PIRSA ID: 23110081
Série :
Event Type: Seminar
Domaine(s) scientifique(s) : Particle Physics
Date de fin : 2023-11-28
Speaker(s): Zach Weiner
The cosmic microwave background is a sensitive probe of early-Universe physics, and yet fundamental constants at recombination can differ from their present-day values due to degeneracies in the standard cosmological model. Such scenarios have been invoked to reconcile discrepant measurements of the present-day expansion rate, but even absent such motivation they raise the intriguing possibility of yet-undiscovered physics coupled directly to Standard Model particles. I will discuss theories in which a new scalar field shifts the electron's mass at early times; viable models are already stringently constrained by measurements of quasar absorption lines, the abundances of light elements, and the universality of free fall. I will show that the remaining parameter space is exactly that which allows not only the primary cosmic microwave background but also low-redshift distances to be consistent with observations. After presenting the results of parameter inference I will discuss additional cosmological and laboratory signatures of the model.
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Zoom link https://pitp.zoom.us/j/99705853481?pwd=MTZRWC9hREkvOXpiZkxCM3UvdnRNQT09