Long-lived particles (LLPs) could serve as a portal to hidden sectors addressing different open problems of the Standard Model. Among these, the evidence for neutrino masses and mixings—observed in neutrino oscillation experiments—stands out as particularly promising. A simple extension to the SM involves the inclusion of heavy right-handed neutrinos, commonly known as heavy neutral leptons...
Liquid argon Time Projection Chambers (LArTPCs) have proven to be powerful instruments for detecting weakly interacting particles predicted by many beyond the Standard Model (BSM) scenarios. Thanks to their location at CERN, the ProtoDUNE detectors can intercept a sizeable flux of such particles, produced when the 400 GeV protons from the Super Proton Synchrotron (SPS) impinge on a fixed...
In this talk, we revisit a class of lepton-flavor non-universal gauge extensions of the Standard Model that provide a compelling framework for generating neutrino masses and mixing angles via a high-scale seesaw mechanism, while ensuring exact proton stability to all orders in the effective field theory. This setup naturally accommodates minimal thermal leptogenesis, offering a robust...
Spallation neutron sources can provide an intense source of new, light particles from the decay at rest of pions, muons, and kaons.
Considering a variety of spallation sources around the world, we study the sensitivity of existing neutrino detectors to the decay of these new particles.
At J-PARC, we show that the fast, magnetized, gaseous argon chambers of the ND280 detector could place...
We present a comprehensive theoretical framework describing single pion resonant production through inelastic dark fermion–nucleon interactions mediated by resonances in the GeV-scale regime. Building upon the Rein–Sehgal approach, we derive differential cross sections for processes in which an incoming dark fermion scatters off a nucleon, exciting a resonance that subsequently decays into a...
The PADME experiment at the Frascati National Laboratory of INFN has performed a
search for the hypothetical X17 particle, by observing the product of the collisions
of the positron beam from the DAΦNE LINAC on a diamond fixed target.
The beam energy has been varied in the range
265–300 MeV, corresponding to values of √s between 16.4 and 17.5 MeV,
completely covering the the CoM...
In the last years, the efforts towards finding subGeV new physics have increased. This Light Dark World is vast and unknown, however, we know that the components of different theories must live in that world. From the experimental side, there is also a great effort to disentangle and understand what could hide the Light Dark World. NA64 is a fixed target experiment at CERN SPS that search for...
Ultralight particles, with a mass below the electronvolt scale, exhibit wave-like behavior and have arisen as a compelling dark matter candidate. A particularly intriguing subclass is scalar dark matter, which induces variations in fundamental physical constants. However, detecting such particles becomes highly challenging in the mass range above $10^{-6}\,\text{eV}$, as traditional...
Cosmological observations, such as Big Bang Nucleosynthesis (BBN) and the Cosmic Microwave Background (CMB), provide vital insights into the early Universe, allowing us to trace its evolution to times as short as $t \sim 0.01$ s and to test extensions of the Standard Model. Accurately modeling the non-trivial dynamics of neutrinos typically requires solving a system of Boltzmann equations...
Despite being an elegant mechanism to explain Dark Matter (DM) production, freeze-in introduces challenges: If DM interacts via non-renormalizable operators, the predictions are highly sensitive to initial conditions, such as the reheating temperature of the universe. These issues are particularly relevant in models in which the universe deviates from radiation domination and the entropy of...
Light sterile neutrinos, $\nu_s$, are often introduced to explain an anomalous deficit in the electron antineutrino flux from nuclear reactors. If they exist, sterile neutrinos would also be produced in collapsing massive stars through the active-sterile neutrino oscillation. In order to investigate the impacts of sterile neutrinos on supernova dynamics, we perform two-dimensional...
Recent observations of a variety of ionization tracers have revealed an unexpectedly high ionization rate in the Central Molecular Zone (CMZ), that cannot be explained by ionization of cosmic rays. The current observations point to a source of particles that is very concentrated around the Galactic Center and should emit low energy ionizing particles (to avoid propagating too far away from the...
In this talk, I will discuss minimal realizations of light thermal dark matter (DM) candidates. These scenarios typically require a light mediator to ensure sufficient DM annihilation rates. We demonstrate that such mediators can arise from additional Higgs doublet(s). Within this framework, we focus on two specific scenarios: (1) Forbidden DM, where DM predominantly annihilates into SM...
The ANAIS-112 experiment has completed nearly eight years of continuous data taking, aiming to test the annual modulation signal reported by the DAMA/LIBRA collaboration, using the same NaI(Tl) target and detection technique. Located at the Canfranc Underground Laboratory, ANAIS-112 has accumulated over 800 kg·yr of exposure, achieving excellent long-term stability and background control. In...
The recent laser excitation of the low-lying Th-229 isomer transition is starting a revolution in ultralight dark matter searches. The enhanced sensitivity of this transition to the large class of dark matter models dominantly coupling to quarks and gluons will ultimately allow us to probe coupling strengths eight orders of magnitude smaller than the current bounds from optical atomic clocks,...
We explore the interplay between dark matter scattering and solar dark photon absorption in two dark matter models with light dark photon mediators. Sub-keV dark photons, abundantly produced in the solar core, provide complementary detection channels to scattering of dark matter from the halo. Incorporating astrophysical and cosmological constraints—including dark matter self-interactions and...
Axions and axion-like particles (ALPs) remain compelling dark matter (DM) candidates, provided that the associated Peccei-Quinn (PQ) symmetry breaking scale is sufficiently large to ensure cosmological stability. In this talk, I will explore a novel framework in which ALPs possess flavor-violating (FV) couplings to Standard Model (SM) quarks, allowing them to be produced via freeze-in in the...
Ultralight scalar fields that interact with Standard Model particles through electromagnetic and electrophilic couplings can be efficiently sourced by compact stars, leading to the emergence of long-range forces within binary systems. In certain regimes, these scalars may also be emitted from the stars, giving rise to distinctive observational signatures. In this talk, I will present...
Invited talk (overview)
Direct detection experiments lose sensitivity to light dark matter because of the small energy deposition in nuclear recoil events. Scenarios where dark matter is boosted to relativistic velocities thus provide a promising means to constrain sub-GeV dark matter particles. Cosmic-ray upscattering is a particularly appealing boosting mechanism as it does not require any assumptions beyond dark...
Axion-like particles (ALPs) can account for the observed dark matter (DM) of the Universe and if their masses are at the eV scale, they can decay into
infrared, optical and ultraviolet photons
{with a decay lifetime larger than the age of the Universe}.
We analyze multi-wavelength data obtained from the central region of Messier 87 (M87) galaxy
by several telescopes, such as, Swift,...
Apart from its gravitational interactions, dark matter (DM) has remained so
far elusive in laboratory searches. One possible explanation is that the relevant interactions
to explain its relic abundance are mainly gravitational. In this work we consider an extra-
dimensional Randall-Sundrum scenario with a TeV-PeV IR brane, where the Standard
Model is located, and a GeV-TeV deep IR (DIR) one,...
We demonstrate the possibility of testing Heavy Neutral Leptons (HNLs) using "cosmic ray beam-dumps'' : setups where high-energy incident cosmic rays impinge on the Earth's atmosphere and then on the Earth's surface. We focus on HNL production from atmospherically produced parent meson decays, and examine them as a possible explanation of the appearing Cherenkov showers observed by the SHALON...
In this talk I will present a new potential signature of supernovae axion-like particles (ALPs) in neutrino water Cherenkov detectors. If ALPs couple to protons, then they can be detected through ALP absorption on free protons, $a\ p→p\ γ$, where the resulting photon has approximately the energy of the ALP. This new signature is complementary to the usual one from oxygen de-excitation, and...
Superconducting nanowire single-photon detectors (SNSPDs) have rapidly evolved into powerful tools for applications spanning quantum computing to precision photodetection. In this work, we extend their impact into astroparticle physics by demonstrating their capability to detect sub-MeV Dark Matter. Utilizing an SNSPD fabricated from Niobium Nitride (NbN), we achieve a remarkably low energy...
Scalar-tensor theories are a popular extension of gravity where a light scalar degree of freedom non-minimally couples to the gravitational sector. Despite existing experimental tests for such modifications from general relativity, there is still no conclusive evidence for or against these theories. A possible reason for this is the presence of screening mechanisms, which can hide the scalar...
