Astroparticle
Dark Matter and New Physics
Dark matter accounts for approximately 27% of the universe’s total energy-matter content and around 85% of its matter. While its presence is inferred through a range of observations—spanning from galaxy dynamics on kiloparsec scales to the cosmic microwave background—its fundamental nature remains one of the most significant open questions in physics. The dark matter landscape presents a variety of possibilities, including new particles beyond the Standard Model, with mass scales ranging from the ultra-light ZeV to the ultra-heavy PeV regime, or even non-particle, non-baryonic origins.
Our research group is focused on the search for dark matter through astroparticle and cosmological observations. We investigate dark matter primarily through indirect searches, analysing fluxes of cosmic rays and radiation across multiple wavelengths to identify potential dark matter signatures. Additionally, we study the cosmological imprints that dark matter may have left in the early universe, helping to provide constraints on its properties and interactions.
Another important aspect of our research involves exploring the existence of new particles beyond the Standard Model, such as QCD axions and other axion-like particles, which may or may not serve as dark matter candidates. We also use observations of stars to place constraints on the properties of these new particles, helping to refine our understanding of their potential role in the universe.
Our approach is twofold: on the one hand, we engage in theoretical modelling, predicting novel signatures of dark matter and other new physics phenomena; on the other hand, we focus on devising and optimising search strategies, continually proposing new and innovative pathways for the detection of dark matter.
Origin and Transport of Cosmic Rays
Cosmic rays, high-energy particles constantly bombarding Earth, remain enigmatic in many respects. Believed to carry messages from the Galaxy’s most energetic events, the details of their production and journey through space to Earth continue to be debated. Over the past decade, a wealth of new experimental data has ushered in a precision era for cosmic-ray physics. These high-accuracy measurements reveal unexpected features in so-called primary and secondary cosmic-ray spectra, challenging long-held paradigms about their origins.
Our team’s research delves deeply into the local cosmic-ray spectra, which may hold clues about cosmic-ray origins. To interpret these data more accurately, we are examining key theoretical uncertainties, especially those tied to cosmic-ray nuclei fragmentation cross-sections. As they represent a major source of uncertainty, we are actively advocating for new measurements of isotopic fragmentation cross-sections at particle colliders. Such data will enhance models accuracy and allow us to derive richer insights from cosmic-ray observations.
Alongside these efforts, we are developing minimalist phenomenological models that achieve good fits (in a statistical sense) to current data. These models not only refine our understanding of cosmic-ray transport but also allow us to set stringent limits on WIMP-like dark matter candidates through analysis of cosmic-ray antiparticles.
Our studies have also indicated that some universal features in cosmic-ray spectra may stem from the rigidity dependence of the diffusion coefficient. Further, recent data from balloon and space-based calorimeters—especially CALET and DAMPE—have revealed intriguing spectral features near the PeV energy range, approaching the upper limit for galactic cosmic-ray accelerators. The origin of these high-energy features remains a key area of investigation.
Additionally, our newest research direction focuses on the microphysics of charged particle diffusion in magnetohydrodynamic plasma, an essential factor in cosmic-ray transport. These combined efforts aim to provide new insights into the complex mechanisms driving cosmic-ray propagation and their implications for exotic physics.
Recent Publications
- F. Calore, et al., « Uncovering axionlike particles in supernova gamma-ray spectra », Phys.Rev.D 109 (2024) 4, 043010
- F. Calore, A. Dekker, and P. D. Serpico, « Constraints on light decaying dark matter candidates from 16yr of INTEGRAL/SPI observations », Mon.Not.Roy.Astron.Soc. 520 (2023) 3, 4167-4172
- F. Calore, et al., « AMS-02 antiprotons and dark matter: trimmed hints and robust bounds », SciPost Phys. 12 (2022) 5, 163
- A. Esmaili, and P. D. Serpico, « First implications of Tibet AS-gamma data for heavy dark matter », Phys.Rev.D 104 (2021) 2, L021301
- L. Mastrototaro, et al., « Heavy sterile neutrino emission in core-collapse supernovae: Constraints and signatures », JCAP 01 (2020) 010
Codes and Databases
- Template bank for analysis of INTEGRAL/SPI 16yr data and dark matter analysis
- Software to process and analyse public Fermi-LAT gamma-ray in the direction of dwarf spheroidal galaxies and set upper limits on dark matter particles
- USINE semi-analytical code design by David Maurin (LPSC) used to compute local galactic cosmic rays fluxes and investigate theoretical/experimental uncertainties.