Seminario
Quando e dove: Giovedì 24 marzo 2022 ore 16, Aula Newton Plesso di Fisica
Relatore: dott. Emanuele Castorina - Università di Milano
Titolo: Testing the equivalence principle in the dark sector
Organizzatori: proff. Guido D’Amico e Massimo Pietroni
Abstract
The equivalence between the inertial and gravitational mass is built-in
the formulation of General Relativity as the curvature of space time. In
the visible sector, the equivalence principle has been tested with
extraordinary precision using torsion balance experiments, but very
little is known about the presence of long range fifth forces in the dark
sector. In this talk I will describe how we can use cosmological data to
test whether dark matter violates the equivalence principle. The
Universe itself will act as a scale that measures if dark matter particles
fall in the same way as ordinary particles. After presenting the main
effects of dark 5fifth forces on cosmological observables like the CMB
and matter power spectrum, I will present the constraints on the
strength of the new interaction using Planck and BAO data. Our results
indicate that equivalence principle violations in the dark sector are at
most a few parts in one thousand, which is the best available bound on
such new forces. Finally, I will discuss the implications of our findings in
the broader context of the constraints on the equivalence principle in
the visible sector, and what they imply for the coupling between the
dark matter and the standard model, which is of relevance for direct
detection experiments of dark matter.
