Results for "Néstor Armesto"

total 218took 0.11s
Heavy quarks in proton-nucleus collisions - the hybrid formalismNov 30 2015We explore the quark mass effects on inclusive hadron production in proton-nucleus collisions at high energies. We consider two processes. First, we compute the single inclusive cross-section for production of hadrons with open heavy flavour in the proton ... More
KLWMIJ Reggeon Field Theory beyond the large $N_c$ limitFeb 24 2014We extend the analysis of KLWMIJ evolution in terms of QCD Reggeon fields beyond leading order in the $1/N_c$ expansion. We show that there is only one type of corrections to the leading order Hamiltonian discussed in \cite{last}. These are terms linear ... More
Medium-induced soft gluon radiation in DISJul 05 2012We study color coherence effects on the medium-induced soft gluon radiation off an asymptotic quark hit by a virtual photon traversing a hot and dense QCD medium. The transverse momentum spectrum of the emitted gluon is computed at 1st order in the opacity ... More
Jet quenching as a probe of the initial stages in heavy-ion collisionsFeb 08 2019Jet quenching provides a very flexible variety of observables which are sensitive to different energy- and time-scales of the strongly interacting matter created in heavy-ion collisions. Exploiting this versatility would make jet quenching an excellent ... More
Interference between initial and final state radiation in a QCD mediumJul 04 2012Sep 19 2012We investigate the color coherence pattern between initial and final state radiation in the presence of a QCD medium. We derive the medium-induced gluon spectrum of an "asymptotic" parton which suffers a hard scattering and subsequently crosses the medium. ... More
Exclusive vector meson production at high energies and gluon saturationFeb 19 2014Aug 26 2014We systematically study exclusive diffractive (photo) production of vector mesons ($J/\psi$, $\psi(2s)$, $\phi$ and $\rho$) off protons in high-energy collisions and investigate whether the production is a sensitive probe of gluon saturation. We confront ... More
Diffractive photoproduction of vector mesons at the LHCJul 24 2014We confront saturation-based results for diffractive $\psi(2s)$ and $\rho$ production at HERA and $J/\psi$ photoproduction with all available data including recent ones from HERA, ALICE and LHCb, finding a good agreement. We show that the $t$-distribution ... More
An analysis of the influence of background subtraction and quenching on jet observables in heavy-ion collisionsNov 06 2012Feb 04 2013Subtraction of the large background in reconstruction is a key ingredient in jet studies in high-energy heavy-ion collisions at RHIC and the LHC. Here we address the question to which extent the most commonly used subtraction techniques are able to eliminate ... More
Electron-Ion Physics with the LHeCSep 09 2015Oct 01 2015The Large Hadron Electron Collider (LHeC) project is the proposal to use the existing LHC proton/ion beams and construct a new electron beam line to perform high-energy electron-proton/ion collisions. In this talk, we consider some of the physics topics ... More
Non-eikonal corrections to multi-particle production in the Color Glass CondensateFeb 12 2019We consider the non-eikonal corrections to particle production in the Color Glass Condensate stemming from the relaxation of the shockwave approximation for the target that acquires a finite longitudinal dimension. We derive a modified expression of the ... More
Medium-induced emissions of hard gluonsApr 13 2012Oct 18 2012We present a derivation of the medium-induced gluon radiation spectrum beyond the current limitation of soft gluon emission. Making use of the path integral approach to describe the propagation of high-energy particles inside a medium, we study the limiting ... More
Background subtraction and jet quenching on jet reconstructionJul 27 2012Sep 24 2012In order to assess the ability of jet observables to constrain the characteristics of the medium produced in heavy-ion collisions at the LHC, we investigate the influence of background subtraction and jet quenching on jet reconstruction, with focus on ... More
Nuclear shadowingApr 12 2006Jul 05 2006The phenomenon of shadowing of nuclear structure functions at small values of Bjorken-$x$ is analyzed. First, multiple scattering is discussed as the underlying physical mechanism. In this context three different but related approaches are presented: ... More
Introduction to Low x Physics and SaturationNov 14 2003The idea of saturation of parton densities in small x physics is briefly introduced. Some aspects of saturation are described, mainly focusing on the status of our knowledge on the non-linear equations describing the high parton density regime. Implications ... More
Nuclear Structure Functions at Small x in Multiple Scattering ApproachesMay 06 2003A simple model for nuclear structure functions in the region of small $x$ and small and moderate $Q^2$, is presented. It is a parameter-free extension, in the Glauber-Gribov approach to nuclear collisions, of a saturation model for the nucleon. A reasonable ... More
Medium-induced gluon radiation and colour decoherence beyond the soft approximationJul 02 2014Feb 12 2015We derive the in-medium gluon radiation spectrum off a quark within the path integral formalism at finite energies, including all next-to-eikonal corrections in the propagators of quarks and gluons. Results are computed for finite formation times, including ... More
Medium-induced gluon radiation beyond the eikonal approximationApr 28 2014Jul 29 2014In this work we improve existing calculations of radiative energy loss by computing corrections that implement energy-momentum conservation, previously only implemented a posteriori, in a rigorous way. Using the path-integral formalism, we compute in-medium ... More
Predictions for the heavy-ion programme at the Large Hadron ColliderMar 09 2009Jul 01 2010I review the main predictions for the heavy-ion programme at the Large Hadron Collider (LHC) at CERN, as available in early April 2009. I begin by remembering the standard claims made in view of the experimental data measured at the Super Proton Synchrotron ... More
Testing the Color Charge and Mass Dependence of Parton Energy Loss with Heavy-to-light Ratios at RHIC and LHCJan 24 2005The ratio of nuclear modification factors of high-pT heavy-flavored mesons to light-flavored hadrons (``heavy-to-light ratio'') in nucleus-nucleus collisions tests the partonic mechanism expected to underlie jet quenching. Heavy-to-light ratios are mainly ... More
Low-pT Collective Flow Induces High-pT Jet QuenchingNov 26 2004Data on low-pT hadronic spectra are widely regarded as evidence of a hydrodynamic expansion in nucleus-nucleus collisions. In this interpretation, different hadron species emerge from a common medium that has built up a strong collective velocity field. ... More
Next-to-next-to-eikonal corrections in the CGCMay 06 2015We extend the study of corrections to the eikonal approximation that was initiated in Ref. \cite{Altinoluk:2014oxa} to higher orders. These corrections associated with the finite width of the target are investigated and the gluon propagator in background ... More
Bose enhancement and the ridgeMar 24 2015Oct 26 2015We point out that Bose enhancement in a hadronic wave function generically leads to correlations between produced particles. We show explicitly, by calculating the projectile density matrix in the Color Glass Condensate approach to high-energy hadronic ... More
In-medium jet evolution: interplay between broadening and decoherence effectsDec 29 2015Feb 19 2016The description of the modifications of the coherence pattern in a parton shower, in the presence of a QGP, has been actively addressed in recent studies. Among the several achievements, finite energy corrections, transverse momentum broadening due to ... More
Towards a consistent description of in-medium parton branchingMay 25 2015Ultra-relativistic heavy-ion collisions are a window of opportunity to study QCD matter under extreme conditions of temperature and density, such as the quark-gluon plasma. Among the several possibilities, the study of jet quenching - generic name given ... More
Energy loss and (de)coherence effects beyond eikonal approximationJul 30 2014Oct 21 2014The parton branching process is known to be modified in the presence of a medium. Colour decoherence processes are known to determine the process of energy loss when the density of the medium is large enough to break the correlations between partons emitted ... More
Diffractive Dijet Production in Deep Inelastic Scattering and Photon-Hadron Collisions in the Color Glass CondensateNov 23 2015May 12 2016We study exclusive dijet production in coherent diffractive processes in deep inelastic scattering and real (and virtual) photon-hadron ($\gamma^{(*)}$-h) collisions in the Color Glass Condensate formalism at leading order. We show that the diffractive ... More
Predictions for the LHC: an OverviewApr 25 2008I present an overview of predictions for the heavy ion program at the Large Hadron Collider. It is mainly based on the material presented during the workshop 'Heavy Ion Collisions at the LHC - Last Call for Predictions', held in the frame of the CERN ... More
A simple model for nuclear structure functions at small $x$ in the dipole pictureJun 03 2002Jul 03 2002A simple model for nuclear structure functions in the region of small x and small and moderate $Q^2$, is presented. It is a parameter-free extension, in the Glauber-Gribov approach to nuclear collisions, of a saturation model for the nucleon. A reasonable ... More
Flow effects on jet profiles and multiplicitiesJan 24 2005We study the effects of low-$p_T$ collective flow on radiative energy loss from high-$p_T$ partons traversing the QCD medium created in high-energy nucleus-nucleus collisions. We illustrate this idea through three examples. Due to longitudinal flow, jet ... More
Review of Monte Carlo methods for particle multiplicity evaluationOct 12 2004I present a brief review of the existing models for particle multiplicity evaluation in heavy ion collisions which are at our disposal in the form of Monte Carlo simulators. Models are classified according to the physical mechanisms with which they try ... More
Jet quenchingOct 12 2004Jet quenching studies play a prominent role in our current understanding of ultra-relativistic heavy ion collisions. In this review I first present the available formalism to compute medium-induced gluon radiation. Then I discuss its effect on single ... More
Nuclear effects in QCDMar 31 1998Apr 01 1998Production of Drell-Yan pairs and open and hidden heavy flavor on nuclear targets is examined within perturbative QCD. The effects of modifications of nucleon structure functions inside the nuclear medium are considered. Besides, nuclear dependence of ... More
Limb-darkening and exoplanets II: Choosing the Best Law for Optimal Retrieval of Transit ParametersJan 21 2016Jan 28 2016Very precise measurements of exoplanet transit lightcurves both from ground and space based observatories make it now possible to fit the limb-darkening coefficients in the transit-fitting procedure rather than fix them to theoretical values. This strategy ... More
Limb darkening and exoplanets: testing stellar model atmospheres and identifying biases in transit parametersMar 24 2015Apr 01 2015Limb-darkening is fundamental in determining transit lightcurve shapes, and is typically modeled by a variety of laws that parametrize the intensity profile of the star that is being transited. Confronted with a transit lightcurve, some authors fix the ... More
Heavy-ion collisions at the Large Hadron Collider: a review of the results from Run 1Nov 06 2015We present an overview of the results obtained in pPb and PbPb collisions at the Large Hadron Collider during Run 1. We first discuss the results for global characteristics: cross sections, hadron multiplicities, azimuthal asymmetries, correlations at ... More
Interpretations of $J/ψ$ suppressionJun 23 1997We review the two main interpretations of $J/\psi$ suppression proposed in the literature. The phase transition (or deconfining) scenario assumes that below some critical value of the local energy density (or of some other geometrical quantity which depends ... More
Conformal diagrams for the gravitational collapse of a spherical dust cloudJun 13 2011Oct 26 2011We present an algorithm for the construction of conformal coordinates in the interior of a spherically symmetric, collapsing matter cloud in general relativity. This algorithm is based on the numerical integration of the radial null geodesics and a local ... More
Conformal diagrams for the gravitational collapse of a spherically symmetric dust cloudApr 19 2012We present an algorithm for the construction of conformal coordinates in the interior of a spherically symmetric, collapsing matter cloud in general relativity. This algorithm is based on the numerical integration of radial null geodesics. As an application ... More
On convex functions and the finite element methodApr 10 2008Many problems of theoretical and practical interest involve finding a convex or concave function. For instance, optimization problems such as finding the projection on the convex functions in $H^k(\Omega)$, or some problems in economics. In the continuous ... More
Cauchy horizon stability in a collapsing spherical dust cloud I: geometric optic approximation and spherically symmetric test fieldsNov 01 2013A spherical dust cloud which is initially at rest and which has a monotonously decaying density profile collapses and forms a shell-focussing singularity. Provided the density profile is not too flat, meaning that its second radial derivative is negative ... More
Geometry of the moduli of parabolic bundles on elliptic curvesNov 16 2016The goal of this paper is the study of simple rank 2 parabolic vector bundles over a $2$-punctured elliptic curve $C$. We show that the moduli space of these bundles is a non-separated gluing of two charts isomorphic to $\mathbb{P}^1 \times \mathbb{P}^1$. ... More
Broadening in Medium-induced QCD Radiation off a $q {\bar q}$ AntennaAug 26 2011In this contribution, the one-gluon radiation spectrum off a massive quark-antiquark ($q {\bar q}$) antenna traversing a QCD medium is calculated in the eikonal approximation. The interference between emissions from the quark and the antiquark is considered. ... More
Mass effect and coherence in medium-induced QCD radiation off a $q {\bar q}$ antennaJul 01 2011The medium-induced one-gluon radiation spectrum off a massive quark-antiquark ($q {\bar q}$) antenna traversing a colored QCD medium is calculated in this contribution. The gluon spectrum off the antenna computed at first order in the opacity expansion ... More
Coherence effects and broadening in medium-induced QCD radiation off a massive $q {\bar q}$ antennaOct 19 2011Studies of medium-induced QCD radiation usually rely on the calculation of single-gluon radiation spectrum off an energetic parton traversing an extended colored medium. Recently, the importance of interference effects between emitters in the medium has ... More
Next-to-eikonal corrections in the CGC: gluon production and spin asymmetries in pA collisionsApr 08 2014May 05 2014We present a new method to systematically include corrections to the eikonal approximation in the background field formalism. Specifically, we calculate the subleading, power-suppressed corrections due to the finite width of the target or the finite energy ... More
Nuclear PDFs from the LHeC perspectiveJun 11 2013We study the prospects for constraining the nuclear parton distribution functions by small-x deep inelastic scattering. Performing a global fit of nuclear parton distribution functions including a sample of pseudodata representing expected measurements ... More
In-medium antenna radiation in t-channelJul 06 2012The color coherence effects in the medium modification to the initial state radiation are studied via a simple setup which allows these effects to be pronounced. The medium-induced gluon radiation spectrum off a hard quark which suffers a highly virtual ... More
Energy versus centrality dependence of the jet quenching parameter $\hat q$ at RHIC and LHC: a new puzzle?Jun 15 2016Aug 12 2016The central goal of jet quenching studies in high-energy nuclear collisions is the characterization of those QCD medium properties that are accessible by these probes. Most of the discussion in the last years has been focused on the determination of the ... More
Coherence and broadening effects in medium induced gluon radiationSep 11 2012Sep 21 2012Interferences between different emitters in the multi-parton shower is the building block of QCD jet physics in vacuum. The presence of a hot medium made of quarks and gluons is expected to alter this interference pattern. To study such effects, we derive ... More
Coherence phenomena between initial and final state radiation in a dense QCD mediumAug 09 2013Nov 22 2013In this work we investigate medium modifications to the interference pattern between initial and final state radiation. We compute single gluon production off a highly energetic parton that undergoes a hard scattering and subsequently crosses a dense ... More
An analysis of the impact of LHC Run I proton-lead data on nuclear parton densitiesDec 04 2015We report on an analysis of the impact of available experimental data on hard processes in proton-lead collisions during Run I at the Large Hadron Collider on nuclear modifications of parton distribution functions. Our analysis is restricted to the EPS09 ... More
Tuning High-Harmonic Generation by Controlled Deposition of Ultrathin Ionic Layers on Metal SurfacesApr 25 2016High harmonic generation (HHG) from semiconductors and insulators has become a very active area of research due to its great potential for developing compact HHG devices. Here we show that by growing monolayers (ML) of insulators on single-crystal metal ... More
Jet and Dijet Rates in pA CollisionsNov 20 2002Nov 21 2002Jet and dijet rates in pA collisions at LHC energies are computed using a NLO Monte Carlo code. Uncertainties due to the choice of scale, jet-finding algorithm, nucleon parton densities and nuclear modifications of nucleon parton densities are analyzed. ... More
Central rapidity densities of charged particles at RHIC and LHCFeb 15 2000Predictions on central rapidity densities of charged particles at energies of the Relativistic Heavy Ion Collider and the Large Hadron Collider, for central collisions between the largest nuclei that will be available at these accelerators, are reviewed. ... More
A quantitative reanalysis of charmonium suppression in nuclear collisionsMay 09 1997Apr 28 1998We present a quantitative description of $J/\psi$ and $\psi^\prime$ suppression in proton-nucleus and nucleus-nucleus collisions at CERN energies. We use a conventional hadronic framework based on nuclear absorption plus final state interaction of the ... More
The pomeron-pomeron interaction in the perturbative QCDJun 12 1996The pomeron-pomeron interaction is studied in the perturbative approach of BFKL-Bartels. The total pomeron-pomeron cross-section is proportional to $\alpha_{s}^{4}s^{\Delta}/\sqrt {t_{1}t_{2}}$ where $\sqrt{s}$ is the c.m. energy and $t_{1,2}$ are the ... More
On the odderon intercept in perturbative QCDMar 04 1996Mar 13 1996Arguments are presented for the odderon intercept being exactly equal to unity. A variational method is presented based on a complete system of one-gluon functions. For the odderon, the highest intercept calculated by this method is $1-(3\alpha_{s}/\pi)\,0.45$. ... More
On the odderon intercept in QCDAug 09 1997The odderon singularity is studied in perturbative QCD in the framework of the Bartels-Kwieci\'nski-Praszalowicz (BKP) equation. Arguments for the odderon intercept being exactly equal to unity are given. Besides, a variational method based on a complete ... More
Approximating optimization problems over convex functionsApr 10 2008Many problems of theoretical and practical interest involve finding an optimum over a family of convex functions. For instance, finding the projection on the convex functions in $H^k(\Omega)$, and optimizing functionals arising from some problems in economics. ... More
On correlations and discreteness in non-linear QCD evolutionJan 17 2006May 16 2006We consider modifications of the standard non-linear QCD evolution in an attempt to account for some of the missing ingredients discussed recently, such as correlations, discreteness in gluon emission and Pomeron loops. The evolution is numerically performed ... More
The EMC effect at low x in perturbative QCDMar 19 1996The EMC effect is studied in the perturbative QCD hard pomeron approach. In the limit $x\rightarrow 0$ and for a nucleus with a constant density the effect is found to be a function of a single variable which combines its $x$-, $Q$- and $A$-dependence. ... More
Gluon distributions in nuclei at small x: guidance from different modelsJan 23 2003Different approaches to gluon shadowing at small x are reviewed. Some available results relevant for RHIC and LHC are compared.
The Intercept of Symmetric Multigluon Configurations in the Variational ApproachOct 31 1994To calculate the intercept of the multigluon system in a symmetric spatial configuration a variational method is developed based on a complete system of one-gluon functions. The method is applied to two- and three- gluon cases to compare with the known ... More
Nuclear Structure Functions and Heavy Flavour Leptoproduction Off the Nucleus at Small x in Perturbative QCDJul 10 2001Sep 25 2001Nuclear structure functions and cross-sections for heavy flavour production in lepton-nucleus collisions are investigated in the low $x$ region accessible now or in the near future. The scattering on a heavy nucleus is described by the sum of fan diagrams ... More
Parton densities and dipole cross-sections at small x in large nucleiApr 03 2001Apr 26 2001Unintegrated gluon densities in nuclei, dipole-nucleus cross-sections and quark densities are numerically investigated in the high-colour limit, with the scattering on a heavy nucleus exactly described by the sum of fan diagrams of BFKL pomerons. The ... More
A geometrical estimation of saturation of partonic densitiesNov 28 2000Sep 20 2001We propose a new criterium for saturation of the density of partons both in nucleons and nuclei. It is applicable to any multiple scattering model which would be used to compute the number of strings exchanged in $ep$ and $eA$ collisions. The criterium ... More
Linear perturbations of self-gravitating spherically symmetric configurationsSep 17 2012Jan 11 2013We present a new covariant, gauge-invariant formalism describing linear metric perturbation fields on any spherically symmetric background in general relativity. The advantage of this formalism relies in the fact that it does not require a decomposition ... More
Observational distinction between black holes and naked singularities: the role of the redshift functionJan 17 2014Nov 29 2015We suggest that the redshift of photons traveling from past to future null infinity through a collapsing object could provide an observational signature capable of differentiating between the formation of a globally naked singularity and the formation ... More
On the long-range correlations in hadron-nucleus collisionsFeb 21 2007Mar 14 2007Long-range correlations between multiplicities in different rapidity windows in hadron-nucleus collisions are analyzed. After recalling the standard results in the probabilistic model, we study them in the framework of perturbative QCD. Considering interacting ... More
Global Crustal Dynamics of Magnetars in Relation to their Bright X-ray OutburstsAug 08 2016This paper considers the yielding response of a neutron star crust to smooth, unbalanced Maxwell stresses imposed at the core-crust boundary, and the coupling of the dynamic crust to the external magnetic field. Stress buildup and yielding in a magnetar ... More
Medium dependence of multiplicity distributions in MLLASep 25 2008We study the modification of the multiplicity distributions in MLLA due to the presence of a QCD medium. The medium is introduced though a multiplicative constant ($f_{med}$) in the soft infrared parts of the kernels of QCD evolution equations. Using ... More
Q-PYTHIA - a Monte Carlo implementation for jet quenchingJun 03 2009RHIC experiments have established jet quenching as a fundamental tool in the study of hot matter in heavy-ion collisions. The energy reached is enough for high-pT inclusive particle studies and one- or two-particle correlations up to pT= 10-20 GeV. The ... More
Jet quenching at finite `t Hooft coupling and chemical potential from AdS/CFTJun 22 2006Jul 03 2006Following the nonperturbative prescription for the jet quenching parameter recently proposed by Liu, Rajagopal and Wiedemann, we compute the first correction in the inverse `t Hooft coupling corresponding to string alpha' corrections in the dual background. ... More
Non Classical Rotational Inertia Fraction in a One Dimensional Model of SupersolidOct 17 2011We study the rotational inertia of a model of supersolid in the frame of the mean field Gross-Pitaevskii theory in one space dimension. We discuss the ground state of the model and the existence of a non classical inertia (NCRI) under rotation that models ... More
Charmonium Suppression in Lead-Lead Collisions: Is There a Break in the $J/ψ$ Cross-Section?Jul 06 1998Oct 23 1998In the framework of a model based on nuclear absorption plus comover interaction, we compute the $E_{T}$ distribution of the $J/\psi$ in $PbPb$ collisions at SPS and compare it with available NA50 data. Our analysis suggests that the existence of new ... More
On the 2nd Order Corrections to the Hard Pomeron and the Running Coupling ConstantAug 17 1998It is shown that solutions to the 2nd order BFKL eigenvalue equation exist for arbitrary large real values of the complex angular momentum $j$. This corresponds to a cut in the complex $j$ plane along the whole real axis, and it makes the use of the complex ... More
Long Range Forward-Backward Correlations and the Color Glass CondensateJul 31 2006We discuss forward-backward correlations in the mutliplicity of produced particles in heavy ion collisions. We find the Color Glass Condensate generates distinctive predictions for the long range component of this correlation. In particular, we predict ... More
Implementation of a medium-modified parton shower algorithmSep 25 2008We present a Monte Carlo implementation of medium-induced gluon radiation in the final-state branching process. Medium effects are introduced through an additive term in the splitting functions. We have implemented such modification within PYTHIA. We ... More
Highly compact neutron stars in scalar-tensor theories of gravity: Spontaneous scalarization versus gravitational collapseApr 14 2016Jun 22 2016Scalar-tensor theories of gravity are extensions of General Relativity (GR) including an extra, nonminimally coupled scalar degree of freedom. A wide class of these theories, albeit indistinguishable from GR in the weak field regime, predicts a radically ... More
On the behaviour of non-radial null geodesics in self-similar Tolman-Bondi collapseMar 28 2015Motivated by recent work on the structure of the singularity in inhomogeneous Tolman-Bondi collapse models, we investigate the behaviour of null geodesics in the particular case where the collapse is self-similar. The presence of the homothetic Killing ... More
Shadow of a naked singularityMay 26 2015Sep 09 2015We analyze the redshift suffered by photons originating from an external source, traversing a collapsing dust cloud and finally being received by an asymptotic observer. In addition, we study the shadow that the collapsing cloud casts on the sky of the ... More
CERES: A Set of Automated Reduction Routines for Echelle SpectraSep 08 2016We present the Collection of Extraction Routines for Echelle Spectra (CERES). These routines were developed for the construction of automated pipelines for the reduction, extraction and analysis of spectra acquired with different instruments, allowing ... More
Analysis of the first RHIC results in the String Fusion ModelApr 25 2001Jan 08 2002First results from RHIC on charged multiplicities, evolution of multiplicities with centrality, particle ratios and transverse momentum distributions in central and minimum bias collisions, are analyzed in a string model which includes hard collisions, ... More
Monte Carlo for Jet Showers in the MediumJul 27 2009Oct 04 2009The most commonly employed formalisms of radiative energy loss have been derived in the high- energy approximation. In its present form, it is reliable only for the medium modifications of inclusive particle spectra. Modifications to this formalism are ... More
Jet and Dijet Rates in AB CollisionsNov 20 2002Nov 21 2002Jet and dijet rates in AB collisions at LHC energies are computed using a NLO Monte Carlo code. Uncertainties due to nuclear modifications of nucleon parton densities are analyzed. Predictions for different AB collisions at LHC energies are presented. ... More
BEAUTY HADRON PRODUCTION AT HERA-B ENERGY IN DUAL PARTON MODELSJun 01 1995Jun 02 1995Production of charmed and beauty mesons and baryons in hadron-nucleon collisions at not very high energy is considered in the framework of the Quark-Gluon String Model. We take into account the possible corrections to the model which disappear at asymptotically ... More
A unitarized model of inclusive and diffractive DIS with Q2-evolutionJan 18 2010We discuss the interplay of low-x physics and QCD scaling violations by extending the unified approach describing inclusive structure functions and diffractive production in $\gamma* p$ interactions proposed in previous papers, to large values of Q2. ... More
Relating high-energy lepton-hadron, proton-nucleus and nucleus-nucleus collisions through geometric scalingJul 01 2004A characteristic feature of small-x lepton-proton data from HERA is geometric scaling -- the fact that over a wide range of x and Q^2 all data can be described by a single variable $Q^2/Q_{sat}^2(x)$, with all x-dependence encoded in the so-called saturation ... More
Charged Current Neutrino Cross Section and Tau Energy Loss at Ultra-High EnergiesSep 27 2007Oct 02 2007We evaluate both the tau lepton energy loss produced by photonuclear interactions and the neutrino charged current cross section at ultra-high energies, relevant to neutrino bounds with Earth-skimming tau neutrinos, using different theoretical and phenomenological ... More
Inclusive diffraction at the LHeC and FCC-ehJan 25 2019We analyse the possibilities for the study of inclusive diffraction offered by future electron-proton/nucleus colliders in the TeV regime, the Large Hadron-electron Collider as an upgrade of the HL-LHC and the Future Circular Collider in electron-hadron ... More
Dynamic screening of an ion in a degenerate electron gas within the second-order Born approximationJul 10 2014The dynamic Friedel sum rule (FSR) is derived within the second-order Born (B2) approximation for an ion that moves in a fully degenerate electron gas and for an arbitrary spherically-symmetric electron-ion interaction potential. This results in an implicit ... More
Small-x Physics and the Detection of UHE NeutrinosMay 15 2008We evaluate both the tau lepton energy loss produced by photonuclear interactions and the neutrino charged current cross section at ultra-high energies, both relevant to neutrino bounds with Earth-skimming tau neutrinos.
Vertex adjacencies in the set covering polyhedronJun 23 2014Nov 10 2015We describe the adjacency of vertices of the (unbounded version of the) set covering polyhedron, in a similar way to the description given by Chv\'atal for the stable set polytope. We find a sufficient condition for adjacency, and characterize it with ... More
Baryon and strangeness enhancement at SPS, RHIC and LHC energies in the String Fusion ModelDec 20 2000Strangeness and baryon enhancement in heavy ion collisions are discussed in the framework of the String Fusion Model. The Monte Carlo version of this model is shown to reasonably reproduce three of the features that have been pointed out as evidences ... More
Monte Carlo model for nuclear collisions from SPS to LHC energiesMar 06 2001A Monte Carlo model to simulate nuclear collisions in the energy range going from SPS to LHC, is presented. The model includes in its initial stage both soft and semihard components, which lead to the formation of color strings. Collectivity is taken ... More
Percolation approach to Quark Gluon Plasma and $J/ψ$ suppressionJul 04 1996It is shown that the critical threshold for percolation of the overlapping strings exchanged in heavy ion collisions can naturally explain the sharp strong suppresion of $J/\psi$ shown by the experimental data on central Pb--Pb collisions, which does ... More
Kinematic biases on centrality selection of jet events in pPb collisions at the LHCFeb 10 2015Centrality selection has been observed to have a large effect on jet observables in pPb collisions at the Large Hadron Collider, stronger than that predicted by the nuclear modification of parton densities. We study to which extent simple considerations ... More
The diffeomorphism group of a Lie foliationDec 13 2008We explicitly compute the diffeomorphism group of several types of linear foliations (with dense leaves) on the torus $T^n$, $n\geq 2$, namely codimension one foliations, flows, and the so-called non-quadratic foliations. We show in particular that non-quadratic ... More
Initial data giving rise to naked singularities in spherically symmetric dust collapseApr 19 2012Sep 12 2012The phase space corresponding to a particular four-parameter family of initial data for the gravitational collapse of a spherically symmetric dust cloud is investigated. In a certain limit of the parameters, this family reproduces the case of homogenous ... More
$J/Ψ$ suppression at SPS, RHIC and LHC energies and the percolation of stringsJul 31 2001We study the enhancement of $c \bar c$ pair production that takes place in central heavy ion collisions due to the formation of clusters of strings. These clusters produce heavy flavors more efficiently due to their higher color. We discuss the competition ... More