Speaker: Mrunal Prashant Korwar, Department of Physics Graduate Student
Abstract: The notion of macroscopic dark matter, made up of multiple constituent particles, provides an intriguing possibility to explain the nature of dark matter. In this thesis, we present theoretical models, formation mechanisms in the early universe, and experimental search strategies for macroscopic dark matter. For the model aspect, we explore two examples: the electroweak symmetric dark monopole, in which the Higgs-portal interaction alters the electroweak vacuum within the monopole, and primordial black holes of both magnetically charged and uncharged types. While both uncharged black holes and magnetic black holes undergo Hawking evaporation, for the latter, the presence of hairy electroweak-symmetric coronas accelerates the Hawking evaporation, making the magnetic black holes extremal. For the formation mechanism, we propose a new production method for monopoles through parametric resonance. We demonstrate that dark monopoles with a radius up to one micron and a mass of up to ten kilotons could account for all dark matter. To search for macroscopic dark matter objects, we find that monopoles with electroweak-symmetric cores generate multi-hit signatures and deposit significant energy in large-volume neutrino detectors, such as the IceCube neutrino detector, which can probe dark matter masses up to one gram. For uncharged primordial black holes, we update constraints from Hawking evaporation using observations of gamma-ray emissions and identify new targets for future exploration. We also discuss potential detection signatures for extremal magnetic black holes.