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Vittorio Del Duca

Publications and source records attributed to Vittorio Del Duca.

At least 73 records · Page 4Linked to original sources
arXiv2008

Higgs production via gluon-gluon fusion with finite top mass beyond next-to-leading order

We present a computation of the cross section for inclusive Higgs production in gluon-gluon fusion for finite values of the top mass in perturbative QCD to all orders in the limit of high partonic center-of-mass energy. We show that at NLO the high energy contribution accounts for most of the difference between the result found with finite top mass and that obtained in the limit of infinite top mass. We use our result to improve the known NNLO order result obtained with infinite top mass. We estimate the effect of the high energy NNLO top mass dependence on the K factor to be of the order of a few per cent.

hep-ph↗
arXiv2007

Recursive Construction of Higgs-Plus-Multiparton Loop Amplitudes: The Last of the Phi-nite Loop Amplitudes

We consider a scalar field, such as the Higgs boson H, coupled to gluons via the effective operator H tr G_{mu nu} G^{mu nu} induced by a heavy-quark loop. We treat H as the real part of a complex field phi which couples to the self-dual part of the gluon field-strength, via the operator phi tr G_{SD mu nu} G_{SD}^{mu nu}, whereas the conjugate field phi^dagger couples to the anti-self-dual part. There are three infinite sequences of amplitudes coupling phi to quarks and gluons that vanish at tree level, and hence are finite at one loop, in the QCD coupling. Using on-shell recursion relations, we find compact expressions for these three sequences of amplitudes and discuss their analytic properties.

hep-ph↗
arXiv2006

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.

hep-ph↗
arXiv2006

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.

hep-ph↗
arXiv2005

All Non-Maximally-Helicity-Violating One-Loop Seven-Gluon Amplitudes in N=4 Super-Yang-Mills Theory

We compute the non-MHV one-loop seven-gluon amplitudes in N=4 super-Yang-Mills theory, which contain three negative-helicity gluons and four positive-helicity gluons. There are four independent color-ordered amplitudes, (- - - + + + +), (- - + - + + +), (- - + + -+ +) and (- + - + - + +). The MHV amplitudes containing two negative-helicity and five positive-helicity gluons were computed previously, so all independent one-loop seven-gluon helicity amplitudes are now known for this theory. We present partial information about an infinite sequence of next-to-MHV one-loop helicity amplitudes, with three negative-helicity and n-3 positive-helicity gluons, and the color ordering (- - - + + ... + +); we give a new coefficient of one class of integral functions entering this amplitude. We discuss the twistor-space properties of the box-integral-function coefficients in the amplitudes, which are quite simple and suggestive.

hep-th↗
arXiv2001

The high energy limit of QCD at two loops

By taking the high-energy limit of the two-loop amplitudes for parton-parton scattering, we have tested the validity of Fadin-Lipatov's ansatz for parton-parton scattering in the high-energy limit. As expected, we have found that it holds at LL and NLL accuracy, and hence we have independently re-evaluated the two-loop Regge trajectory, finding full agreement with the previous results by Fadin and collaborators. We have found, though, that the universality implied by the ansatz is violated at the next-to-next-to-leading logarithmic level.

hep-ph↗
arXiv1999

Electroweak-boson hadroproduction at large transverse momentum: factorization, resummation, and NNLO corrections

We study the resummation of singular distributions for electroweak-boson production at large transverse momentum in hadronic collisions. We describe the factorization properties of the cross section near partonic threshold and construct the resummed cross section at next-to-leading logarithmic accuracy in moment space in terms of soft gluon anomalous dimensions. We present full analytical results for the expansion of the resummed cross section up to next-to-next-to-leading order. Our results can be applied to W, Z, and virtual gamma production at hadron colliders.

hep-ph↗
arXiv1999

New Color Decompositions for Gauge Amplitudes at Tree and Loop Level

Recently, a color decomposition using structure constants was introduced for purely gluonic tree amplitudes, in a compact form involving only the linearly independent subamplitudes. We give two proofs that this decomposition holds for an arbitrary number of gluons. We also present and prove similar decompositions at one loop, both for pure gluon amplitudes and for amplitudes with an external quark-antiquark pair.

hep-ph↗
arXiv1999

Factorization of tree QCD amplitudes in the high-energy limit and in the collinear limit

In the high-energy limit, we compute the gauge-invariant three-parton forward clusters, which in the BFKL theory constitute the tree parts of the NNLO impact factors. In the triple collinear limit, we obtain the polarized double-splitting functions. For the unpolarized and the spin-correlated double-splitting functions, our results agree with the ones obtained by Campbell-Glover and Catani-Grazzini, respectively. In addition, we compute the four-gluon forward cluster, which in the BFKL theory forms the tree part of the NNNLO gluonic impact factor. In the quadruple collinear limit we obtain the unpolarized triple-splitting functions, while in the limit of a three-parton central cluster we derive the Lipatov vertex for the production of three gluons, relevant for the calculation of a BFKL ladder at NNLL accuracy. Finally, motivated by the reorganization of the color in the high-energy limit, we introduce a color decomposition of the purely gluonic tree amplitudes in terms of the linearly independent subamplitudes only.

hep-ph↗
arXiv1999

Multi-Photon Amplitudes for Next-to-Leading Order QCD

We present the tree-level amplitudes involving one, two and three photons that are required for next-to-leading order QCD calculations of production rates of three final-state particles. We also present the required one-loop amplitudes in terms of previously published results.

hep-ph↗
arXiv1999

NLL BFKL and NNLO

The BFKL resummation at LL and NLL accuracy is briefly reviewed, with particular emphasis on the connection between the NLL corrections to the BFKL equation and exact NNLO calculations.

hep-ph↗
arXiv1999

The Infrared Behavior of QCD Cross Sections at Next-to-Next-to-Leading Order

In this talk we examine how one-loop soft and collinear splitting functions occur in the calculation of next-to-next-to-leading order (NNLO) corrections to production rates, and we present the one-loop gluon soft and splitting functions, computed to all orders in the dimensional regularization parameter $ε$. We apply the one-loop gluon soft function to the calculation of the next-to-leading logarithmic corrections to the Lipatov vertex to all orders in $ε$.

hep-ph↗
arXiv1999

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.

hep-ph↗
arXiv1999

Virtual Next-to-Leading Corrections to the Lipatov Vertex

We compute the virtual next-to-leading corrections to the Lipatov vertex in the helicity-amplitude formalism. These agree with previous results by Fadin and collaborators, in the conventional dimensional-regularization scheme. We discuss the choice of reggeization scale in order to minimize its impact on the next-to-leading-logarithmic corrections to the BFKL equation.

hep-ph↗