arXiv subjects

Marco Cirelli

Publications and source records attributed to Marco Cirelli.

At least 19 recordsLinked to original sources

arXiv2026

Direct and Indirect searches for DM-electron interactions in sub-GeV DM models

We analyze the complementarity between direct detection (DD) and indirect detection (ID) searches of sub-GeV dark matter (DM) in the context of two realistic models: the vector-portal (dark photon) and scalar-portal (higgs-portal) models. For DD we focus on the latest constraints on the DM-electron scattering from the present DAMIC-M experiment as well as its future projection. For ID we consider several existing X-rays/gamma-rays and cosmic-ray ($e^\pm$) observations as well as the upcoming MeV telescope COSI to obtain the corresponding bounds and projections on the DM annihilation rate, which are then translated in terms of the DM-electron scattering cross-section and compared with the DD bounds/projections. We properly take into account astrophysical and galactic propagation uncertainties. We find that the complementarity between DAMIC-M and ID works best for the vector-portal model, especially for the case where the vector mediator is heavier than the DM particle: in this case, the present DAMIC-M bound becomes comparable to (or better than, for some astrophysical configurations) the combined ID limit for $3\,{\rm MeV} \lesssim m_{\rm DM} \lesssim 20\,{\rm MeV}$. For other cases and mass ranges, the ID is in general more constraining and can also, for some mass ranges, constrain the parameter space below the neutrino floor, which is inaccessible to DD experiments.

hep-ph↗

arXiv2026

Refined anti-proton and anti-deuteron fluxes from weak-scale Dark Matter

We provide the cosmic-ray (CR) fluxes of antiprotons and antideuterons produced by the Galactic annihilation or decay of weak-scale dark matter (DM) particles of masses in the range from a few GeV to 100 TeV. We estimate these fluxes based on the updated models for the propagation of charged particles in the Galaxy and using the improved $\bar{p}$ and $\bar{d}$ spectra provided by $\texttt{CosmiXs}$. For the updated propagation models we consider the MIN/MED/MAX sets under the new SLIM/BIG/QUAINT schemes. We treat the Galactic propagation in a semi-analytic way including different possible effects such as spatial diffusion, energy-losses, convection and diffusive reacceleration. For the DM distribution in the Galactic halo we consider NFW, Einasto and Burkert profiles with the most updated parameters. Moreover, we also incorporate the latest models for the inelastic cross-sections of $\bar{p}$ and $\bar{d}$ based on ALICE data. We validate our calculations with those available in the literature or those obtained from other publicly available numerical packages. We compare the CR fluxes obtained in this work with those provided previously by $\texttt{PPPC4DMID}$ which were based on old propagation scenarios. We find that the CR fluxes obtained here with the new propagation models are much more robust (compared to the older ones) under the variation MIN - MAX. We also discuss the impact of this in the improvement of the discovery potential of a possible DM signal in the light of the present and upcoming CR observations. We provide all our results for the DM-induced interstellar CR fluxes in a tabulated format (for the kinetic energy range 0.1 GeV - 100 TeV) in the $\texttt{GitHub}$ repository of the newly created $\texttt{CosmiXsPPPC}$ project. The results are ready to be used for studies related to DM indirect searches.

astro-ph.HE↗

arXiv2025

Indirect searches for realistic sub-GeV Dark Matter models

Indirect searches for Dark Matter (DM) particles with mass in the MeV -- GeV scale have received significant attention lately. Pair-annihilations of such DM particles in the Galaxy can give rise to (at the same time) MeV to GeV $\gamma$-rays via prompt emission, sub-GeV $e^\pm$ in cosmic-rays, as well as a broad photon spectrum ranging from $X$-rays to soft $\gamma$-rays, produced by the DM induced $e^\pm$ via inverse Compton scattering, bremsstrahlung and in-flight annihilation processes (collectively called `secondary emissions'). We focus on two representative realistic sub-GeV DM models, namely, the vector-portal kinetic-mixing model and the higgs-portal model, and perform a detailed study of the indirect detection constraints from existing $X$-rays, $\gamma$-rays and cosmic-ray observations, based on all of the above-mentioned signals. We also estimate the future prospects from the upcoming MeV photon telescope COSI, including all possible types of prompt and secondary emission signals. We compare our results with the constraints and (or) projections from cosmological and terrestrial observations. We find that, for both the sub-GeV DM models, the current observations constrain the annihilation cross-section at the level of $\langle \sigma v \rangle \lesssim 10^{-27} {\rm cm}^3/{\rm s}$, or lower for some specific mass ranges or under optimistic assumptions. Moreover, new unconstrained DM parameter space can be probed at the upcoming instruments like COSI, thanks to the inclusion of secondary photons which in many cases provide the dominant signal.

hep-ph↗

arXiv2025

Enhancing European Cooperation in the Search for Dark Matter

The search for dark matter is an exciting topic that is pursued in different communities over a wide range of masses and using a variety of experimental approaches. The result is a strongly correlated matrix of activities across Europe and beyond, both on the experimental and the theoretical side. We suggest to encourage and foster the collaboration of the involved institutions on technical, scientific and organisational level, in order to realise the synergies that are required to increase the impact of dark matter research and to cope with the increasing experiment sizes. The suggested network -- loosely titled "DMInfraNet" -- could be realised as a new initiative of the European strategy or be based on existing structures like iDMEu or DRD. The network can also serve as a nucleus for future joint funding proposals.

hep-ex↗

arXiv2025

Prospects of future MeV telescopes in probing weak-scale Dark Matter

Galactic weak-scale Dark Matter (DM) particles annihilating into lepton-rich channels not only produce gamma-rays via prompt radiation but also generate abundant energetic electrons and positrons, which subsequently emit through bremsstrahlung or inverse Compton scattering (collectively called `secondary-radiation photons'). While the prompt gamma-rays concentrate at high-energy, the secondary emission falls in the MeV range, which a number of upcoming experiments (AMEGO, E-ASTROGAM, MAST...) will probe. We investigate the sensitivity of these future telescopes for weak-scale DM, focusing for definiteness on observations of the galactic center. We find that they have the potential of probing a wide region of the DM parameter space which is currently unconstrained. Namely, in rather optimistic configurations, future MeV telescopes could probe thermally-produced DM with a mass up to the TeV range, or GeV DM with an annihilation cross section 2 to 3 orders of magnitude smaller than the current bounds, precisely thanks to the significant leverage provided by their sensitivity to secondary emissions. We comment on astrophysical and methodological uncertainties, and compare with the reach of high-energy gamma ray experiments.

hep-ph↗

arXiv2024

Dark Matter

We review observational, experimental and theoretical results related to Dark Matter.

hep-ph↗

arXiv2023

iDMEu: An initiative for Dark Matter in Europe and beyond

We introduce the initiative for Dark Matter in Europe and beyond (iDMEu), a collective effort by a group of particle and astroparticle physicists to set up an online resource meta-repository, a common discussion platform and a series of meetings on everything concerning Dark Matter. This document serves as a status report as well as a citable item concerning iDMEu.

hep-ph↗

arXiv2023

Putting all the X in one basket: Updated X-ray constraints on sub-GeV Dark Matter

Sub-GeV dark matter particles can annihilate or decay producing e^\pm pairs which upscatter the low-energy photon fields in the Galaxy and generate an X-ray emission (via the Inverse Compton effect). Using X-ray data from XMM-Newton, INTEGRAL, NuSTAR and Suzaku, we derive new constraints on this class of dark matter (DM). For annihilating DM, they are significant for m_DM > 100 MeV, and dominant if DM is p-wave annihilating. For decaying DM, they are the most stringent to date in the range m_DM ~400 MeV - 3 GeV$.

hep-ph↗

arXiv2022

Integral X-ray constraints on sub-GeV Dark Matter

Light Dark Matter (DM), defined here as having a mass between 1 MeV and about 1 GeV, is an interesting possibility both theoretically and phenomenologically, at one of the frontiers of current progress in the field of DM searches. Its indirect detection via gamma-rays is challenged by the scarcity of experiments in the MeV-GeV region. We look therefore at lower-energy X-ray data from the Integral telescope, and compare them with the predicted DM flux. We derive bounds which are competitive with existing ones from other techniques. Crucially, we include the contribution from inverse Compton scattering on galactic radiation fields and the CMB, which leads to much stronger constraints than in previous studies for DM masses above 20 MeV.

hep-ph↗

arXiv2022

AMS-02 antiprotons and dark matter: Trimmed hints and robust bounds

Based on 4 yr AMS-02 antiproton data, we present bounds on the dark matter (DM) annihilation cross section vs. mass for some representative final state channels. We use recent cosmic-ray propagation models, a realistic treatment of experimental and theoretical errors, and an updated calculation of input antiproton spectra based on a recent release of the PYTHIA code. We find that reported hints of a DM signal are statistically insignificant; an adequate treatment of errors is crucial for credible conclusions. Antiproton bounds on DM annihilation are among the most stringent ones, probing thermal DM up to the TeV scale. The dependence of the bounds upon propagation models and the DM halo profile is also quantified. A preliminary estimate reaches similar conclusions when applied to the 7 years AMS-02 dataset, but also suggests extra caution as for possible future claims of DM excesses.

hep-ph↗

arXiv2022

The Large High Altitude Air Shower Observatory (LHAASO) Science Book (2021 Edition)

Since the science white paper of the Large High Altitude Air Shower Observatory (LHAASO) published on arXiv in 2019 [e-Print: 1905.02773 (astro-ph.HE)], LHAASO has completed the transition from a project to an operational gamma-ray astronomical observatory LHAASO is a new generation multi-component facility located in Daocheng, Sichuan province of China, at an altitude of 4410 meters. It aims at measuring with unprecedented sensitivity the spectrum, composition, and anisotropy of cosmic rays in the energy range between 10$^{12}$ and 10$^{18}$~eV, and acting simultaneously as a wide aperture (one stereoradiant) continuously operating gamma-ray telescope in the energy range between 10$^{11}$ and $10^{15}$~eV with the designed sensitivity of 1.3\% of the Crab Unit (CU) above 100 TeV. LHAASO's capability of measuring simultaneously different shower components (electrons, muons, and Cherenkov/fluorescence light), will allow it to investigate the origin, acceleration, and propagation of CR through measurement of the energy spectrum, elemental composition, and anisotropy with unprecedented resolution. The remarkable sensitivity of LHAASO will play a key role in CR physics and gamma-ray astronomy for a general and comprehensive exploration of the high energy universe and will allow important studies of fundamental physics (such as indirect dark matter search, Lorentz invariance violation, quantum gravity) and solar and heliospheric physics. The LHAASO Collaboration organized an editorial working group and finished all editorial work of this science book, to summarize the instrumental features and outline the prospects of scientific researches with the LHAASO experiment.

astro-ph.HE↗

arXiv2021

New minimal, median, and maximal propagation models for dark matter searches with Galactic cosmic rays

Galactic charged cosmic rays (notably electrons, positrons, antiprotons and light antinuclei) are powerful probes of dark matter annihilation or decay, in particular for candidates heavier than a few MeV or tiny evaporating primordial black holes. Recent measurements by PAMELA, AMS-02, or VOYAGER on positrons and antiprotons already translate into constraints on several models over a large mass range. However, these constraints depend on Galactic transport models, in particular the diffusive halo size, subject to theoretical and statistical uncertainties. We update the so-called MIN-MED-MAX benchmark transport parameters that yield generic minimal, median and maximal dark-matter induced fluxes; this reduces the uncertainties on fluxes by a factor of about 2 for positrons and 6 for antiprotons, with respect to their former version. We also provide handy fitting formulae for the associated predicted secondary antiproton and positron background fluxes. Finally, for more refined analyses, we provide the full details of the model parameters and covariance matrices of uncertainties.

astro-ph.HE↗

arXiv2019

Homeopathic Dark Matter, or how diluted heavy substances produce high energy cosmic rays

We point out that current and planned telescopes have the potential of probing annihilating Dark Matter (DM) with a mass of O(100) TeV and beyond. As a target for such searches, we propose models where DM annihilates into lighter mediators, themselves decaying into Standard Model (SM) particles. These models allow to reliably compute the energy spectra of the SM final states, and to naturally evade the unitarity bound on the DM mass. Indeed, long-lived mediators may cause an early matter-dominated phase in the evolution of the Universe and, upon decaying, dilute the density of preexisting relics thus allowing for very large DM masses. We compute this dilution in detail and provide results in a ready-to-use form. Considering for concreteness a model of dark U(1) DM, we then study both dilution and the signals at various high energy telescopes observing gamma rays, neutrinos and charged cosmic rays. This study enriches the physics case of these experiments, and opens a new observational window on heavy new physics sectors.

hep-ph↗

arXiv2019

Voyager 1 $e^\pm$ Further Constrain Primordial Black Holes as Dark Matter

Primordial Black Holes (PBHs) with a mass $M \lesssim {10^{17}}$g are expected to inject sub-GeV electrons and positrons in the Galaxy via Hawking radiation. These cosmic rays are shielded by the solar magnetic field for Earth-bound detectors, but not for Voyager-1, which is now beyond the heliopause. We use its data to constrain the fraction of PBHs to the dark matter in the Galaxy, finding that PBHs with $M<10^{16}$g cannot contribute more than 0.1% (or less for a lognormal mass distribution). Our limits are based on local galactic measurements and are thus complementary to those derived from cosmological observations.

astro-ph.HE↗

arXiv2018

Asymmetric dark matter: residual annihilations and self-interactions

Dark matter (DM) coupled to light mediators has been invoked to resolve the putative discrepancies between collisionless cold DM and galactic structure observations. However, $γ$-ray searches and the CMB strongly constrain such scenarios. To ease the tension, we consider asymmetric DM. We show that, contrary to the common lore, detectable annihilations occur even for large asymmetries, and derive bounds from the CMB, $γ$-ray, neutrino and antiproton searches. We then identify the viable space for self-interacting DM. Direct detection does not exclude this scenario, but provides a way to test it.

hep-ph↗

arXiv2017

Dark matter line searches towards dwarf galaxies with H.E.S.S

High energy $γ$-rays are powerful probes in the search for annihilations of dark matter (DM) par- ticles in dense environments. In several DM particle models their annihilation produces characteristic features such as lines, bumps or cut-offs in their energy spectrum. The High Energy Stereoscopic System (H.E.S.S.) of imaging atmospheric Cherenkov telescopes is perfectly suited to search for such features from multi-TeV mass DM particles. The Dwarf Spheroidal Galaxies (dSphs) of the Local Group are the most common satellites of the Milky Way and assumed to be gravitationally bound dominantly by DM, with up to O(10 3 ) times more mass in DM than in visible matter. Over the past decade, several observational campaigns on dwarf satellite galaxies were launched by H.E.S.S. amounting to more than 140 hours of exposure in total. The observations are reviewed here. In the absence of clear signals, the expected spectral and spatial morphologies of signal and background are used to derive constraints on the DM particle annihilation cross- section for particle models producing line-like signals. The combination of the data of all the dwarf galaxies allows a significant improvement in the HESS sensitivity.

astro-ph.HE↗

arXiv2017

Dark Matter's secret liaisons: phenomenology of a dark U(1) sector with bound states

Dark matter (DM) charged under a dark U(1) force appears in many extensions of the Standard Model, and has been invoked to explain anomalies in cosmic-ray data, as well as a self-interacting DM candidate. In this paper, we perform a comprehensive phenomenological analysis of such a model, assuming that the DM abundance arises from the thermal freeze-out of the dark interactions. We include, for the first time, bound-state effects both in the DM production and in the indirect detection signals, and quantify their importance for Fermi, AMS, and CMB experiments. We find that DM in the mass range 1 GeV to 100 TeV, annihilating into dark photons of MeV to GeV mass, is in conflict with observations. Instead, DM annihilation into heavier dark photons is viable. We point out that the late decays of multi-GeV dark photons can produce significant entropy and thus dilute the DM density. This can lower considerably the dark coupling needed to obtain the DM abundance, and in turn relax the existing constraints.

hep-ph↗

arXiv2016

Anti-helium from Dark Matter annihilations

Galactic Dark Matter (DM) annihilations can produce cosmic-ray anti-nuclei via the nuclear coalescence of the anti-protons and anti-neutrons originated directly from the annihilation process. Since anti-deuterons have been shown to offer a distinctive DM signal, with potentially good prospects of detection in large portions of the DM-particle parameter space, we explore here the production of heavier anti-nuclei, specifically anti-helium. Even more than for anti-deuterons, the DM-produced anti-He flux can be mostly prominent over the astrophysical anti-He background at low kinetic energies, typically below 3-5 GeV/n. However, the larger number of anti-nucleons involved in the formation process makes the anti-He flux extremely small. We therefore explore, for a few DM benchmark cases, whether the yield is sufficient to allow for anti-He detection in current-generation experiments, such as AMS-02. We account for the uncertainties due to the propagation in the Galaxy and to the uncertain details of the coalescence process, and we consider the constraints already imposed by anti-proton searches. We find that only for very optimistic configurations it might be possible to achieve detection with current generation detectors. We estimate that, in more realistic configurations, an increase in experimental sensitivity at low-kinetic energies of about a factor of 500-1000 would allow to start probing DM through the rare cosmic anti-He production.

hep-ph↗