Related papers: Resummation of threshold logarithms in deeply-virt…
We review some techniques of resummation applied to heavy quark production in hadronic scattering and electroproduction near partonic threshold, and discuss the reduction of factorization scale dependence in resummed cross sections.
We investigate the effect of large-x resummation on parton distributions by performing a fit of Deep Inelastic Scattering data from the NuTeV, BCDMS and NMC collaborations, using NLO and NLL soft-resummed coefficient functions. Our results…
We discuss the resummation of threshold logarithms for heavy quark and dijet cross sections in hadronic collisions. The resummed cross sections are presented at next-to-leading logarithmic accuracy in terms of anomalous dimension matrices…
We compute in the heavy quark effective theory the soft coefficient D_2 entering the resummation of next-to-next-to-leading threshold logarithms for jets initiated by a quark with a small mass compared to the hard scale of the process. We…
We define a general scheme for the evolution of fragmentation functions which resums soft gluon logarithms in a manner consistent with fixed order evolution. We present an explicit example of our approach in which double logarithms are…
In the collinear factorization of the form factor for the transition $\gamma^* \pi^0 \to \pi$ the hard part contains double log terms. These terms will spoil the perturbative expansion of the hard part. A simple exponentiation for…
We develop a formalism for the resummation of target mass corrections in off-forward two-photon amplitudes given by a chronological product of electromagnetic currents, arising in e.g. deeply virtual Compton scattering. The method is based…
We develop a formalism for resumming threshold double logarithms that appear in fragmentation functions for production of heavy quarkonia. Threshold singularities appear in fixed-order calculations of quarkonium fragmentation functions in…
We calculate the O(alpha_s) corrections to the timelike, spacelike and double deeply virtual Compton scattering amplitudes in the generalized Bjorken scaling region. Special attention is devoted to studies of the difference between the next…
The asymptotic behaviour at large N of the MS-bar quark anomalous dimensions is derived to all orders assuming only MS-bar factorization and standard results for the exponentiation of soft logarithms in the quark initiated bare cross…
Perturbative cross-sections in QCD are beset by logarithms of kinematic invariants, whose arguments vanish when heavy particles are produced near threshold. Contributions of this type often need to be summed to all orders in the coupling,…
We study the factorization and resummation of t-channel top quark transverse momentum distribution at large pT in the SM at both the Tevatron and the LHC with soft-collinear effective theory. The cross section in the threshold region can be…
We extend our framework for the simultaneous resummation of soft and small-mass logarithms to rapidity distributions in top quark pair production. We give numerical results for the rapidity distribution of the top quark or the anti-top…
We investigate the evolution of parton densities at small values of the momentum fraction, x, by including resummed anomalous dimensions in the renormalization group equations. The resummation takes into account the leading-logarithmic…
I discuss general unified formulas for resumming collinear and soft contributions to QCD hard scattering cross sections at large x. Expansions of the resummed cross sections to next-to-next-to-next-to-leading order are also shown along with…
We define a new variable flavour number scheme for use in deep inelastic scattering, motivated by the need to consistently implement high energy resummations alongside a fixed order QCD expansion. We define the DIS(chi) scheme at fixed…
In this paper we investigate the effect of the resummation of threshold logs on the rate for B -> X_s gamma. We calculate the differential rate dGamma/dE_gamma including the infinite set of terms of the form alpha_s^n log^{n+1}(1-x) and…
High-energy logarithmic correction are enhanced when the ratio, $x = \frac{Q^2}{s}$ between the typical energy scale of a scattering process $Q$ and the total centre of mass energy available $s$ is small. We discuss recent developments on…
We present the current status of our computation of quark bilinear renormalization constants for Wilson fermions and Symanzik improved gauge action. Computations are performed in Numerical Stochastic Perturbation Theory. Volumes range from…
We extend existing work on reparametrization invariance (RPI) of the heavy-quark expansion. We discuss the total rates of inclusive processes and obtain results which have a manifest RPI and can be expressed through matrix elements of…