Pheno & Vino Seminar, Gordon Krnjaic, Perimeter, "Can the baryon asymmetry arise from initial conditions?"

Tue, Nov 8, 2016, 4:00 pm to 5:30 pm
Jadwin 303
In this talk, I'll quantify the challenge of explaining the baryon asymmetry using initial conditions in a universe that undergoes inflation. Contrary to lore, such an explanation is possible if net B−L number is stored in a light bosonic field with hyper-Planckian initial displacement and a delicately field velocity prior to inflation. However, such a construction may require extremely tuned couplings to ensure that this asymmetry is viably communicated to the Standard Model after reheating; the large field displacement required to overcome inflationary dilution must not induce masses for Standard Model particles or generate dangerous washout processes. While these features are inelegant, this counterexample nonetheless shows that there is no theorem against such an explanation. I'll also comment on potential observables in the double β-decay spectrum and on model variations that may allow for more natural realizations.