The indirect searches of Dark Matter (DM), in conjugation with the
so called `missing track searches' at the collider seems to confine fermion
triplet DM mass within a narrow range around $1$ TeV. The canonical picture of
pure triplet fermionic dark matter is in tension since it is under-abundant for
the said mass range. Several preceding studies have shown that the existence of
an extra...
We study the production of Dark Matter (DM) in a minimal freeze-in model during inflationary reheating. We analyze the case where a heavier parent particle decays into DM and a Standard Model fermion in two reheating scenarios: bosonic reheating (BR) and fermionic reheating (FR). We show that for a low reheating temperature, BR and FR scenarios predict different lifetimes and masses for the...
Dirac Leptogenesis is a viable scenario that connects the observed baryon asymmetry of our universe to the possibility that neutrinos are Dirac fermions. After reviewing the basic ingredients of this approach we present two models for parametrically small Dirac neutrino masses. Both constructions also allow for the generation of a lepton asymmetry from out-of-equilibrium particle decays, that...
While the Standard Model (SM) has been extremely successful, it fails to explain the origin of neutrino masses and of the baryon asymmetry of the universe. Extending the SM with right-handed neutrinos in the type-I seesaw framework provides the necessary ingredients to solve both of these problems. In addition, one can predict the PMNS angles and other low-energy parameters if we endow the...
We revisit the framework of axion-like inflation and consider a warm inflation scenario in which the inflaton couples to the topological charge density of non-Abelian gauge bosons whose self-interactions result in a rapidly thermalizing heat bath. Including both dispersive (mass) and absorptive (friction) effects, we find that the system remains in a weak regime of warm inflation (thermal...
The adiabatic growth of a central massive black hole could compress the surrounding dark matter halo, leading to a steeper profile of the dark matter halo. This phenomenon is called adiabatic compression. We investigate the adiabatic compression of wave dark matter - a light bosonic dark matter candidate with its mass smaller than a few eV. Using the adiabatic theorem, we show that the...
In recent years, the asymptotic structure of gravity and gauge theories has been studied extensively. This was, however, done almost exclusively for (asymptotically) flat spacetimes with a few exceptions.
In this talk, I will give an overview of the asymptotic structure of electrodynamics in certain FLRW spacetimes. I will first introduce asymptotic symmetries and then show their relation to...
Axion inflation is an attractive particle physics model of inflation with a rich phenomenology, due to the parity violating production of gauge-fields in this model, which may have implications for the production of gravitational waves, scalar perturbations and the baryon asymmetry. In recent years, a scenario with strong back-reaction of the gauge fields onto the inflaton in this model has...
The behavior of scalar fields in a thermal plasma plays an important role in the study of the early universe, and it is relevant for addressing problems in astrophysics and cosmology. In this talk, we present a calculation of the dissipation rate in a simple scalar model at a finite temperature. We discuss the impact of thermal masses on the quasi-particle kinematics and show the different...
Light scalar fields, such as axions, can play an important role in cosmology. In this talk I will discuss the mechanism of cosmological relaxation of the electroweak scale, which provides a dynamical solution to the Higgs mass hierarchy problem. In the simplest model, the Higgs mass is scanned during inflation by a light field, the relaxion, whose slow-roll dynamics selects a naturally small...
It is common physics knowledge that the N-body problem cannot be solved analytically for $N>2$. Indeed, it has been proven that for general initial conditions the particle trajectories can not be expressed in terms of elementary functions. However, if we consider different observables, e.g., density n-point functions, this theorem does not directly apply. Moreover, when working with such...
Recent Gaia observations suggest that some hypervelocity stars (HVSs) might originate from outside the Galaxy. We ask if these HVSs could come from as far as Andromeda. Therefore, we simulate HVSs originating in Andromeda with initial conditions based on attributes of high velocity stars measured in the Milky Way and a simple model for the gravitational potential of Andromeda and the Milky...
We present a Spin 3/2 FIMP dark matter (DM) candidate. FIMP dark matter is produced via the freeze-in mechanism that
generally implies tiny coupling between the DM and the standard model particles, making DM direct detection and
collider searches almost hopeless. This is not the case for a spin 3/2 DM at low reheating temperature, where direct
detection and collider bounds play a...
Beyond the Standard Model (SM) physics is required to explain both dark matter (DM) and the baryon asymmetry of the universe, the latter possibly generated during a strong first-order electroweak phase transition. While many proposed models tackle these problems independently, it is interesting to inquire whether the same model can explain both. Here, I focus on a DM model featuring an inert...
