Related papers: Soft-Gluon Cancellation, Phases and Factorization …
We study transverse-momentum-dependent (TMD) gluon distributions and factorization theorems for the gluon-initiated semi-inclusive processes at hadron colliders. Gauge-invariant TMD gluon distributions are defined, and their relations to…
We discuss the motivation for resummation of the effects of initial-state soft-gluon radiation, to all orders in the strong coupling strength, for processes in which the near-threshold region in the partonic subenergy is important. We…
In this paper, we show that multiple maximally soft (anti-)quark and gluon emissions exponentiate at the level of either the amplitude or cross-section. We first show that such emissions can be captured by introducing new soft emission…
A complication in proving factorization theorems in Feynman gauge is that individual graphs give a super-leading power of the hard scale when all the gluons inducing the hard scattering are longitudinally polarized. With the aid of an…
Gluon fragmentation to heavy $J^{PC}=2^{-+}$ quarkonia is studied herein. We compute these D-wave states' polarized fragmentation functions and find that they are enhanced by large numerical prefactors. The prospects for detecting the…
Motivated by the relation existing between the gluon density in a hadron and the multiplicity of the particles measured in the final state of hadron-nucleus collisions, we study systematically the fluctuations of the gluon density in onia,…
Interactions between hard partons and the quark-gluon plasma range from frequent soft interactions to rare hard scatterings. The larger number of soft interactions makes possible an effective stochastic description of parton-plasma…
We discuss the structure of infrared singularities in on-shell QCD amplitudes with massive partons and present a general factorization formula in the limit of small parton masses. The factorization formula gives rise to an all-order…
We present experimental evidences for the existence of a semi-hard scale in light hadrons. This includes the suppression of gluon radiation that is seen in high mass hadron diffraction; the weak energy dependence of hadronic total cross…
Matrix elements of Wilson-line dressed operators play a central role in the factorization of soft and collinear modes in gauge theories. When expressed using spinor helicity variables, these so-called form factors admit a classification…
We study in detail the exchange of a Coulomb (Glauber) gluon in the first few orders of QCD perturbation theory in order to shed light on their accounting to all orders. We find an elegant cancellation of graphs that imposes a precise…
Order $\alpha_s$-corrections to the diffractive structure functions $F_L^D$ and $F_2^D$ at large $Q^2$ and small $x$ are evaluated in the semiclassical approach, where the initial proton is treated as a classical colour field. The…
We consider the most general form of soft and collinear factorization for hard-scattering amplitudes to all orders in perturbative Quantum Chromodynamics. Specifically, we present the generalization of collinear factorization to…
I present a class of functions unifying all singular limits for the emission of soft or collinear gluons in gauge-theory amplitudes at any order in perturbation theory. Each function is a generalization of the antenna functions of ref. [1].…
The soft-gluon approximation, which implies that radiated gluon carries away a small fraction of initial parton's energy, is a commonly used assumption in calculating radiative energy loss of high momentum partons traversing QGP created at…
We consider the factorization properties of on-shell QCD amplitudes with massive partons in the limit when all kinematical invariants are large compared to the parton mass and discuss the structure of their infrared singularities. The…
The origin of the breaking of conventional linear k_\perp-factorization for hard processes in a nuclear environment is by now well established. The realization of the nonlinear nuclear k_\perp-factorization which emerges instead was found…
Fragmentation is the dominant mechanism for hadron production with high transverse momentum. For spin-triplet S-wave heavy quarkonium production, contribution of gluon fragmenting to color-singlet channel has been numerically calculated…
Within the colour dipole picture for deep inelastic scattering at small Bjorken $x$, we study the production of a pair of relatively hard jets via coherent diffraction. By "relatively hard" we mean that the transverse momenta of the two…
A large fraction of top quark events in $\pp$ collisions at $1.8\ \TeV$ will contain additional soft hadronic jets from gluon bremsstrahlung off the quarks and gluons in the hard processes $\qq, gg \to \tt \to \bb \ww$. These extra jets can…