Giacomo Ferrante: "No room for monopole dark matter"

Thursday 2 Apr 2026, 13:30 → 15:00 Europe/Rome

Sala Direzione INFN

The magnetic monopole of a dark sector represents a compelling dark matter candidate, as its stability naturally follows from the non-trivial topology of vacuum. I will revisit the computation of the monopole abundance generated by a thermal phase transition, in the simplest model admitting monopole solutions. I will explore the three regimes where the phase transition is second order, weakly first order, or supercooled, identifying the regions of parameter space where the monopole relic density matches that of dark matter. However, a dark sector featuring monopoles necessarily contains stable electrically-charged particles, namely massive vector bosons. I will show that the abundance of gauge bosons always greatly exceeds the monopole one. This result leads to the conclusion that dark monopoles cannot constitute a sizeable fraction of dark matter in the minimal model, contrarily to what has been claimed in the literature.