In an era characterized by a wide range of astrophysical and cosmological observations, the synergy of data with sophisticated simulations has enabled us to probe interesting phenomenological paradigms of particulate dark matter (DM). Self-scattering of particulate DM within the dark sector can contribute to the thermalization of the central region of a galactic halo. The self-interaction...
Pseudo Nambu-Goldstone (pNG) bosons can play important roles in particle physics, such as being a light dark matter (DM), the QCD axion to solve the strong CP problem, and so on. I point out that such a pNG boson is naturally realized by the finite modular symmetry, which may originate from the geometry of extra dimensions in the superstring models. An accidental global U(1) symmetry...
Celestial bodies can cathalize WIMP annihilations, providing a promising way to detect them. Moreover, celestial bodies and direct detection probe the same WIMP-nucleus scattering process in a complementary way, allowing to remove the uncertainty on the velocity distribution. Thanks to their gravitational acceleration celestial bodies also allow to extend the experimental sensitivity to a...
The early Universe provides a unique environment to explore fundamental physics, offering extreme conditions that allow theoretical models to be tested, and opening the possibility to probe particle physics at energy scales far beyond the reach of current and future accelerators. In this respect, among the various cosmological phenomena of interest, first-order phase transitions play a...
In this talk, I will explore Non-Standard Neutrino Interactions (NSIs) and their effects on neutrino oscillation parameters. I will discuss the LMA-Dark solution and the degeneracies induced by NSIs in the measurement of (\delta_{CP}). Additionally, I will examine the impact of NSIs on solar and atmospheric neutrinos.
Radiative corrections to the QCD θ parameter have been evaluated in terms of the imaginary part of the radiative quark mass phase, e.g. using the Fujikawa method. We have evaluated the radiative correction to the QCD θ at the 2-loop level by direct calculation of the Feynman diagram using a toy model with CP-violating Yukawa coupling. We show that the diagrammatic method is consistent with the...
During the accretion phase of a core-collapse supernova (SN), dark-photon (DP) cooling can be largest in the gain layer below the stalled shock wave. In this way, it could counter-act the usual shock rejuvenation by neutrino energy deposition and thus prevent the explosion. This peculiar energy-loss profile derives from the resonant nature of DP production. The largest cooling and thus...
In this talk I will introduce a novel particle physics framework addressing multiple cosmological tensions, including discrepancies in the Hubble parameter, S8, and Lyman-\alpha forest data. This model, SIDR+z_t (Self-Interacting Dark Radiation with transition redshift), features an inelastic dark matter (IDM) scenario coupled with dark radiation under a dark gauge symmetry. The model...
The kinetic mixing with dark U(1) gauge can mediate the supersymmetry breaking with significant distortions of the mass spectrum and distinct phenomenology. This talk is based on our recent paper (arXiv: 2412.17777).
We explore the possibility of solving the dark energy and the coincidence problems by postulating the massless sector of closed strings. This sector constitutes the gravitational multiplet of string theory and, when applied to four-dimensional cosmology, predicts that \textit{the expansion of an open Universe defined in string frame is readily accelerating}. We confront the prediction with the...
We discuss an SO(10) model where a dimension five operator induces kinetic mixing between the abelian subgroups at the unification scale. We discuss gauge coupling unification and proton decay in this model, as well as the appearance of superheavy quasistable strings, which can explain the PTA data.
In an era characterized by a wide range of astrophysical and cosmological observations, the synergy of data with sophisticated simulations has enabled us to probe interesting phenomenological paradigms of particulate dark matter (DM). Self-scattering of particulate DM within the dark sector can contribute to the thermalization of the central region of a galactic halo. The self-interaction...
The dynamics of cosmic reheating, that is, on how the energy stored in the inflaton is transferred to the standard model (SM) thermal bath, is largely unknown. In this work, we show that the phenomenology of the nonbaryonic dark matter (DM) ultraviolet freeze-in production strongly depends on the dynamics of the cosmic-reheating era. Using a general parametrization for the Hubble expansion...
