arXiv subjects

B. Murdaca

Publications and source records attributed to B. Murdaca.

11 recordsLinked to original sources

arXiv2017

High energy effects in multi-jet production at LHC

We study differential cross sections for the production of three and four jets in multi-Regge kinematics, the main interest lying on azimuthal angle dependences. The theoretical setup is the jet production from a single BFKL ladder with a convolution of two/three BFKL Green functions, where two forward/backward jets are always tagged in the final state. Furthermore, we require the tagging of one/two further jets in more central regions of the detectors with a relative separation in rapidity. We found, as result, that the dependence on transverse momenta and rapidities of the central jets can be considered as a distinct signal of the onset of BFKL dynamics.

hep-ph↗

arXiv2016

Inclusive three jet production at the LHC as a new BFKL probe

We discuss recently proposed observables, sensitive to BFKL dynamics, in the context of multijet production at the large hadron collider (LHC). In particular, we consider ratios of azimuthal angle differences in final states with three jets, well separated in rapidity from each other, with two of them being very forward/backward and the third one in the central region.

hep-ph↗

arXiv2015

BFKL predictions for inclusive three jet production at the LHC

We define new observables sensitive to BFKL dynamics in the context of multijet production at the large hadron collider (LHC). We propose the study of the inclusive production of three jets well separated in rapidity from each other, with two of them being very forward. We show that the tagging of a third jet in the central region of rapidity allows for a very strong test of the BFKL formalism. In particular, we have studied two projections on azimuthal angles for the differential cross section which allow for the definition of many different observables whose behavior when varying the $p_t$ and rapidity of the central jet is a distinct signal of BFKL dynamics. In order to reduce the theoretical uncertainties and influence of higher order corrections, we propose the study of ratios of correlation functions of products of cosines of azimuthal angle differences among the tagged jets.

hep-ph↗

arXiv2014

The Mueller-Tang jet impact factor at NLO from the high energy effective action

We report on recent progress in the evaluation of next-to-leading order observables using Lipatov's QCD high energy effective action. In this contribution we focus on the determination of the real part of the next-to-leading order corrections to the Mueller-Tang impact factor which is the only missing element for a complete NLO BFKL description of quark induced dijet events with a rapidity gap.

hep-ph↗

arXiv2014

The quark induced Mueller-Tang jet impact factor at next-to-leading order

We present the NLO corrections for the quark induced forward production of a jet with an associated rapidity gap. We make use of Lipatov's QCD high energy effective action to calculate the real emission contributions to the so-called Mueller-Tang impact factor. We combine them with the previously calculated virtual corrections and verify ultraviolet and collinear finiteness of the final result.

hep-ph↗

arXiv2014

The next-to-leading order vertex for a forward jet plus a rapidity gap at high energies

We present the results for the calculation of the forward jet vertex associated to a rapidity gap (coupling of a hard pomeron to the jet) in the Balitsky-Fadin-Kuraev-Lipatov (BFKL) formalism at next-to-leading order (NLO). We handle the real emission contributions making use of the high energy effective action proposed by Lipatov, valid for multi-Regge and quasi-multi-Regge kinematics. This result is important since it allows, together with the NLO non-forward gluon Green function, to perform NLO studies of jet production in diffractive events (Mueller-Tang dijets, as a well-known example).

hep-ph↗

arXiv2013

Scale choice & collinear contributions to Mueller-Navelet jets at LHC energies

We investigate the stability under variation of the renormalization, factorization and energy scales entering the calculation of the cross section, at next-to-leading order in the BFKL formalism, for the production of Mueller-Navelet jets at the Large Hadron Collider, following the experimental cuts on the tagged jets. To find optimal values for the scales involved in this observable it is possible to look for regions of minimal sensitivity to their variation. We show that the scales found with this logic are more natural, in the sense of being more similar to the squared transverse momenta of the tagged jets, when the BFKL kernel is improved with a resummation of collinear contributions than when the treatment is at a purely next-to-leading order. We also discuss the good perturbative convergence of the ratios of azimuthal angle correlations, which are quite insensitive to collinear resummations and well described by the original BFKL framework.

hep-ph↗

arXiv2013

A study of the diffusion pattern in N=4 SYM at high energies

In the context of evolution equations and scattering amplitudes in the high energy limit of the N=4 super Yang-Mills theory we investigate in some detail the BFKL gluon Green function at next-to-leading order. In particular, we study its collinear behaviour in terms of an expansion in different angular components. We also perform a Monte Carlo simulation of the different final states contributing to such a Green function and construct the diffusion pattern into infrared and ultraviolet modes and multiplicity distributions, making emphasis in separating the gluon contributions from those of scalars and gluinos. We find that the combined role of the non-gluonic degrees of freedom is to improve the collinear behavior and reduce the diffusion into ultraviolet regions while not having any effect on the average multiplicities or diffusion into the infrared. In terms of growth with energy, the non-zero conformal spin components are mainly driven by the gluon terms in the BFKL kernel. For zero conformal spin (Pomeron) the effect of the scalar and gluino sectors is to dramatically push the Green function towards higher values.

hep-th↗

arXiv2012

Mueller-Navelet jets in high-energy hadron collisions

We consider within QCD collinear factorization the process $p+p\to {\rm jet} +{\rm jet} +X$, where two forward high-$p_T$ jets are produced with a large separation in rapidity $Δy$ (Mueller-Navelet jets [1]). The hard part of the reaction receives large higher-order corrections $\sim α^n_s (Δy)^n$, which can be accounted for in the BFKL approach. We calculate cross section and azimuthal decorrelation, using the next-to-leading order jet vertices, in the small-cone approximation [2].

hep-ph↗

arXiv2012

Applications of Lipatov's high energy effective action to NLO BFKL jet phenomenology

We report on recent progress in the evaluation of next-to-leading order (NLO) observables using Lipatov's QCD high energy effective action. We calculate both real and virtual corrections to the quark induced forward jet vertex at NLO, making use of a new regularization method and a subtraction mechanism. As a new result we determine the real part of the NLO Mueller-Tang impact factor which is the only missing element for a complete NLO BFKL description of dijet events with a rapidity gap.

hep-ph↗

arXiv2012

The next-to-leading order jet vertex for Mueller-Navelet and forward jets revisited

We recalculate, completely within the original BFKL approach and at the next-to-leading order, the jet vertex relevant for the production of Mueller-Navelet jets in proton collisions and of forward jets in DIS. We consider both processes with incoming quark and gluon. The starting point is the definition of quark and gluon impact factors in the BFKL approach. Following this procedure we show explicitly that all infrared divergences cancel when renormalized parton densities are considered. We compare our results for the vertex with the former calculation of Refs. [1,2] and, in the case of the quark contribution, clarify the discrepancy present in the literature.

hep-ph↗