Speaker
Mr
Kai Schmitz
Description
In models of inflation driven by an axion-like pseudoscalar field, the
inflaton, a, may couple to the standard model hypercharge gauge field
via a Chern-Simons-type interaction, L ⊃ a F F̃. This coupling results
in the explosive production of hypermagnetic fields during inflation,
which has two interesting consequences: (1) The primordial hypermagnetic
field is maximally helical and, thus, capable of sourcing the generation
of nonzero baryon number around the electroweak phase transition (via
the chiral anomaly in the standard model). (2) The gauge field
production during inflation feeds back into the spectra of primordial
perturbations, which leaves an imprint in the stochastic background of
gravitational waves (GWs). In this talk, I am going to discuss the
correlation between these two phenomena. To this end, I will (a) present
an updated study of baryogenesis via hypermagnetic fields after
pseudoscalar inflation and (b) describe the corresponding implications
for GWs. As it turns out, successful baryogenesis is feasible --
provided the axion couples to the gauge fields with a particular
strength. Moreover, in the case of successful baryogenesis, one expects
a characteristic peak in the GW spectrum at frequencies in the MHz
range.
Primary author
Mr
Kai Schmitz
