field theory. Two conditions sufficient for defining an impact-parameter dependent cross section are given, which could be violated in…
We discuss applications of the recently developed nonlinear k_perp--factorization for hard processes on nuclei. The starting point is the color dipole approach which allows to introduce the concept of a collective unintegrated nuclear gluon…
We compute at next-to-leading order level the impact factor for the production of a forward Higgs boson from a colliding proton. Combined with other forward impact factors, it can be used to describe, at next-to-leading logarithmic…
We consider the singular behaviour of QCD scattering amplitudes in kinematical configurations where two or more momenta of the external partons become collinear. At the tree level, this behaviour is known to be controlled by factorization…
We present some results on renormalization and factorization scale dependence of soft-gluon resummation, at the next-to-leading-logarithmic level, in the fixed-target hadro-production cross-section for prompt photons.
Threshold logarithms become dominant in partonic cross sections when the selected final state forces gluon radiation to be soft or collinear. Such radiation factorizes at the level of scattering amplitudes, and this leads to the resummation…
The behaviour of the quark coefficient functions in deep-inelastic scattering is investigated for large values of the Bjorken variable x. By combining results of soft-gluon resummation and fixed-order calculations, we determine the…
We consider QCD radiative corrections to the production of colourless high-mass systems in hadron collisions. The logarithmically-enhanced contributions at small transverse momentum are treated to all perturbative orders by a universal…
Different definitions of integrability, as a rule, use linearization of initial equation and/or expansion on some basic functions which are themselves solutions of some linear differential equation. Important fact here is that linearization…
We derive a factorization theorem for the Higgs-boson production amplitude in gluon-gluon fusion induced by a light-quark loop, working at next-to-leading power in soft-collinear effective theory. The factorization is structurally similar…
We examine the endpoint region of inclusive deep inelastic scattering at next-to-leading power (NLP). Using a soft-collinear effective theory approach with no explicit soft or collinear modes, we discuss the factorization of the cross…
We study the soft limit of one-loop QCD amplitudes and we derive the process-independent factorization formula that controls the singular behaviour in this limit. This is obtained from the customary eikonal factorization formula valid at…
We study the electromagnetic on-shell form factor of quarks in massless perturbative QCD. We derive the complete pole part in dimensional regularization at three loops, and extend the resummation of the form factor to the…
I report on progress in the calculation of one-loop amplitudes with a space-like gluon. Amplitudes with space-like partons are relevant for factorization procedure s that require initial-state partons with non-vanishing transverse momentum…
We present the third-order contributions to the quark-gluon and gluon-quark timelike splitting functions for the evolution of fragmentation functions in perturbative QCD. These quantities have been derived by studying physical evolution…
We present the next-to-leading power (NLP) factorization formula for the $q\bar{q}\to \gamma^*+X$ channel of the Drell-Yan production near the kinematic threshold limit. The formalism used for the computation of next-to-leading power…
We study deep-inelastic scattering factorization on a nucleon in the end-point regime $x_B \sim 1-{\cal O}(\Lambda_{\rm QCD}/Q)$ where the traditional operator product expansion is supposed to fail. We argue, nevertheless, that the standard…
We investigate the next-to-leading-colour (NLC) contributions to the colour matrix in the fundamental and the colour-flow decompositions for tree-level processes with all gluons, one quark pair and two quark pairs. By analytical examination…
Single inclusive hadron production at forward rapidity in high energy p+A collisions is an important probe of the high gluon density regime of QCD and the associated small-$x$ formalism. We revisit an earlier one-loop calculation to…
We consider the production of an arbitrary number of colour-singlet particles near partonic threshold, and show that next-to-leading order cross sections for this class of processes have a simple universal form at next-to-leading power…