Weizmann Institute

by Michael Waterbury (University of California, Irvine), Prof. Yuri Shirman

Wednesday 11 May 2022, 11:00 → 14:00 Asia/Jerusalem

SRitp, Physics Library (Weizmann Institute of Science)

11:00: Michael Waterbury (Technion)

Dark Matter Freeze Out during an Early Cosmological Period of QCD Confinement

Standard lore states that there is tension between the need to accommodate the relic density of a weakly interacting massive particle and direct searches for dark matter. However, the estimation of the relic density rests on an extrapolation of the cosmology of the early Universe to the time of freeze out, untethered by observations. We explore a nonstandard cosmology in which the strong coupling constant evolves in the early Universe, triggering an early period of QCD confinement at the time of freeze out. We find that depending on the nature of the interactions between the dark matter and the Standard Model, freeze out during an early period of confinement can lead to drastically different expectations for the relic density, allowing for regions of parameter space which realize the correct abundance but would otherwise be excluded by direct searches.

13:00:  Yuri Shirman (UC Irvine)

Chirality changing RG flows: dynamics and models

I will consider SUSY theories which exhibit confinement without chiral symmetry breaking. When global symmetries of such s-confining theories are weakly gauged RG flows may result in chirality change. Possible changes include appearance of a mass gap in theories with chiral matter content, appearance of massless composite chiral generations, as well as more general changes of the chiral structure of the models. I will discuss the dynamics responsible for these chirality flows, model building tools and the necessary conditions for generation of mass gaps. As an application, I will present examples of globally consistent string models with even number of generations in UV which flow to 3 generations in IR.