The decay of a scalar condensate is an important phenomenon in cosmology, including inflation and reheating.
We compute the decay of a scalar condensate using two distinct methods: (1) an approach based on the parametric resonance of the mode functions of the daughter particles, and (2) an approach based on the effective action given by the sum of Feynman diagrams. We then demonstrate that,...
The relic abundance of Dark Matter (DM) produced via thermal freeze-in is sensitive to the thermal history during and after cosmic reheating. In minimal models, this opens up the possibility to make predictions for collider observables by combining the requirement to match the DM relic abundance with observations of the Cosmic Microwave Background (CMB). We assess the impact of thermal...
Recent studies on the dark photon (DP) production in collapsing stars argue that the cooling effect induced by DPs can hinder supernova explosions and lead to a “failing supernova” constraint on the photon-DP mixing parameter 𝜀. In order to verify the idea, we perform two-dimensional neutrino-radiation hydrodynamic simulations coupled with the DP production with the masses of 0.3 and 0.45 MeV....
Primordial black holes (PBHs) are compelling candidates for dark matter (DM), although current observations strongly limit their ability to account for the total DM abundance. In scenarios where the remaining DM consists of weakly interacting massive particles (WIMPs), the latter are expected to accumulate around PBHs, forming dense dark matter spikes whose properties can be predicted rather...
Quantum gravity theories often predict spacetime fluctuations at the Planck scale, which could induce observable quantum decoherence effects. Neutrinos provide a uniquely sensitive probe of such phenomena: because they interact only via the weak force and gravity, they can maintain quantum coherence over astrophysical distances. In this talk, I will present a search for quantum decoherence...
The Standard Model (SM) of particle physics is an extremely successful theory, and in many areas, it agrees to extremely high precision with experimental measurements; however, several shortcomings—such as the lack of a feasible dark matter candidate or the existence of non-zero neutrino masses—fuel belief that it is not the final theory of Nature. Despite the decades-long experimental and...
The landmark multi-messenger observations of the binary neutron star (BNS) merger GW170817 provided firm evidence that such mergers can produce short gamma-ray bursts (sGRBs). However, the scarcity of BNS detections in recent gravitational-wave (GW) observing runs raises a critical question: are BNS merger rates high enough to account for the full population of observed sGRBs?
We address this...
One of the greatest outstanding mysteries in physics is the observed baryon asymmetry of the Universe. Experimental constraints have made it clear that neither CP asymmetry in the quark sector, nor CP asymmetry in the lepton sector, are sufficient to explain the size of the observed baryon asymmetry. One viable explanation is the leptogenesis mechanism of Fukugita and Yanagida wherein lepton...
Whether neutrinos are Dirac or Majorana remains one of the deepest open questions in particle physics. An especially compelling possibility is that they are quasi‑Dirac: each active neutrino paired with a nearly degenerate sterile partner, split by a tiny Majorana mass plausibly generated by Planck‑scale or string‑theoretic lepton‑number violation. The signature is an ultra‑long‑baseline...
Cryogenic scintillating calorimeters (CSCs) with transition-edge sensor (TES) readout have demonstrated excellent sensitivity to dark matter–nucleus and neutrino–nucleus scattering. The OνDES project extends this technology to lower energy thresholds, enabling searches for dark matter–electron and neutrino–electron scattering.
In this talk, I will introduce the OνDES project and the...
As a consequence of deviations from special relativity, Lorentz-Invariance Violation may affect the propagation of astrophysical neutrinos. In particular, it may introduce an additional shift with respect to the intrinsic time delay between neutrino detection and the signature of another messenger, and the possible faster-than-light component would be subject to decay, affecting the observable...
Several Quantum Gravity models allow for a spontaneous violation of Lorentz Invariance close to the Planck scale, leading to non-trivial energy-dependent dispersion relations for the photon in vacuum. As a result, gamma-rays emitted simultaneously at different energies that travel very long distances can potentially accumulate different measurable delays in their time of flight towards the...
Lorentz invariance may be modified in quantum gravity scenarios, potentially leading to observable effects even far below the Planck scale. Ultra-high-energy cosmic rays provide a unique laboratory to probe such deviations. In this contribution, we exploit, for the first time, fluctuations in the muon content of extensive air showers measured at the Pierre Auger Observatory to constrain...
