arXiv subjects

G. Sampaio dos Santos

Publications and source records attributed to G. Sampaio dos Santos.

15 recordsLinked to original sources

arXiv2023

Double charmed meson production in $pp$ and $pA$ collisions at the LHC within the dipole approach in momentum representation

A study of double charmed meson production in proton-proton and proton-nucleus collisions at the LHC energies is performed. Based on the color dipole formalism developed in the transverse momentum representation and the double parton scattering mechanism, predictions are made for the transverse momentum differential cross section for different pairs of $D$-mesons. The theoretical results consider the center-of-mass energy and forward rapidities associated to the measurements by the LHCb Collaboration. The results considering different unintegrated gluon distributions are presented and compared to data and predictions for proton-nucleus collisions are provided.

hep-ph↗

arXiv2022

$D$-meson production in high energy $pA$ collisions within the QCD color dipole transverse momentum representation

The $D$-meson production is investigated by considering the unintegrated gluon distribution within the dipole approach in the momentum representation. We analyze the $D$-meson spectrum accounting for the effects of nonlinear behavior of the QCD dynamics which can be accordingly addressed in the dipole framework. The unintegrated gluon distribution is obtained by using geometric scaling property and the results are compared to the Glauber-Gribov framework. The absolute transverse momentum spectra and the nuclear modification ratios are investigated. Predictions are compared with the experimental measurements by the ALICE and LHCb Collaborations in $pA$ collisions for different rapidity bins.

hep-ph↗

arXiv2021

Charmed meson production based on dipole transverse momentum representation in high energy hadron-hadron collisions available at the LHC

The production of $D$-mesons in high-energy $pp$ collisions at the LHC kinematic regime is analyzed with the dipole approach in the momentum representation. We present predictions for the $D$-meson differential cross section in terms of the transverse momentum and rapidity distributions taking into account the nonlinear behavior of the QCD dynamics. Comparison between our results and the corresponding experimental measurements reported by the ALICE and LHCb Collaborations in different rapidity bins is performed. We show that the $D$-meson production in the high energy limit can be properly addressed by using the QCD dipole transverse momentum distributions.

hep-ph↗

arXiv2020

A study on the isolated photon production in nuclear collisions at the CERN-LHC energies

An analysis of prompt photon production in high energy nuclear collisions at the LHC energy regime is performed within the parton saturation picture taking into account the updated phenomenological color dipole models. The results are confronted with the measurements made by the ALICE, ATLAS, and CMS experiments in terms of photon transverse momentum at different rapidity bins. As a result, we show that the prompt photon production exhibits distinct scalings in $AA$ events associated to geometrical properties of the collision and can be properly addressed in the color dipole formalism.

hep-ph↗

arXiv2020

The color dipole picture for prompt photon production in $pp$ and $pPb$ collisions at the CERN-LHC

A study on the prompt photon production within the QCD color dipole picture with emphasis in $pp$ and $pA$ collisions at the LHC energy regimes is performed. We present predictions for the differential cross section as a function of photon transverse momentum at different rapidity bins considering updated phenomenological color dipole models, which take into account the QCD gluon saturation physics. The results are directly compared to the recent experimental measurements provided by CMS and ATLAS Collaborations, showing a reasonable agreement in all rapidity bins with no free parameters. Special attention is given to the IPSAT model given its good description of the data in all rapidity bins from low- to high-$p_{T}$ ranges. As a result, a free-parameter approach has succeeded in describing the LHC data for prompt photon production, while new predictions for the 13-TeV data is presented in view of new data to confirm such prospect.

hep-ph↗

arXiv2020

Prompt photon production in high-energy $pA$ collisions at forward rapidity

Prompt photon production in hadronic collisions at the RHIC and the LHC energies is investigated within the QCD color dipole approach. Predictions for the nuclear modification factor in $pA$ collisions are evaluated based on parton saturation framework and the results are compared to the experimental measurements as a function of the photon transverse momentum at different rapidity bins. The reliability of the models is performed with the data from PHENIX, ATLAS, and ALICE Collaborations. Moreover, we show that the observed $x_T$-scaling of prompt photon production in $pp$ and $pA$ collisions can positively be addressed in the QCD color dipole formalism.

hep-ph↗

arXiv2020

Exclusive heavy quark photoproduction in $pp$, $pPb$ and $PbPb$ collisions at the LHC and FCC energies

In this paper we present a comprehensive analysis of the exclusive heavy quark photoproduction in $pp$, $pPb$ and $PbPb$ collisions at LHC and FCC energies using the color dipole formalism and taking into account of nonlinear corrections to the QCD dynamics. We estimate the rapidity distributions and cross sections for the charm and bottom production considering three phenomenological models for the dipole-proton scattering amplitude that are able to describe the $ep$ HERA data. Our results indicate that a future experimental analysis of this process is feasible, which will allow us to improve our understanding of the QCD dynamics.

hep-ph↗

arXiv2019

Single inclusive jet photoproduction at very forward rapidities in $pp$ and $pPb$ collisions at the LHC

The particle production at very forward rapidities is expected to be sensitive to the non-linear effects in the QCD dynamics at high energies. In this paper we present, for the first time, the predictions of the Color Dipole formalism for the single inclusive jet photoproduction in $pp$ and $pPb$ collisions considering the very forward rapidities probed by the CMS-CASTOR calorimeter, which will be characterized by a jet in the rapidity range of $5.2 \le Y \le 6.6$, a rapidity gap in the rapidity range probed by the central CMS detector and one of the incident hadrons remaining intact in the final state. The transverse momentum distributions are estimated considering the more recent phenomenological models for the dipole-proton scattering amplitude, which are based on the Color Glass Condensate formalism and are able to describe the inclusive and exclusive $ep$ HERA data. Our results indicate that a future experimental analysis of this process is, in principle, feasible and useful to constrain the description of the QCD dynamics at high energies.

hep-ph↗

arXiv2018

Investigating the exclusive vector meson photoproduction in nuclear collisions at Run 2 LHC energies

We investigate the theoretical uncertainty on the predictions for the photoproduction of $ρ$ and $J/Ψ$ states in nucleus-nucleus collisions at Run 2 LHC energies using the Color Dipole formalism. The results for rapidity distributions and total cross sections are presented. Moreover, we compare directly the theoretical results to the recent preliminary data from ALICE collaboration on $ρ$ production in $PbPb$ collisions at central rapidity.

hep-ph↗

arXiv2017

Inclusive heavy quark photoproduction in $pp$, $pPb$ and $PbPb$ collisions at Run 2 LHC energies

In this paper we present a comprehensive analysis of the inclusive heavy quark photoproduction in $pp$, $pPb$ and $PbPb$ collisions at Run 2 LHC energies using the Color Dipole formalism. The rapidity distributions and total cross sections for the charm and bottom production are estimated considering the more recent phenomenological models for the dipole - proton scattering amplitude, which are based on the Color Glass Condensate formalism and are able to describe the inclusive and exclusive $ep$ HERA data. Moreover, we present, by the first time, the predictions for the transverse momentum distributions of the $D$ and $B$ mesons produced in the photon -- induced interactions.

hep-ph↗

arXiv2017

Color dipole predictions for the exclusive vector meson photoproduction in $pp/pPb/PbPb$ collisions at Run 2 LHC energies

In this paper we present a comprehensive analysis of exclusive vector meson photoproduction in $pp$, $pPb$ and $PbPb$ collisions at Run 2 LHC energies using the Color Dipole formalism. The rapidity distributions and total cross sections for the $ρ$, $ϕ$, $J/Ψ$, $Ψ(2S)$ and $Υ$ production are estimated considering the more recent phenomenological models for the dipole - proton scattering amplitude, which are based on the Color Glass Condensate formalism and are able to describe the inclusive and exclusive $ep$ HERA data. Moreover, we also discuss the impact of the modelling of the vector meson wave functions on the predictions. The current theoretical uncertainty in the Color Dipole predictions is estimated and a comparison with the experimental results is performed.

hep-ph↗

arXiv2015

On theoretical uncertainty of color dipole phenomenology in the J/Psi and Upsilon photoproduction in pA and AA collisions at the CERN Large Hadron Collider

We investigate the theoretical uncertainty on the predictions for the photoproduction of J/psi and Upsilon states in the proton-nucleus and nucleus-nucleus collisions at the LHC within the color dipole formalism. Predictions for the rapidity distributions are presented and the dependence on the meson wavefunction, heavy quark mass as well as the models for the dipole cross section are analyzed. We compare directly the theoretical results to the recent data from ALICE collaboration on J/psi production in pPb collisions at a centre-of-mass energy per nucleon pair of 5.02 TeV and in PbPb collisions at a centre-of-mass energy per nucleon pair of 2.76 TeV. Predictions are also performed for $Υ$ state in PbPb and pPb and pp collisions at the LHC energies, including the coherent and incoherent contributions.

hep-ph↗

arXiv2015

Light vector meson photoproduction in hadron-hadron and nucleus-nucleus collisions at the energies available at the CERN Large Hadron Collider

In this work we analyse the theoretical uncertainties on the predictions for the photoproduction of light vector mesons in coherent pp, pA and AA collisions at the LHC energies using the color dipole approach. In particular, we present our predictions for the rapidity distribution for rh0 and phi photoproduction and perform an analysis on the uncertainties associated to the choice of vector meson wavefunctionand the phenomenological models for the dipole cross section. Comparison is done with the recent ALICE analysis on coherent production of rho at 2.76 TeV in PbPb collisions.

hep-ph↗

arXiv2014

Diffractive dissociation in proton-nucleus collisions at collider energies

The cross section for the nuclear diffractive dissociation in proton-lead collisions at the LHC is estimated. Based on the current theoretical uncertainties for the single (target) diffactive cross section in hadron-hadron reactions one obtains sigma_SD(5.02 TeV) = 19.67 \pm 5.41 mb and sigma_SD(8.8 TeV) = 18.76 \pm 5.77 mb, respectively. The invariant mass M_X for the reaction pPb -> pX is also analyzed. Discussion is performed on the main theoretical uncertainties associated to the calculations.

hep-ph↗

arXiv2014

Exclusive photoproduction of quarkonium in proton-nucleus collisions at energies available at the CERN Large Hadron Collider

In this work we investigate the coherent photoproduction of psi(1S), psi(2S) and Upsilon (1S) states in the proton-nucleus collisions in the LHC energies. Predictions for the rapidity distributions are presented using the color dipole formalism and including saturation effects that are expected to be relevant at high energies. Calculations are done at the energy 5.02 TeV and also for the next LHC run at 8.8 TeV in proton-lead mode. Discussion is performed on the main theoretical uncertainties associated to the calculations.

hep-ph↗