Theory Seminar (High Energy/Cosmology) |
Events During the Week of April 10th through April 17th, 2022
Monday, April 11th, 2022
- No events scheduled
Tuesday, April 12th, 2022
- No events scheduled
Wednesday, April 13th, 2022
- No events scheduled
Thursday, April 14th, 2022
- No events scheduled
Friday, April 15th, 2022
- A Cosmological Lithium Solution from Discrete Gauged Baryon Minus Lepton Number
- Time: 1:00 pm
- Place: Chamberlin 5280
- Speaker: Seth Koren, University of Chicago
- Abstract: We propose the infrared gauge symmetry of our sector includes an unbroken discrete gauged subgroup of baryon minus lepton number of order 2 x 3 colors x 3 generations = 18, the inclusion of which does not modify local physics. We UV complete this at Λ as the familiar U(1)_{B-NcL} Abelian Higgs theory, and the early universe phase transition forms cosmic strings which are charged under an emergent higher-form gauge symmetry. These topological defects catalyze interactions which turn 3 baryons into 3 leptons at strong scale rates in an analogue of the Callan-Rubakov effect.
The cosmological lithium problem---that the observed primordial abundance is lower than theoretical expectations by a factor of a few---is perhaps the most statistically significant anomaly of SM+ΛCDM, and has resisted decades of attempts by cosmologists, nuclear physicists, and astronomers alike to root out systematics. We write down a model in which B-NcL strings superconduct bosonic global baryon plus lepton currents and catalyze solely 3p+ → 3e+. We suggest that such cosmic strings have disintegrated O(1) of the lithium nuclei formed during Big Bang Nucleosynthesis and estimate the rate, with our benchmark model finding Λ∼108 GeV gives the right number density of strings. - Host: George Wojcik