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Fabio Domínguez

Publications and source records attributed to Fabio Domínguez.

4 recordsLinked to original sources

Finite Formation Time Antenna Radiation: Color Spectators Break Single-Emitter BDMPS-Z

We compute the direct contribution to the squared matrix element for the in-medium soft gluon emission off a color-singlet quark-antiquark pair. To do this, we incorporate medium interactions that take place during the finite formation time of the antenna, thereby accounting for a largely neglected source of modifications with respect to the vacuum baseline. As a consequence, non-trivial correlations with the spectator (i.e.\ non-emitting) leg of the antenna emerge, greatly increasing the complexity of the result even at leading-$N_c$ order. The observed modifications entail a significant departure from the limit of instantaneous antenna formation, where the calculation effectively reduces to the well-known BDMPS-Z spectrum.

hep-ph↗

Gluon radiation from a QCD antenna with realistic parton-medium interactions

The spectrum of coherent gluon radiation from a quark-antiquark pair undergoing multiple scatterings within a colored medium is central for understanding in-medium parton cascades. However, current efforts are constrained by reliance on a number of approximations, such as the harmonic oscillator approximation, that are only valid within limited regions of phase space. In this paper, we circumvent this problem by expressing the full in-medium gluon emission spectrum as a set of differential equations that can be solved numerically. This formalism, previously applied to the case of medium-induced radiation off a single color charge, allows to resum medium interactions to all orders while employing realistic scattering models. The resulting angle and energy distributions of emitted gluons serve to illustrate the breakdown of color coherence across the entire accessible phase-space, and constitute a definite step towards a higher-precision description of jet observables.

hep-ph↗

Non-eikonal corrections to dijet production in DIS

We compute non-eikonal corrections to dijet production in deep inelastic scattering off a nucleus. Such corrections are expected to be quantitatively important at the energies of the future Electron Ion Collider. We focus on those corrections stemming solely from the finite longitudinal size of the nucleus. For both longitudinally and transversely polarized photons, we provide general, all-order expressions in terms of two-dimensional path integrals. To proceed further, we use the harmonic oscillator approximation for the target averages of Wilson lines. We then expand the general expressions order by order beyond the shockwave limit which provides the eikonal results, up to next-to-next-to-eikonal accuracy. We observe that next-to-eikonal corrections to this observable vanish for the mentioned approximation for target averages, as previously found for single gluon production in proton-nucleus collisions. Finally, we calculate the back-to-back of correlation limit of our expressions.

hep-ph↗

A modified in-medium evolution equation with color coherence

QCD jets produced in heavy-ion collisions at LHC or RHIC energies partially evolve inside the produced hot and dense quark gluon plasma, offering unique opportunities to study QCD splitting processes in different backgrounds. Induced (modified) splittings are expected to be the most relevant mechanism driving the modifications of in-medium jets compared to vacuum jets for a wide sets of observables. Although color coherence among different emitters has been identified as an essential mechanism in studies of the {\it QCD antenna radiation}, it is usually neglected in the multi-gluon medium-induced cascade. This independent gluon emission approximation can be analytically proved to be valid in the limit of very large media, but corrections or modifications to it have not been computed before in the context of the evolution (or rate) equation describing the gluon cascade. We propose a modified evolution equation that includes corrections due to the interference of subsequent emitters. In order to do so, we first compute a modified splitting kernel following the usual procedure of factorizing it from the subsequent Brownian motion. The calculation is performed in the two-gluon configuration with no overlapping formation times, that is expected to provide the first correction to the completely independent picture.

hep-ph↗