The two-body Decaying Dark Matter (DDM) model extends the standard cold dark matter paradigm by allowing dark matter particles to decay into a massive daughter particle and a relativistic species. This scenario arises naturally in particle physics and has testable implications for cosmological observables. In this talk, I will introduce the model and present updated constraints on the dark...
The axion can address the strong CP problem and also provide a promising dark matter candidate in the form of a condensate of zero-momentum modes. In addition, axion models feature an unavoidable “hot” ensemble of thermally-produced axions acting as dark radiation and thus subject to present and future constraints from the effective number of neutrinos $N_\mathrm{eff}$.
I will concentrate on...
Sterile neutrinos with masses on the $\mathrm{eV}$ scale are promising candidates to account for the origin of neutrino mass and the reactor neutrino anomalies. The mixing between sterile and active neutrinos in the early universe could result in a large abundance of relic sterile neutrinos, which depends on not only their physical mass $m_{\rm phy}$ but also their degree of thermalization,...
