Higgs Production at LHC

We review Higgs production at hadron colliders via vector-boson fusion and via gluon fusion, fully inclusively and in association with one and two jets. Then we address the issue of the measurement of the coupling of the Higgs to the vector bosons at LHC.Comment: 6 pages, 7 Postscript figures, uses wqcd03.cls Talk at the International Workshop on QCD: QCD@Work 2003 - Conversano (Italy) 14-18 June 2003 (eConf C030614

Theory of Double Hard Diffraction

In this review talk I consider the physics of rapidity gaps between two jets at hadron colliders, as a preliminary investigation toward understanding the production of a Higgs boson via weak boson fusion at the LHC.Comment: LaTeX, 11 pages (including 2 figures). To appear in the Proceedings of the XI Topical Workshop on P-Pbar Collider Physics, Abano Terme, Italy, May 199

QCD Amplitudes in the High-Energy Limit

Dijet production with a rapidity gap between the jets is considered as a test ground for the production of a heavy Higgs boson via weak-boson fusion at hadron supercolliders. It is argued that in order to perform a detailed analysis of dijet production with a rapidity gap we need an {\cal O}(\al_s^4) calculation including the relevant collinear enhancements which give structure to the jets. Such a calculation needs not be exact, but must include the full leading power in $\hat{s}/\hat{t}$ of the rate of dijet production in the high-energy limit. The QCD amplitudes must be determined to the corresponding accuracy. Accordingly, the scattering amplitudes necessary to compute the full leading power in $\hat{s}/\hat{t}$ of dijet production to {\cal O}(\al_s^3) are analysed.Comment: LaTeX, 18 pages. To appear in the Proceedings of LISHEP98, Rio, Brasil, February 199

Parton-Parton Elastic Scattering and Rapidity Gaps at SSC and LHC Energies

The theory of the perturbative pomeron, due to Lipatov and collaborators, is used to compute the probability of observing parton-parton elastic scattering and rapidity gaps between jets in hadron collisions at SSC and LHC energies.Comment: 7 page

Next-to-Leading Corrections to the BFKL Equation

Using the helicity formalism in the high-energy limit, we compute the amplitudes which generate the real next-to-leading-logarithmic corrections to the BFKL equation. Accordingly, we provide a list of all the off-shell vertices necessary to build such amplitudes.Comment: LaTeX, 16 pages (including 4 figures). To appear in the Proceedings of Les Rencontres de Physique de la Vallee d'Aoste, La Thuile, Val d'Aosta, Italy, March 199

Large Rapidity Gaps between Jets at HERA and at the Tevatron

In this talk I consider the formation of a rapidity gap in hadron production between two jets.Comment: LaTeX, 5 pages. To appear in the Proceedings of the International Workshop on Deep Inelastic Scattering and Related Phenomena, Roma, Italy, April 199

QCD challenges at the LHC

In this talk I review some challenges which await perturbative QCD at the Large Hadron Collider. In particular, I consider the underlying event, Monte Carlo methods and next-to-leading order (NLO) calculations.Comment: 4 pages. To appear in the proceedings of 41st Rencontres de Moriond: QCD and Hadronic Interactions, La Thuile, Italy, 18-25 Mar 200

QCD at hadron colliders

QCD is an extensively developed and tested gauge theory, which models the strong interactions in the high-energy regime. In this talk, I shall review the considerable progress which has been achieved in the last few years in the most actively studied QCD topics: Monte Carlo models, higher-order corrections, and parton distribution functions. Thanks to that, QCD in the high-energy regime is becoming more and more an essential precision toolkit to analyse Higgs and New Physics scenarios at the LHC.Comment: 12 pages, 1 figure. To appear in the proceedings of WHEPP9, Bhubaneswar, India, January 200

BFKL in forward jet production

In this talk I consider dijet production at large rapidity intervals in hadron collisions and forward-jet production in DIS as candidate signatures of a BFKL evolution. The state of the art on the measurements, and on the BFKL-motivated phenomenological analyses with emphasis on the different approximations involved, is reviewed.Comment: LaTeX, 16 pages To appear in the Proceedings of the XIIth Hadron Collider Physics Workshop, Stony Brook, NY, June 199

Quark-antiquark contribution to the multigluon amplitudes in the helicity formalism

Using the helicity formalism, we compute the contribution of a quark-antiquark pair to the tree-level multigluon amplitudes in the high-energy limit. The $\bar{q}\, q$-pair production is absent in the leading-log formalism, but contributes to the next-to-leading corrections to it, and is therefore relevant for the computation of parton-parton scattering in the high-energy limit and of the gluon anomalous dimension at small $x_{bj}$, at next-to-leading accuracy.Comment: LaTeX, 24 pages (including 5 compressed uuencoded figures