David Cyncynates (U. Washington)

Date: Tue. February 25th, 2025, 11:30 am-12:30 pm
Location: Rock 221 Foldy Room

Scalar relics from the hot big bang

Abstract: Motivated by the unexplained origins of dark matter and the cosmological constant, fifth-force experiments provide an important avenue to address major open questions in physics. These experiments take place at low energies, probing interactions among atoms, nucleons, or electrons in atomic energy levels, and are agnostic to the UV origin of any new force. However, such interactions, if present, lead to dynamics in the early Universe that can have cosmological implications. In this talk, I will compute the effect of the early Universe plasma on the scalar field, accounting for the full structure of the Standard Model—spontaneous symmetry breaking, dimensional transmutation, and the running of gauge couplings. We will see that the resulting relic abundance of the fifth-force-carrying scalar field is largely independent of how it couples to the Standard Model, ultimately pointing to a cosmologically preferred region of experimental parameter space.