arXiv subjects

Victor P. Goncalves

Publications and source records attributed to Victor P. Goncalves.

At least 37 records · Page 2Linked to original sources

arXiv2025

Probing a $Z'$ gauge boson via neutrino trident scattering in the Forward Physics Facility at the LHC and FCC

The study of neutrino physics at the Large Hadron Collider is already a reality, and a broad neutrino physics program is expected to be developed in forthcoming years at the Forward Physics Facility (FPF). In particular, the neutrino trident scattering process, which is a rare Standard Model process, is expected to be observed for the first time with a statistical significance of $5σ$ using the FASER$ν$2 detector. Moreover, similar studies are expected to be performed in the proposed Future Circular Collider (FCC). Such perspectives motivate the investigation of the impact of New Physics on the predictions for the corresponding number of events. In this letter, we consider the $L_μ- L_τ$ model, which predicts an additional massive neutral gauge boson, $Z'$, that couples to neutrino and charged leptons of the second and third families, and estimate the production of a dimuon system in the neutrino trident scattering at the FASER$ν$2 assuming different models for the incoming neutrino flux at the LHC and FCC energies. We derive the associated sensitivity and demonstrate that the FPF@LHC is not able to improve the current bounds on the $L_μ- L_τ$ model, while a future measurement of the dimuons produced in neutrino trident events in the FPF@FCC will extend the coverage of the parameter space in comparison to previous experiments.

hep-ph↗

arXiv2025

Probing a low-mass $Z^{\prime}$ gauge boson at IceCube and prospects for IceCube-Gen2

In this work, we investigate the impact of the $L_μ- L_τ$ model, which predicts a new massive gauge boson, $Z'$, on astrophysical neutrino events at the IceCube Observatory. This new gauge boson couples with leptons from the second and third families, and would break the power law of the astrophysical neutrino flux due to the interaction of this flux with the cosmic neutrino background. We derive the sensitivity of the IceCube to this model considering the HESE data from 12 years of observation by assuming different assumptions for the redshift distributions of astrophysical neutrino sources, mass ordering, and sum of neutrino masses. Our results indicate that the current IceCube data is able to probe small coupling and masses of the order of some few MeV, with the covered parameter space being larger if a distribution of neutrino sources is described by the star formation rate model. In addition, we demonstrate that the IceCube-Gen2 will cover a large region of the parameter space and will allow us to improve our understanding of the $L_μ- L_τ$ model.

hep-ph↗

arXiv2025

Associated jet + electroweak gauge boson production in hadronic collisions at forward rapidities in the color-dipole $S$-matrix framework

The cross-section for the associated production of a jet with an electroweak gauge boson ($G = W^{\pm}, Z^0, γ$) at forward rapidities in $pp$ and $pA$ collisions is derived within the color - dipole $S$ - matrix framework. We present the full expressions for the differential cross-section of the $q p \rightarrow G q X$ process in the transverse momentum space, considering the longitudinal and transverse polarizations of the gauge boson. We demonstrate that the final formulae can be expressed in terms of the unintegrated gluon distribution and reproduce previous results for the associated jet + $γ$ and jet + $Z^0$ production, derived using other frameworks. Moreover, we derive the back - to - back correlation limit of the spectra and show that it can be expressed in terms of the unpolarized and linearly polarized transverse momentum gluon distributions. Our results improve the description of the inclusive jet plus color neutral particle production at forward rapidities, not far from the proton fragmentation region, in $pp$ or $pA$ collisions, and are the main ingredient to study the impact of nonlinear QCD effects in two - particle correlations.

hep-ph↗

arXiv2025

Estimating the BFKL effects on the vector meson + jet production in photon - induced interactions at the LHC

The associated vector meson + jet production in photon - induced interactions at the LHC is investigated and predictions for the cross - sections are derived considering the NLO corrections to the BFKL kernel. We explore the possibility that in a near future the FOCAL detector could be used to measure the jet at forward rapidities, with the associated meson being measured by a central or forward detector, and estimate the rapidity distributions for the $ρ$ + jet and $J/Ψ$ + jet photoproduction in $pp$, $Pbp$ and $PbPb$ collisions. We demonstrate that the associated cross-sections are non - negligible and that a future experimental analysis can be useful to constrain the description of the BFKL kernel and improve our understanding of the QCD dynamics.

hep-ph↗

arXiv2025

Probing axion-like particles through the gamma-ray production from cosmic-ray scattering in the Milky Way dark matter halo

Axion-like particles (ALP) are promising candidates to comprise all the dark matter in the universe. We investigate the ALP couplings to photons and electrons via astrophysical measurements through the search for very-high-energy gamma rays arising from high-energy cosmic-ray scattering off ALP populating the halo of the Milky Way. We show that gamma-ray signals from ALP couplings to photons and electrons via inverse Primakoff and Compton processes respectively, can be probed by very-high-energy ($\gtrsim$100 GeV) gamma-ray ground-based observatories, providing an alternative and complementary avenue to probe ALP couplings in the eV mass range. Sensitivities of current and near-future ground-based gamma-ray observatories improves upon one order of magnitude the current constraints from gamma-ray satellite experiments for the ALP-photon couplings in the region of masses below 10$^{-9}$ GeV. Their sensitivities reached on the ALP-electron couplings allow probing masses below 10$^{-8}$ GeV, which are lower than the masses probed in gamma-ray satellite experiments.

astro-ph.HE↗

arXiv2024

Probing Lorentz violating effects on the exclusive $e^+e^-$ production in ultraperipheral heavy-ion collisions

The impact of Lorentz violating (LV) terms on the exclusive $e^+e^-$ production in ultraperipheral heavy-ion collisions at the Large Hadron Collider (LHC) is investigated, considering vectorial and axial couplings. Results for the differential and total cross-sections are presented, and the sensitivity to a time-like coupling is estimated. Our results indicate that this process can improve the current upper bounds on the LV terms.

hep-ph↗

arXiv2024

Tau polarization effects in $ν_τ/ \barν_τ$-tungsten interactions at the LHC energies

Recent studies have demonstrated that the tau produced in charged current neutrino deeply inelastic interactions at the GeV -- TeV neutrino energy range is not fully polarized. In this paper we investigate the impact of the tau polarization on the pions generated in its decay. In particular, we consider tau neutrino - tungsten interactions at the LHC energies and estimate the associated pion momentum, energy and angular distributions. The contribution of the $F_5$ is also investigated. Our results indicate that the pion properties are sensitive to the tau polarization state as well as to the magnitude of $F_5$.

hep-ph↗

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

Probing the spatial distribution of gluons within the proton in the coherent vector meson production at large $|t|$

The coherent production of vector mesons in photon - hadron interactions is considered one of the most promising observables to probe the QCD dynamics at high energies and the transverse spatial distribution of the gluons in the hadron wave function. In this paper, we perform an exploratory study about the dependence of the transverse momentum distributions, $dσ/dt$, on the model assumed for the proton density profile. We consider a set of non-Gaussian profiles and include them in the forward dipole - proton scattering amplitude associated with the IP-sat model. We demonstrate that the predictions for $dσ/dt$ are similar in the HERA kinematical range, but are very distinct for values of $t$ that will be probed in future colliders. In particular, the presence of diffractive dips in the $t$-distributions associated with the production of $J/Ψ$ and $ρ$ mesons is strongly dependent on the model assumed for the density profile. Similar conclusions are also derived when the non-linear effects on the dipole - target interaction are disregarded. Our results indicate that a future study of the coherent vector meson production at large - $t$ will be useful to constrain the spatial distribution of gluons within the proton.

hep-ph↗

arXiv2024

Particle production by $γ$-$γ$ interactions in future electron-ion colliders

The particle production in photon-photon ($γγ$) interactions present in electron-ion collisions is investigated. We present calculations for the total cross sections and event rates related to the production of light mesons [$η, η^\prime, f_0$ and $f_2$], charmonium [$η_c$ and $χ_c$] and charmoniumlike [$X(3915), X(3940), X(4140)$ and $X(6900)$] states, considering the EIC, EicC, LHeC and FCC-eh energies. Our predictions demonstrate that experimental studies of these processes are feasible and useful to constrain the properties of light mesons and quarkonium states and shed some light on the configuration of the considered charmoniumlike states.

hep-ph↗

arXiv2024

Track signals at IceCube from subleading channels

Tracks events at the IceCube Observatory are characterized by an energetic muon crossing several kilometers before decaying. Such muons are dominantly produced in charged current (CC) muon neutrino - hadron interactions. However, muons are also produced through the $W$ - boson production and in the decay of tau leptons and heavy mesons created in neutral and charged current interactions induced by all neutrino flavors. In this paper, we investigate the contribution of these subleading channels to events characterized as tracks at the IceCube. Our results indicate that these channels correspond to a non - negligible fraction of the HESE track events. In addition, we show that its contributions are concentrated in muons that are less energetic than those arising from muonic neutrino CC interactions for the same visible energies of the process. Finally, we investigate the impact of these additional channels on the description of the astrophysical neutrino flux, and we find that the inclusion of these subleading processes are important in determining the parameters of the astrophysical neutrino flux.

hep-ph↗

arXiv2024

Neutrino trident scattering at the LHC energy regime

The neutrino trident scattering process in neutrino - tungsten interactions at the LHC energy regime is investigated, and the cross-sections for different leptonic final states in coherent and incoherent interactions are estimated. Furthermore, the associated number of eventsat FASER$ν$2 detector is estimated considering different predictions for the flux of incident neutrinos on the detector, based on distinct hadronic models for the particle production in $pp$ collisions at ultra-forward rapidities. Our results indicate that the observation of the neutrino trident process is, in principle, feasible at the Forward Physics Facility.

hep-ph↗

arXiv2024

Sensitivity to sub-GeV dark matter from cosmic-ray scattering with very-high-energy gamma-ray observatories

Huge efforts have been deployed to detect dark matter (DM) in the GeV-TeV mass range involving various detection techniques, and led to strong constraints in the available parameter space. We compute here the sensitivity to sub-GeV DM that can be probed from the inevitable cosmic-ray scattering onto DM particles populating the Milky Way halo. Inelastic scattering of energetic cosmic rays off DM would produce high-energy gamma rays in the final state, providing a new avenue to probe the poorly-constrained so far sub-GeV dark matter mass range. In this work we derive sensitivity forecasts for the inelastic cosmic-ray proton - DM cross section for current and future very-high-energy gamma-ray observatories such as H.E.S.S., LHAASO, CTA and SWGO in the 100 eV to 100 MeV mass range. These inelastic cross section constraints are converted to the elastic proton - DM cross section to highlight further complementarity with cosmological, collider and direct detection searches. The sensitivity computed at 95\% confidence level on the elastic cross section reaches $\sim$2$\times$ 10$^{-32}$ cm$^2$ for a 100 keV DM mass for H.E.S.S.-like and $\sim$7$\times$ 10$^{-34}$ cm$^2$ for a $\sim$1 keV DM mass for LHAASO. The sensitivity prospects for CTA and a strawman SWGO model reach $\sim$6$\times$ 10$^{-34}$ cm$^2$ and $\sim$4$\times$ 10$^{-35}$ cm$^2$, for DM masses of 10 keV and 1 keV, respectively. The sensitivity reach of the gamma-ray observatories considered here enables to probe an uncharted region of the DM mass - cross section parameter space.

hep-ph↗

arXiv2024

The asymmetric intrinsic charm in the nucleon and its implications for the $D^{0}$ production in the LHCb $p\!+\!\!^{20}\!N\!e$ fixed-target experiment

Recent results indicate that charm quarks are intrinsic components of the proton wave function, and that the charm and anticharm distributions for a given value of the Bjorken - $x$ variable can be different. In this paper, we will investigate the impact of this asymmetric intrinsic charm on the production of $D^0$ and ${\bar D}^0$ mesons for fixed target $p \!+ ^{20}\!\!Ne$ collisions at the LHCb. In our calculations, we include the contribution of the gluon-gluon fusion, gluon - charm and recombination processes and assume distinct models for the treatment of the intrinsic charm component. We demonstrate that the presence of an intrinsic charm improves the description of the current data for the rapidity and transverse momentum distributions of $D$ mesons. However, such models are not able to describe the LHCb data for the $D^0$-${\bar D}^0$ asymmetry at large transverse momentum, which point out that the description of the intrinsic charm needs to be improved and/or new effects should be taken into account in the production of heavy mesons at forward rapidities in fixed - target collisions.

hep-ph↗

arXiv2024

Tau polarization in neutrino-nucleus interactions at the LHC energy range

Considering that the study of neutrino-nucleus interactions with incident neutrino energy ranges in the GeV-TeV range is feasible at the Large Hadron Collider, we investigate in this paper the degree of polarization ${\cal{P}}$ of the (anti) tau lepton produced in (anti) tau neutrino - tungsten interactions. We estimate the differential cross-sections and the longitudinal and transverse components of the tau lepton polarization as a function of the tau lepton energy and distinct values of the scattering angle, assuming different values for the energy of the incoming (anti) tau neutrino. Different models for the treatment of the nuclear effects in the parton distribution functions are assumed as input in the calculations. Our results indicate that $ {\cal{P}} < 1$ for the neutrino energies reached at the LHC and are almost insensitive to the nuclear effects.

hep-ph↗

arXiv2024

Production of electroweak gauge bosons at forward rapidities in the color - dipole $S$ - matrix framework

The cross-section for the production of an electroweak gauge boson ($G = W^{\pm}, Z^0, γ$) at forward rapidities in $pp$ collisions is derived within the color - dipole $S$ - matrix framework. We present the full expressions for the differential cross-section of the $q p \rightarrow G X$ process in the impact parameter and transverse momentum spaces, considering the longitudinal and transverse polarizations of the gauge boson. The particular cases associated with the Drell - Yan process and real photon production are discussed. We demonstrate that the final formulae are expressed in terms of the dipole - proton cross-section or the unintegrated gluon distribution, and can be used to estimate the impact of the saturation effects in the gauge boson production at the LHC and future colliders.

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

Photoproduction of QED bound states in future electron-ion colliders

In this work we perform an exploratory study of the photoproduction of singlet QED bound states $(l^-l^+)_S$ in electron - ion collisions at the EicC, EIC and LHeC energies. The total cross - sections, event rates per year and rapidity distributions associated with the parapositronium, paramuonium and paratauonium production are estimated. Moreover, we consider the decay of these states in a two - photon system and implement kinematical cuts on the rapidities and energies of the photons in the final state. We demonstrate the paramuonium can, in principle, be observed for the first time in all these colliders and that the EIC is a potential collider to discover the paratauonium state.

hep-ph↗