Papers by Pedro de la Torre Luque
arXiv (Cornell University), Sep 6, 2023
Galaxy clusters are expected to be both dark matter (DM) reservoirs and storage rooms for the cos... more Galaxy clusters are expected to be both dark matter (DM) reservoirs and storage rooms for the cosmic-ray protons (CRp) that accumulate along the cluster's formation history. Accordingly, they are excellent targets to search for signals of DM annihilation and decay at γ-ray energies and are predicted to be sources of large-scale γ-ray emission due to hadronic interactions in the intracluster medium (ICM). In this paper, we estimate the sensitivity of the Cherenkov Telescope Array (CTA) to detect diffuse γ-ray emission from the Perseus galaxy cluster. We first perform a detailed spatial and spectral modelling of the expected signal for both the DM and the CRp components. For each case, we compute the expected CTA sensitivity accounting for the CTA instrument response functions. The CTA observing strategy of the Perseus cluster is also discussed. In the absence of a diffuse signal (non-detection), CTA should constrain the CRp to thermal energy ratio X 500 within the characteristic radius R 500 down to about X 500 < 3 × 10 −3 , for a spatial CRp distribution that follows the thermal gas and a CRp spectral index α CRp = 2.3. Under the optimistic assumption of a pure hadronic origin of the Perseus radio mini-halo and depending on the assumed magnetic field profile, CTA should measure α CRp down to about ∆α CRp ≃ 0.1 and the CRp spatial distribution with 10% precision, respectively. Regarding DM, CTA should improve the current ground-based γ-ray DM limits from clusters observations on the velocityaveraged annihilation cross-section by a factor of up to ∼ 5, depending on the modelling of DM halo substructure. In the case of decay of DM particles, CTA will explore a new region of the parameter space, reaching models with τ χ > 10 27 s for DM masses above 1 TeV. These constraints will provide unprecedented sensitivity to the physics of both CRp acceleration and transport at cluster scale and to TeV DM particle models, especially in the decay scenario.
Antiproton bounds on dark matter annihilation from a combined analysis using the DRAGON2 code
Journal of Cosmology and Astroparticle Physics, May 1, 2024
arXiv (Cornell University), Jun 17, 2024
We revisit the role of primordial black holes (PBHs) as potential dark matter (DM) candidates, pa... more We revisit the role of primordial black holes (PBHs) as potential dark matter (DM) candidates, particularly focusing on light asteroid-mass PBHs. These PBHs are expected to emit particles through Hawking evaporation that can generate cosmic rays (CRs), eventually producing other secondary radiations through their propagation in the Milky Way, in addition to prompt emissions. Here, we perform a comprehensive analysis of CR signals resulting from PBH evaporation, incorporating the full CR transport to account for reacceleration and diffusion effects within the Milky Way. In particular, we revisit the e ± flux produced by PBHs, using Voyager 1, and study for the first time the diffuse X-ray emission from the up-scattering of Galactic ambient photons due to PBH-produced e ± via the inverse Compton effect using Xmm-Newton data, as well as the morphological information of the diffuse 511 keV line measured by Integral/Spi. In doing so, we provide leading constraints on the fraction of DM that can be in form of PBHs in a conservative way, whilst also testing how different assumptions on spin and mass distributions affect our conclusions.
arXiv (Cornell University), Jun 11, 2024
Several extensions of the Standard Model predict the existence of sub-GeV particles that can be c... more Several extensions of the Standard Model predict the existence of sub-GeV particles that can be copiously produced in the cores of supernovae. A broad family of these particles are dubbed feebly interacting particles (FIPs), which can have masses of up to a few hundreds of MeV. Here, we review the most recent and leading constraints on electrophilic FIPs, describing multimessenger techniques that allow us to probe the full phenomenology of the electron/positron emission produced by these FIPs; from their associated X-ray emission to the production of the 511 keV line. Furthermore, the approach described here is independent of the specific particle model and can be translated to the coupling and other properties of a variety of different particles, such as axion-like particles, sterile neutrinos or dark photons a Speaker
arXiv (Cornell University), May 21, 2024
Recent γ-ray and neutrino observations seem to favor the consideration of nonuniform diffusion of... more Recent γ-ray and neutrino observations seem to favor the consideration of nonuniform diffusion of cosmic rays (CRs) throughout the Galaxy. In this study, we investigate the consequences of spatially-dependent inhomogeneous propagation of CRs on the fluxes of secondary CRs and antiprotons detected at Earth. A comparison is made among different scenarios in search of potential features that may guide us toward favoring one over another in the near future. We also examine both the influence of inhomogeneous propagation in the production of secondary CRs from interactions with the gas, and the effects of this scenario on the local fluxes of antiprotons and light antinuclei produced as final products of dark matter annihilation. Our results indicate that the consideration of an inhomogeneous diffusion model could improve the compatibility of the predicted local antiproton flux with that of B, Be and Li, assuming only secondary origin of these particles. In addition, our model predicts a slightly harder local antiproton spectrum, making it more compatible with the high energy measurements of AMS-02. Finally, no significant changes are expected in the predicted local flux of antiprotons and antinuclei produced from dark matter among the different considered propagation scenarios.
Physical review. D/Physical review. D., May 17, 2024
During galactic Supernova (SN) explosions, a large amount of feebly interacting particles (FIPs) ... more During galactic Supernova (SN) explosions, a large amount of feebly interacting particles (FIPs) may be produced. In this work we analyze electrophilic FIPs with masses in the MeV-range that escape from SN and decay into electron-positron pairs, causing an exotic leptonic injection. This contribution adds up to known components, leading to an unexpected excess of X-ray fluxes generated by inverse-Compton scattering of the injected particles on low-energy photon backgrounds. For the first time in the context of FIPs, we use XMM-Newton X-ray measurements to obtain the strongest and most robust bounds on electrophilic FIPs produced by SN in our Galaxy.
arXiv (Cornell University), Apr 19, 2024
Tentative observations of cosmic-ray antihelium by the AMS-02 collaboration have re-energized the... more Tentative observations of cosmic-ray antihelium by the AMS-02 collaboration have re-energized the quest to use antinuclei to search for physics beyond the standard model. However, our transition to a data-driven era requires more accurate models of the expected astrophysical antinuclei fluxes. We use a state-of-the-art cosmic-ray propagation model, fit to high-precision antiproton and cosmic-ray nuclei (B, Be, Li) data, to constrain the antinuclei flux from both astrophysical and dark matter annihilation models. We show that astrophysical sources are capable of producing O(1) antideuteron events and O(0.1) antihelium-3 events over 15 years of AMS-02 observations. Standard dark matter models could potentially produce higher levels of these antinuclei, but showing a different energy-dependence. Given the uncertainties in these models, dark matter annihilation is still the most promising candidate to explain preliminary AMS-02 results. Meanwhile, any robust detection of antihelium-4 events would require more novel dark matter model building or a new astrophisical production mechanism.
Gamma-ray lines in 15 years of Fermi-LAT data: New constraints on Higgs portal dark matter
Physical review. D/Physical review. D., Feb 1, 2024
arXiv (Cornell University), Jan 17, 2024
Early studies of the AMS-02 antiproton ratio identified a possible excess over the expected astro... more Early studies of the AMS-02 antiproton ratio identified a possible excess over the expected astrophysical background that could be fit by the annihilation of a weakly interacting massive particle (WIMP). However, recent efforts have shown that uncertainties in cosmic-ray propagation, the antiproton production cross-section, and correlated systematic uncertainties in the AMS-02 data, may combine to decrease or eliminate the significance of this feature. We produce an advanced analysis using the DRAGON2 code which, for the first time, simultaneously fits the antiproton ratio along with multiple secondary cosmic-ray flux measurements to constrain astrophysical and nuclear uncertainties. Compared to previous work, our analysis benefits from a combination of: (1) recently released AMS-02 antiproton data, (2) updated nuclear fragmentation cross-section fits, (3) a rigorous Bayesian parameter space scan that constrains cosmic-ray propagation parameters. We find no statistically significant preference for a dark matter signal and set strong constraints on WIMP annihilation to b b, ruling out annihilation at the thermal cross-section for dark matter masses below ∼ 200 GeV. We do find a positive residual that is consistent with previous work, and can be explained by a ∼ 70 GeV WIMP annihilating below the thermal cross-section. However, our default analysis finds this excess to have a local significance of only 2.8σ, which is decreased to 1.8σ when the look-elsewhere effect is taken into account.
arXiv (Cornell University), Dec 7, 2023
We explore the 511 keV emission associated to sub-GeV dark matter (DM) particles that can produce... more We explore the 511 keV emission associated to sub-GeV dark matter (DM) particles that can produce electron-positron pairs and form positronium after thermalizing. We use ∼ 16 yr of SPI data from INTEGRAL to constrain DM properties, considering the full positron propagation and losses, and the free electron density drop away from the Galactic plane. We show that the predicted longitude and latitude profiles vary significantly for different DM masses, unlike previous assumptions, and obtain the strongest limits on sub-GeV DM (from the MeV to a few GeV) so far, excluding crosssections down to ⟨σv⟩ ≲ 10 −32 cm 3 s −1 for m χ ∼ 1 MeV and ⟨σv⟩ ≲ 10 −26 cm 3 s −1 for m χ ∼ 5 GeV and lifetimes up to τ ≳ 10 29 s (m χ ∼ 1 MeV) and τ ≳ 10 27 s (m χ ∼ 5 GeV) for the typical Navarro-Frenk-White DM profile. Our derived limits are robust within a factor of a few due to systematic uncertainties.
Prospects for a survey of the Galactic plane with the Cherenkov Telescope Array
We study sub-GeV dark matter (DM) particles that may annihilate or decay into 1 SM particles prod... more We study sub-GeV dark matter (DM) particles that may annihilate or decay into 1 SM particles producing an exotic injection component in the Milky Way that leaves 2 an imprint in both photon and cosmic ray (CR) fluxes. Specifically, the DM particles 3 may annihilate or decay into e + e -, µ + µ -or π + π -and may radiate photons through 4 their e ± products. The resulting e ± products can be directly observed in probes such 5 as Voyager 1. Alternatively, the e ± products may produce bremsstrahlung radiation 6 and upscatter the low-energy galactic photon fields via the inverse Compton process 7 generating a broad emission from X-ray to γ-ray energies observable in experiments 8 such as Xmm-Newton. We find that we get a significant improvement in the DM 9 annihilation and decay constraints from Xmm-Newton (excluding thermally averaged 10 cross sections of 10 -31 cm 3 s -1 ≲ ⟨σv⟩ ≲ 10 -26 cm 3 s -1 and decay lifetimes of 10 26 s ≲ 11 τ ≲ 10 28 s respectively) by including best fit CR propagation and diffusion parameters. 12 This yields the strongest astrophysical constraints for this mass range of DM of 1 MeV 13 to a few GeV and even surpasses cosmological bounds across a wide range of masses as 14 well.
HAL (Le Centre pour la Communication Scientifique Directe), Aug 9, 2023
During galactic Supernova (SN) explosions, a large amount of feebly interacting particles (FIPs) ... more During galactic Supernova (SN) explosions, a large amount of feebly interacting particles (FIPs) may be produced. In this work we analyze electrophilic FIPs with masses in the MeV-range that escape from SN and decay into electron-positron pairs, causing an exotic leptonic injection. This contribution adds up to known components, leading to an unexpected excess of X-ray fluxes generated by inverse-Compton scattering of the injected particles on low-energy photon backgrounds. For the first time in the context of FIPs, we use XMM-Newton X-ray measurements to obtain the strongest and most robust bounds on electrophilic FIPs produced by SN in our Galaxy.
HAL (Le Centre pour la Communication Scientifique Directe), Aug 9, 2023
We study MeV-scale electrophilic Feebly Interacting Particles (FIPs), that may be abundantly prod... more We study MeV-scale electrophilic Feebly Interacting Particles (FIPs), that may be abundantly produced in Supernova (SN) explosions, escape the star and decay into electrons and positrons. This exotic injection of leptons in the Milky Way leaves an imprint in both photon and cosmic-ray fluxes. Specifically, positrons lose energy and annihilate almost at rest with background electrons, producing photons with 511 keV energy. In addition, electrons and positrons radiate photons through bremsstrahlung emission and upscatter the low-energy galactic photon fields via the inverse Compton process generating a broad emission from X-ray to γ-ray energies. Finally, electrons and positrons are directly observable in cosmic ray experiments. In order to describe the FIP-induced lepton injection in full generality, we use a model independent parametrization which can be applied to a host of FIPs such as axion-like particles, dark photons and sterile neutrinos. Theoretical predictions are compared to experimental data to robustly constrain FIP-electron interactions with an innovative multimessenger analysis.
Antinuclei with the DRAGON2 code and AMS-02 preliminary observation
Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)
Physical Review D
Standard Model extensions with a strongly coupled dark sector can induce high-multiplicity states... more Standard Model extensions with a strongly coupled dark sector can induce high-multiplicity states of soft quarks. Such final states trigger extremely efficient antinucleus formation. We show that dark matter annihilation or decay into a strongly coupled sector can dramatically enhance the cosmic-ray antinuclei flux-by six orders of magnitude in the case of 4 He. In this work, we argue that the tentative 3 He and 4 He events reported by the AMS-02 Collaboration could be the first sign of a strongly coupled dark sector observed in nature.
The European Physical Journal C
The elusive nature of Dark Matter (DM) remains a mystery far from being solved. A vast effort is ... more The elusive nature of Dark Matter (DM) remains a mystery far from being solved. A vast effort is dedicated to search for signatures of feeble DM interactions with Standard Model particles. In this work, we explore the signatures of axion DM boosted by interactions with Supernova neutrinos: Neutrino-Boosted Axion DM ($$\nu $$ ν BADM). We focus on $$\nu $$ ν BADM converting into photons in the Galactic magnetic field, generating a peculiar gamma-ray flux. This signal falls in the poorly explored MeV energy range, that will be probed by next generation gamma-ray missions. Once more, astrophysical searches might act as a probe of fundamental physics, unveiling the nature and properties of DM.
The Galactic diffuse gamma-ray emission meets the PeV frontier
Proceedings of 7th Heidelberg International Symposium on High-Energy Gamma-Ray Astronomy — PoS(Gamma2022), Apr 19, 2023
Proceedings of 27th European Cosmic Ray Symposium — PoS(ECRS), Feb 15, 2023
Current measurements of cosmic-ray fluxes have reached unprecedented accuracy thanks to the new g... more 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 with the interstellar medium (spallation cross sections). The current spallation cross sections are based on set of parameterizations mixing (few) data points and simulation predictions for those channels with no measurements. In this work, we present new sets of spallation cross sections of cosmic-ray interactions in the Galaxy, both inelastic and inclusive, computed with FLUKA simulation code that has been extensively tested against data. Furthermore, these cross sections have been implemented in the DRAGON2 code to characterize the spectra of CR nuclei up to Z=26 (Iron) and study the main propagation parameters predicted from the spectra of secondary CRs such as B, Be and Li. We discuss these results and their implications.
Proceedings of 27th European Cosmic Ray Symposium — PoS(ECRS)
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Papers by Pedro de la Torre Luque