arXiv subjects

Alberto M. Gago

Publications and source records attributed to Alberto M. Gago.

8 recordsLinked to original sources

arXiv2026

Blazar Boosted Dark Matter in IceCube

We study the sensitivity of IceCube to blazar-boosted dark matter in a fermionic dark matter model with a massive vector mediator coupling to quarks. To this aim, we compute the diffuse flux arising from a sample of 324 blazars with proton spectra inferred from multiwavelength observations, adopting conservative dark matter spike profiles around the central supermassive black holes and consistently accounting for attenuation effects during propagation through the Earth. The dark matter-nucleon scattering cross section is evaluated by including elastic, resonant single pion production, and deep inelastic contributions, with particular emphasis on resonant single-pion production channels in order to smoothly cover the transition between the elastic and deep inelastic regimes. Using IceCube neutrino data, we derive constraints on the parameter space of the model and show that this detection strategy can surpass the sensitivity of conventional direct-detection experiments for dark matter masses below $\sim 1$ GeV. We find that the signal is dominated by deep inelastic scattering and is therefore more sensitive to comparatively heavy mediators, while resonance processes provide a reduction of the event rate, reaching up to about $9\%$ near the experimental threshold. Our results demonstrate that IceCube constitutes a powerful probe of sub-GeV dark matter scenarios through the observation of blazar-boosted dark matter.

hep-ph↗

arXiv2026

Exploring neutrino loss with diffuse astrophysical neutrino fluxes

We study the sensitivity of the diffuse high-energy neutrino flux observed in IceCube to new-physics effects resulting in an exponential flux attenuation along the trajectory, such as invisible neutrino decay or new interactions with the background encountered during propagation. We argue that, even though the sources and production redshifts of these astrophysical neutrinos are unknown, conservative energy-conservation arguments allow to severely constrain neutrino loss in most scenarios beyond the strongest existing bounds. By performing a fit to the High-Energy Starting Events from IceCube, we quantify the bounds and study their variation with the energy dependence of the attenuation, the assumed redshift distribution of the neutrino sources, and whether the attenuation affects neutrinos exclusively or no. We also show that including an energy-dependent attenuation at the level allowed in the fit may impact the determination of the spectral index of the diffuse flux.

hep-ph↗

arXiv2025

TAMBO: A Deep-Valley Neutrino Observatory

Although the field of neutrino astronomy has blossomed in the last decade, physicists have struggled to fully map the high-energy neutrino sky. TAMBO, a mountain-based neutrino observatory, aims to solve that issue -- and find clues of new physics along the way.

astro-ph.HE↗

arXiv2024

Quantum Decoherence Effects: a complete treatment

Physical systems in real life are inextricably linked to their surroundings and never completely separated from them. Truly closed systems do not exist. The phenomenon of decoherence, which is brought about by the interaction with the environment, removes the relative phase of quantum states in superposition and makes them incoherent. In neutrino physics, decoherence, although extensively studied has only been analyzed thus far, exclusively in terms of its dissipative characteristics. While it is true that dissipation, or the exponential suppression, eventually is the main observable effect, the exchange of energy between the medium and the system, is an important factor that has been overlooked up until now. In this work, we introduce this term and analyze its consequences.

hep-ph↗

arXiv2017

Testing FLUKA on neutron activation of Si and Ge at nuclear research reactor using gamma spectroscopy

Samples of two characteristic semiconductor sensor materials, silicon and germanium, have been irradiated with neutrons produced at the RP-10 Nuclear Research Reactor at 4.5 MW. Their radionuclides photon spectra have been measured with high resolution gamma spectroscopy, quantifying four radioisotopes ($^{28}$Al, $^{29}$Al for Si and $^{75}$Ge and $^{77}$Ge for Ge). We have compared the radionuclides production and their emission spectrum data with Monte Carlo simulation results from FLUKA. Thus we have tested FLUKA's low energy neutron library (ENDF/B-VIIR) and decay photon scoring with respect to the activation of these semiconductors. We conclude that FLUKA is capable of predicting relative photon peak amplitudes, with gamma intensities greater than 1%, of produced radionuclides with an average uncertainty of 13%. This work allows us to estimate the corresponding systematic error on neutron activation simulation studies of these sensor materials.

physics.ins-det↗

arXiv2017

Visible neutrino decay in the light of appearance and disappearance long baseline experiments

We investigate the present constraints from MINOS and T2K experiments for the neutrino decay scenario induced by non-diagonal couplings of Majorons to neutrinos. As novelty, on top of the typical invisible decay prescription, we add the contribution of visible decay, where final products can be observed. This new effect depends on the nature of the neutrino - Majoron coupling, which can be of scalar or pseudoscalar type. Using the combination of disappearance data from MINOS and disappearance and appearance data from T2K, for normal ordering, we constrain the decay parameter $α\equiv E\,Γ$ for the heaviest neutrino, where $E$ and $Γ$ are the neutrino energy and width, respectively. We find that when considering visible decay within appearance data, one can improve current neutrino long-baseline constraints up to $α< \mathcal{O}(10^{-5})$ eV$^2$, at 90\% C.L., for both kinds of couplings, which is better by one order of magnitude compared to previous bounds.

hep-ph↗

arXiv2015

Probing the Type I Seesaw Mechanism with Displaced Vertices at the LHC

The observation of Higgs decays into heavy neutrinos would be strong evidence for new physics associated to neutrino masses. In this work we propose a search for such decays within the Type I seesaw model in the few-GeV mass range via displaced vertices. Using 300 fb$^{-1}$ of integrated luminosity, at 13 TeV, we explore the region of parameter space where such decays are measurable. We show that, after imposing pseudorapidity cuts, there still exists a region where the number of events is larger than $\mathcal{O}(10)$. We also find that conventional triggers can greatly limit the sensitivity of our signal, so we display several relevant kinematical distributions which might aid in the optimization of a dedicated trigger selection.

hep-ph↗

arXiv2015

Searching for cavities of various densities in the Earth's crust with a low-energy electron-antineutrino beta-beam

We propose searching for deep underground cavities of different densities in the Earth's crust using a long-baseline electron-antineutrino disappearance experiment, realized through a low-energy beta-beam with highly-enhanced luminosity. We focus on four cases: cavities with densities close to that of water, iron-banded formations, heavier mineral deposits, and regions of abnormal charge accumulation that have been posited to appear prior to the occurrence of an intense earthquake. The sensitivity to identify cavities attains confidence levels higher than $3σ$ and $5σ$ for exposures times of 3 months and 1.5 years, respectively, and cavity densities below 1 g cm$^{-3}$ or above 5 g cm$^{-3}$, with widths greater than 200 km. We reconstruct the cavity density, width, and position, assuming one of them known while keeping the other two free. We obtain large allowed regions that improve as the cavity density differs more from the Earth's mean density. Furthermore, we demonstrate that knowledge of the cavity density is important to obtain O(10%) error on the width. Finally, we introduce an observable to quantify the presence of a cavity by changing the orientation of the electron-antineutrino beam, with which we are able to identify the presence of a cavity at the $2σ$ to $5σ$ C.L.

hep-ph↗