Adrian Thompson (Northwestern)

11:00am Wednesday May 21, 2025
Webinar

What neutron stars tell us about baryon number violation, GeV dark matter, and baryogenesis

Rare processes in laboratory and within astrophysical environments can be highly sensitive probes of baryon-number-violating interactions at the TeV scale. We demonstrate the power of neutron stars to constrain baryon-number violation by considering a minimal extension of the standard model involving a TeV-mass scalar mediator and a GeV scale Majorana fermion. We find that a deltaB=2 mass-loss process in binary pulsar systems via neutron decays to dark fermions and a photon, and the subsequent annihilation of the dark photon into mesons, places stringent constraints on the model parameter space. These limits will become much stronger, due to the possibility of strange baryon decays at the tree level, if the neutron star equation of state is hyperonic. We compare these constraints with ongoing and future collider experiments, oscillations, and dinucleon decay searches at future large-scale neutrino experiments, finding that the binary pulsars bounds on couplings are significantly tighter for specific flavor combinations. Finally, I discuss how these constraints contend with the viable parameter space for successful Baryogenesis without washout of the baryon asymmetry of the universe.