Speaker: Junwu Huang
Title: Abstract:Cosmic axion strings II: A cosmological plasma collider
Zoom: https://zoom.us/j/186024391
Host: Markus Luty
Abstract : We continue our discussion of early and late time signatures of axion strings by considering the effects of electromagnetic field on the axion string. Axion strings passing through galaxies obtain a huge charge and current density, which is neutralized by a dense plasma of bound state Standard Model particles forming a one dimensional "atom". The charged wave packets on the string, as well as the dense plasma outside, travel at nearly the speed of light along the string. The collisions of these packets of plasma can have luminosities up to seven orders of magnitude larger than the solar luminosity, and last for thousands of years, making them visible at radio telescopes even when they occur cosmologically far away. The new observables are complementary to the CMB observables discussed last week, and are sensitive to a similar motivated parameter range, allowing for non-trivial cross correlations.
User:
High-Energy Seminars
Time:
11:00am - 12:00pm
Send Reminder:
Yes - 0 days 8 hour 0 minutes before start
Description:
Speaker: Austin Joyce
Title:Cosmological correlators from the boundary
Zoom: https://zoom.us/j/186024391
Abstract:
The large-scale correlations that we observe in the distribution of matter in the universe have their origins in primordial perturbations produced prior to the hot big bang—likely during a period of inflationary expansion. Interestingly we do not directly observe the inflationary epoch, but instead infer its dynamics from correlations residing on the late time boundary of the inflationary spacetime, where the universe reheats. This motivates us to ask whether we can understand things directly on this asymptotic boundary, without making explicit reference to bulk time evolution. I will describe recent progress in this direction, including aspects of how the bulk dynamics is encoded on the boundary.
User:
High-Energy Seminars
Time:
1:30pm - 2:30pm
Send Reminder:
Yes - 0 days 8 hour 0 minutes before start
Description:
Speaker: Xiaochuan Lu
Title: Constraining BSM custodial violations beyond the oblique framework
Zoom: https://zoom.us/j/186024391
Host: Markus Luty
Abstract: BSM custodial violations are believed to be strongly constrained by electroweak precision measurements. In particular, they result in a nonzero Peskin-Takeuchi T parameter, which is experimentally bounded at the per-mille level. However, the T parameter constraint only applies to oblique BSM physics. When the BSM effects are not oblique, T parameter is no longer an observable, and it fails to serve as an indicator of BSM custodial violations. We take a first step at addressing this problem by working with SMEFT at the dim-6 and tree level. We identify new observables that can serve as unambiguous indicators of BSM custodial violations.
