arXiv subjects

André V. Giannini

Publications and source records attributed to André V. Giannini.

10 recordsLinked to original sources

arXiv2026

Photoproduction of $J/Ψ$ in peripheral Oxygen-Oxygen collisions

The photoproduction of $J/Ψ$ in peripheral Oxygen - Oxygen ($OO$) collisions at the Large Hadron Collider (LHC) is investigated considering distinct assumptions for the modeling of the nuclear photon flux, overlap function and dipole - proton scattering amplitude. Predictions for the associated rapidity distributions and total cross - sections are presented. Our results indicate that the experimental study of the photoproduction of $J/Ψ$ in peripheral $OO$ collisions is, in principle, feasible. In addition, they point out that the combination of the results for this final state in $OO$ collisions with those obtained for $PbPb$ collisions will allow us to derive important constraints on the description of photon - induced process at peripheral collisions.

hep-ph↗

arXiv2026

Fully charmed tetraquark production in forward rapidity $pp$ collisions at LHC and FCC energies

In this paper, we investigate the production of a fully charmed tetraquark state $T_{4c}$ in $pp$ collisions at forward rapidities through the fragmentation mechanism considering the Color Glass Condensate (CGC) formalism and the solution of the running coupling Balitsky-Kovchegov (BK) equation. The contributions of gluon - and charm - initiated processes are taken into account, and the impact of an intrinsic charm component in the proton's wave function is estimated. Predictions for the transverse momentum distribution of the $T_{4c}$ state are presented assuming different rapidities, distinct quantum numbers of the state and center-of-mass energies. Our results indicate that the higher cross-section is associated with the production of a tensor state $T_{4c}(2^{++})$, which is dominated by the gluon-initiated process. In contrast, the production of the axial-vector state $T_{4c}(1^{+-})$ is dominated by the charm-initiated process and is very sensitive to the presence (or not) of an intrinsic charm.

hep-ph↗

arXiv2025

Photoproduction of heavy vector mesons in peripheral $PbPb$ collisions at the Large Hadron Collider

A comprehensive analysis of the photoproduction of $J/Ψ$ and $Υ$ mesons in peripheral $PbPb$ collisions at the center - of - mass energies of the Large Hadron Collider (LHC) is performed, considering distinct assumptions for the modeling of the nuclear photon flux, photon - nucleus cross - section, overlap function and dipole - proton scattering amplitude. The comparison of these predictions with the ALICE data is also performed. Our results indicate that a detailed analysis of the production of both mesons will be very useful to improve the description of photon - induced processes in peripheral collisions.

nucl-ex↗

arXiv2025

Nuclear Physics Confronts Relativistic Collisions Of Isobars

High-energy collisions involving the $A=96$ isobars $^{96}$Zr and $^{96}$Ru have been performed in 2018 at Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) as a means to search for the chiral magnetic effect in QCD. This would manifest itself as specific deviations from unity in the ratio of observables taken between $^{96}$Zr+$^{96}$Zr and $^{96}$Ru+$^{96}$Ru collisions. Measurements of such ratios (released at the end of 2021) indeed reveal deviations from unity, but these are primarily caused by the two collided isobars having different radial profiles and intrinsic deformations. To make progress in understanding RHIC data, nuclear physicists across the energy spectrum gathered in Heidelberg in 2022 as part of an EMMI Rapid Reaction Task Force (RRTF) to address the following question. Does the combined effort of low-energy nuclear structure physics and high-energy heavy-ion physics enable us to understand the observations made in isobar collisions at RHIC?

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arXiv2024

Impact of the pre-equilibrium phase for the determination of nuclear geometry in high-energy isobar collisions

Ultrarelativistic isobar collisions have been proposed as a useful tool to investigate nuclear structure. These systems are not created in equilibrium, rather undergo a pre-thermalization stage. In this stage, some of the initial structure information may be lost and additional effects introduced. The objective of this paper is to study this possibility in the extreme case of a "free-streaming" pre-equilibrium stage. We do this by computing estimators for ratios of various measured (or measurable) quantities (elliptic and triangular flows, mean transverse momentum and associated cumulants, correlators between elliptic or triangular flows and mean transverse momentum, symmetric cumulant and two-plane correlator) and study their sensitivity to the duration of the free-streaming stage. We find that the correlators between elliptic or triangular flows and mean transverse momentum, the so-called $ρ_2$ and $ρ_3$, are indeed sensitive to the duration of the free-streaming stage and that the normalized symmetric cumulant, $\varepsilon NSC(2,3)$ might also depend on this duration.

nucl-th↗

arXiv2024

$B$-meson production at forward rapidities in $pp$ collisions at the LHC: Estimating the intrinsic bottom contribution

The production of $B$ mesons at forward rapidities is strongly sensitive to the behavior of the gluon and bottom distribution functions for small and large values of the Bjorken - $x$ variable. In this exploratory study, we estimate the cross - section for the $B^{\pm}$ meson production in the kinematic range probed by the LHCb detector and that will be analyzed by the future Forward Physics Facility (FPF) considering the hybrid formalism, the solution of the running coupling Balitsky - Kovchegov equation and distinct descriptions for the bottom distribution function. We assume an ansatz for the intrinsic bottom component in the proton wave function, and estimate its impact on the transverse momentum, rapidity and Feynman - $x$ distributions. Our results indicate that the presence of an intrinsic bottom strongly modifies the magnitude of the cross - section at ultra - forward rapidities ($y \ge 6$), which implies an enhancement of the $B^{\pm}$ production at the FPF. Possible implications on the prompt neutrino flux at ultra-high energies are also briefly discussed.

hep-ph↗

arXiv2024

$D^0$ meson production in $pp$ collisions at large $Q_s^2$

The impact of the non-linear effects in the QCD dynamics on the observables is directly related to the magnitude of the saturation scale $Q_s$, which is predicted to increase with the energy, rapidity and multiplicity. In this paper, we investigate the $D^0$ meson production in $pp$ collisions at forward rapidities and/or high multiplicities considering the Color Glass Condensate (CGC) formalism and the solutions of the running coupling Balitsky - Kovchegov (BK) equation. The contributions of gluon - and charm - initiated processes are taken into account, and a comparison with the current LHCb data is performed. The impact of an intrinsic charm component in the proton's wave function is also estimated. Predictions for the self-normalized yields of $D^0$ mesons as a function of the multiplicity of coproduced charged hadrons are presented, considering $pp$ collisions at $\sqrt{s} = 13$ TeV and different values of the meson rapidity. A comparison with the predictions for the kaon and isolated photon production is performed. Our results indicate that a future experimental analysis of the $D^0$ meson production at forward rapidities and high multiplicities can be useful to probe the CGC formalism and to disentangle the contribution of initial - and final - state effects.

hep-ph↗

arXiv2024

Isolated photon production in $pp$ collisions at forward rapidities and high multiplicity events

The production of isolated photons in high multiplicity events is investigated considering the Color Glass Condensate (CGC) formalism. The associated cross-section for proton - proton collisions is estimated considering three distinct solutions of the Balitsky - Kovchegov (BK) equation and predictions for the normalized photon yield as a function of the multiplicities of co - produced charged particles are presented. We predict the increasing of the yield with the multiplicity, with the slope being smaller for larger rapidities. As the isolated photon production is not affected by the fragmentation process, a future experimental investigation of this process in current high energy hadronic colliders is ideal to test the treatment of high multiplicity events using the CGC formalism, previously applied only for the production of hadronic final states.

hep-ph↗

arXiv2022

Kaon production in high multiplicity events at the LHC

The production of the $K_S^0$ meson in high multiplicity $pp$ collisions at $\sqrt{s} =$ 13 TeV is investigated considering the hybrid formalism and the solution of the running coupling Balitsky - Kovchegov equation. The associated cross section is estimated and compared with the experimental data for the transverse momentum spectrum. Moreover, we analyze the self-normalized yields of $K_S^0$ mesons as a function of the multiplicity of coproduced charged hadrons and demonstrate that a steep increasing is theoretically predicted. A comparison with the ALICE data is presented considering two distinct solutions of the BK equation.

hep-ph↗

arXiv2022

Pre-hydrodynamic evolution in large and small systems

We extend our previous investigation of the effects of pre-hydrodynamic evolution on final-state observables in heavy-ion collisions to smaller systems. We use a state-of-the-art hybrid model for the numerical simulations with optimal parameters obtained from a previous Bayesian study. By studying p-Pb collisions, we find that the effects due to the assumption of a conformal evolution in the pre-hydrodynamical stage are even more important in small systems. We also show that this effect depends on the time duration of the pre-equilibrium stage, which is further enhanced in small systems. Finally, we show that the recent proposal of a free-streaming with subluminal velocity for the pre-equilibrium stage, thus effectively breaking conformal invariance, can alleviate the contamination of final state observables. Our study further reinforces the need for moving beyond conformal approaches in pre-equilibrium dynamics modeling, especially when extracting transport coefficients from hybrid models in the high-precision era of heavy-ion collisions.

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