I will show how spectral features in a stochastic gravitational-wave background can be used to probe the properties of long-lived beyond-the-Standard-Model particles. Such particles can induce a temporary period of early matter domination, leaving characteristic frequency scales in a primordial gravitational-wave spectrum that encode the onset and end of this epoch. For freely propagating backgrounds, these features determine the particle … Read More

Abstract: A dark-sector gauge symmetry implies two automatically stable dark-matter candidates: the lightest particle with a dark electric charge, and the lightest monopole with a dark magnetic charge. We consider monopole production by a thermal phase transition in the early Universe. We show that, generically, the abundance of dark monopoles is negligible with respect to that of dark particles. There is … Read More

Abstract: Motivated by the swampland program, it has been proposed that a tower of massive Kaluza-Klein (KK) gravitons from a compactified flat extra dimension can be dark matter, with the heavier modes constantly cascading to lighter ones. The phenomenology crucially depends on the rate at which a massive KK mode decays to lighter modes. We show that, up to mild … Read More

Abstract: It was recently shown that standard sub-GeV dark matter (DM) candidates can be effectively probed by large neutrino observatories via annual modulation of the total photomultiplier hit rate. That work focused on the production of light by the excitation of scintillator molecules and considered the JUNO detector, surpassing limits from dedicated dark-matter detectors and reaching theoretical targets. Here, we significantly … Read More

Andrea Minotti Title: “Cosmic Birefringence from a pseudo-scalar field” Abstract: “When polarized electromagnetic radiation propagates through a region of space permeated by a pseudo-scalar field, the plane of linear polarization undergoes a rotation. The rotation angle depends on the field’s values when the radiation is emitted and when it is detected and does not depend on the frequency of the radiation. … Read More