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Agustin Sabio Vera

Publications and source records attributed to Agustin Sabio Vera.

50 records · Page 3Linked to original sources
arXiv2005

W production at large transverse momentum at the Large Hadron Collider

We study the production of W bosons at large transverse momentum in pp collisions at the Large Hadron Collider (LHC). We calculate the complete next-to-leading order (NLO) corrections to the differential cross section. We find that the NLO corrections provide a large increase to the cross section but, surprisingly, do not reduce the scale dependence relative to leading order (LO). We also calculate next-to-next-to-leading-order (NNLO) soft-gluon corrections and find that, although they are small, they significantly reduce the scale dependence thus providing a more stable theoretical prediction.

hep-ph↗
arXiv2005

An "all-poles" approximation to collinear resummations in the Regge limit of perturbative QCD

The procedure to improve the convergence in transverse momentum space of the NLL BFKL kernel using a w-shift is revisited. An accurate approximation to this shift only depending on transverse momenta is presented. This approximation is based on a Bessel function of the first kind with argument depending on the strong coupling and a double logarithm of the ratio of transverse scales. A comparison between different renormalization schemes is also included.

hep-ph↗
arXiv2004

A Study of the Gluon Ladder in Diffractive Processes

The solution to the non-forward BFKL equation in the Leading Logarithmic approximation is expressed in terms of a sum of iterations of its kernel directly in transverse momentum and rapidity space. Several studies of the non-forward solution are performed both at the level of the gluon Green's function and for a toy cross-section, including an analysis of the diffusion properties as found in this approach. The method developed in this paper allows for a direct inspection of the momenta in the BFKL ladder, and can be applied to solving the non-forward BFKL equation to next-to-leading logarithmic accuracy, when the corresponding kernel is available.

hep-ph↗
arXiv2004

Production of Large Transverse Momentum W Bosons at the Tevatron

We discuss the production of W bosons at large transverse momentum in p pbar collisions at the Tevatron Run I and II. W boson hadroproduction is a process of relevance in testing the Standard Model and in estimates of backgrounds to new physics. The next-to-leading order cross section in the region of large transverse momentum is dominated by threshold soft-gluon corrections which arise from incomplete cancellations near partonic threshold between graphs with real emission and virtual graphs due to the limited phase space available for real gluon emission. In this contribution it is shown how, by including next-to-next-to-leading-order (NNLO) soft-gluon corrections, the transverse momentum distribution of the W at the Tevatron is modestly enhanced and the dependence on the factorization and renormalization scales is significantly reduced.

hep-ph↗
arXiv2004

Large-Q_T W-boson production at the Tevatron

The production of W bosons at large transverse momentum at the Tevatron is dominated by soft-gluon corrections. In this talk we present a calculation of these corrections at next-to-next-to-leading order. The corrections enhance the transverse momentum distribution of the W while reducing the scale dependence.

hep-ph↗
arXiv2004

The Gluon Green's Function in N=4 Supersymmetric Yang-Mills Theory

The high energy limit of scattering amplitudes in the N=4 supersymmetric Yang-Mills theory is studied by solving the corresponding BFKL equation in the next-to-leading approximation. The gluon Green's function is analysed using a newly proposed method suitable for investigating the contribution from higher conformal spins. From this new approach complete agreement is obtained with the results of Kotikov and Lipatov on conformal spins and angular dependence.

hep-th↗
arXiv2004

The Gluon Green's Function at Small x

In this contribution a recently proposed iterative procedure is used to study the BFKL gluon Green's function at next-to-leading order. This is done in QCD and in N=4 supersymmetric Yang-Mills theory. The study includes an analysis of the evolution with energy and of angular dependences. A discussion of a novel resummation of running coupling terms in the QCD case is included.

hep-ph↗
arXiv2004

W Boson Production at Large Transverse Momentum

The production of W bosons at large transverse momentum in p pbar collisions is studied. The next-to-leading order cross section in this region is dominated by threshold soft-gluon corrections. The transverse momentum distribution of the W at the Tevatron is modestly enhanced when next-to-next-to-leading-order soft-gluon corrections are added, and the dependence on the factorization and renormalization scales is significantly reduced.

hep-ph↗
arXiv2003

W hadroproduction at large transverse momentum beyond next-to-leading order

We study the production of W bosons at large transverse momentum in p pbar collisions. We show that the next-to-leading order cross section at large transverse momentum is dominated by threshold soft-gluon corrections. We add next-to-next-to-leading-order soft-gluon corrections to the exact next-to-leading-order differential cross sections. We find that these higher-order corrections provide modest enhancements to the transverse momentum distribution of the W at the Tevatron, and reduce significantly the dependence on the factorization and renormalization scales.

hep-ph↗
arXiv2003

The Gluon Green's Function in the BFKL Approach at Next-to-Leading Logarithmic Accuracy

We investigate the gluon Green's function in the high energy limit of QCD using a recently proposed iterative solution of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) equation at next-to-leading logarithmic (NLL) accuracy. To establish the applicability of this method in the NLL approximation we solve the BFKL equation as originally written by Fadin and Lipatov, and compare the results with previous studies in the leading logarithmic (LL) approximation.

hep-ph↗
arXiv2003

Inclusive Double Diffractive Production of SUSY Particles at the LHC

We estimate the inclusive double diffractive production of SUSY particles at the LHC using a modified version of the POMWIG Monte Carlo event generator. The diffractive events are produced via the Ingelman-Schlein model for double pomeron exchange. The MSSM parameter space is scanned using the ``Snowmass benchmark points'' and it is shown that the lightest Higgs boson is the only SUSY particle with a large enough rate to be detected using these diffractive events.

hep-ph↗
arXiv2003

Solving the BFKL Equation in the Next-to-Leading Approximation

The Balitsky-Fadin-Kuraev-Lipatov equation in the next-to-leading logarithmic approximation is solved using an iterative method. We derive the solution for forward scattering with all conformal spins. A discussion of the infrared finiteness of the results is included.

hep-ph↗
arXiv2003

Phenomenology of a SU(2) Triplet Higgs

We study the Renormalization Group evolution of the couplings in a model with a real SU(2) triplet in the Higgs sector. Insisting that the model remain valid up to 1 TeV we show that it is possible for there to be no light Higgs bosons without any otherwise dramatic deviation from the physics of the Standard Model.

hep-ph↗