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Pedro de la Torre Luque

Publications and source records attributed to Pedro de la Torre Luque.

7 recordsLinked to original sources

Galactic cold clouds constraints on sub-GeV DM and asteroid-mass PBHs

We show that the ionization of molecular and atomic clouds provides a novel probe of dark matter scenarios producing low-energy $e^+e^-$ pairs through annihilation, decay, or Hawking evaporation of primordial black holes. We derive constraints on MeV-scale dark matter with masses between $\sim1$ and $100$ MeV, as well as on primordial black holes in the mass range $10^{14}$--$3\times10^{17}$g. By modeling the propagation of electrons and positrons inside these clouds, we show that uncertainties in charged-particle transport constitute the main limitation of this method. Nevertheless, for the most physically motivated propagation scenarios, the resulting constraints remain competitive with the strongest bounds currently available. We also identify the cloud properties that maximize the sensitivity to dark matter-induced ionization and discuss how larger samples of clouds, together with improved modeling of cosmic-ray ionization and cloud structure, could substantially enhance the reach of this technique. Our results establish molecular and atomic cloud ionization as a promising and complementary probe of sub-GeV dark matter and evaporating primordial black holes.

hep-ph↗

The potential of diffuse Galactic Ridge neutrino measurements to constrain dark matter

We use the latest ANTARES Galactic Ridge neutrino measurements to investigate their implications for indirect dark matter (DM) searches. We consider both annihilating and decaying DM scenarios, spanning a wide range of masses and final states, and systematically compare the resulting neutrino fluxes with the expected astrophysical Galactic diffuse emission. Furthermore, we compare the results for different DM density profiles allowed by the observations, from spike and cuspy to cored profiles. We do so for the WIMP model-independent scenario and explore two more specific models: branons and very heavy sterile neutrinos, where a cold DM candidate arises naturally from the theory. We show the potential neutrino measurements in the Galactic Ridge for DM and make predictions for future neutrino observatories.

astro-ph.HE↗

Galactic Center Neutrinos from Cosmic Ray-Dark Matter Interactions

The IceCube and ANTARES collaborations have recently reported evidence for high-energy neutrinos associated with the Galactic plane and the Galactic Ridge, offering a new pathway to search for dark matter (DM). Deep inelastic scattering of cosmic rays with sub-GeV DM in the Galactic halo produces a distinctive neutrino signature from meson decays. Using detailed Galactic cosmic-ray maps and ANTARES observations, we derive 99% C.L. upper limits on the DM-nucleon cross section that extend down to keV-scale masses. These results establish Galactic neutrino telescopes as a powerful, complementary probe of light DM, with substantial improvements expected from upcoming IceCube-Gen2 and KM3NeT observations.

hep-ph↗

The cosmic-ray positron excess and its imprint in the Galactic gamma-ray sky

We study the origin of the positron excess observed in the local cosmic-ray spectrum at high energies, and relate it to the cosmic rays and gamma-ray emission across the entire Galaxy. In particular, we explore the hypothesis of a single, dominant source accountable for primary electron-positron pairs. Since we are agnostic about the physical nature of the underlying source population, we consider four simple models that are representative of young pulsars, old stars (as a tracer of millisecond pulsars), and annihilating dark matter particles. In the dark matter hypothesis, we consider both a cored and a cuspy model for the halo in the Milky Way. Then, we compare the associated gamma-ray sky maps with Fermi-LAT data. The aim of this work is not to derive constraints or upper limits for the different models considered, but rather to explore the possibility, as a proof of concept, of building a self-consistent model able to explain simultaneously the origin of all cosmic-ray species, including positrons, as well as the Galactic center GeV gamma-ray emission. We find that the emission arising from pulsar wind nebulae is fairly concentrated near the mid plane, and therefore additional cosmic-ray sources must be invoked to explain the emission at the center of the Galaxy. If the local positron excess were mainly due to millisecond pulsars, inverse Compton scattering by the particles injected in the Milky Way bulge would naturally account for a non-negligible fraction of the central gamma-ray emission. The case of annihilating dark matter is very sensitive to the precise shape of the dark matter profile. The results for a standard NFW cuspy profile are above the gamma-ray measurements by as much as a factor of 2 in some regions of the Galaxy, while the results for an isothermal, cored profile are still compatible with the data. However, the cross-sections exceed the current constraints.

astro-ph.HE↗

Cosmic-ray propagation and production of secondary particles in the Galaxy

Cosmic rays are nowadays a crucial tool to study the astrophysics of extreme objects in the Universe, the cosmic environmental plasma (both Galactic and extra-galactic), the physics of nuclear interactions or the properties of elementary particles at very high energies and even cosmological problems such as the dark matter puzzle. In this thesis, the phenomenology on the transport of Galactic cosmic rays is studied in light of the most recent experimental data in the field and new analyses are presented in order to obtain better constraints. Throughout the thesis, secondary particles produced from collisions of cosmic rays with the interstellar gas, such as secondary cosmic ray nuclei (B, Be and Li), antiprotons and gamma rays, are treated in order to adjust and test our models and probe different scenarios, such as possible signatures of dark matter decay or annihilation. A preliminary version of the upcoming DRAGON2 code has been used to perform the propagation computations. With the increasing accuracy of CR data a number of anomalies have appear with respect to the standard paradigm of propagation of charged particles in the Galaxy. In this thesis, we demonstrate that some of these anomalies disappear by taking into account the systematic uncertainties involving these kind of analyses, specially cross sections uncertainties.

astro-ph.HE↗

FLUKA cross sections for cosmic-ray interactions with the DRAGON2 code

Secondary particles produced in spallation reactions of cosmic rays with the interstellar gas provide valuable information that allow us to investigate the injection and transport of charged particles in the Galaxy. A good understanding of the cross sections of production of these particles is crucial to correctly interpret our models, although the existing experimental data is very scarce and uncertain. We have developed a new set of cross sections, both inelastic and inclusive, computed with the {\tt FLUKA} Monte Carlo nuclear code and tested its compatibility with CR data. Inelastic and inclusive cross sections have been compared to the most up-to-date data and parameterisations finding a general good agreement. Then, these cross sections have been implemented in the {\tt DRAGON2} code to characterize the spectra of CR nuclei up to $Z=26$ and the secondary-to-primary ratios of B, Be and Li. Interestingly, we find that the FLUKA cross sections allow us to predict an energy-dependence of the B, Be and Li flux ratios which is compatible with AMS-02 data and to reproduce simultaneously these flux ratios with a scaling lower than $20\%$. Finally, we implement the cross sections of production of gamma rays, calculated with {\tt FLUKA}, in the {\tt Gammasky} code and compute diffuse gamma-ray sky maps and the local HI emissivity spectrum, finding a very good agreement with Fermi Large Area Telescope data.

astro-ph.HE↗

Implications of current nuclear cross sections on secondary cosmic rays with the upcoming DRAGON2 code

Current measurements of cosmic-ray fluxes have reached unprecedented accuracy thanks to the new generation of experiments, and in particular the AMS-02 mission. At the same time, significant progress has been made in the propagation models of galactic cosmic rays. These models include several propagation parameters, which are usually inferred from the ratios of secondary to primary cosmic rays, and which depend on the cross sections describing the collisions among the various species of cosmic-ray nuclei. At present, our knowledge of these cross sections in the energy range where cosmic-ray interactions occur is limited, and this is a source of uncertainties in the predicted fluxes of secondary cosmic-ray nuclei. In this work we study the impact of the cross section uncertainties on the fluxes of light secondary nuclei (Li, Be, B) using a preliminary version of the upcoming {\tt DRAGON2} code. We first present a detailed comparison of the secondary fluxes computed by implementing different parametrizations for the network of spallation cross sections. Then, we propose for the first time the use of secondary-over-secondary cosmic-ray flux ratios as a tool to investigate the consistency of cross sections models and give insight of the overall uncertainties coming from the cross sections parametrizations. We show that the uncertainties inferred from the cross section data are enough to explain the discrepancies in the Be and Li fluxes with respect to the AMS-02 data, with no need of a primary component in their spectra. In addition, we show that the fluxes of B, Be and Li can be simultaneously reproduced by rescaling their cross sections within the experimental uncertainty. Finally, we also revisit the diffusive estimation of the halo size, obtaining good agreement with previous works and a best fit value of $6.8 \pm 1$ kpc from the most updated cross sections parametrizations.

astro-ph.HE↗