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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:2
UID:UW-Physics-Event-9515
DTSTART:20260202T190000Z
DTEND:20260202T203000Z
DTSTAMP:20260413T151510Z
LAST-MODIFIED:20260303T150504Z
LOCATION:Chamberlin 5280
SUMMARY:Freezing-in the Axiverse\, Theory Seminar (High Energy/Cosmolo
 gy)\, Christopher Dessert\, Flatiron Inst.\, New York
DESCRIPTION:The presence of light axions in the infrared is a generic 
 feature of many ultraviolet (UV) scenarios\, including string theory\,
  with the number of such axions N naturally O(10-100). Even when these
  axions interact very weakly with the Standard Model (SM)\, the presen
 ce of N light axions is constrained by the number of relativistic degr
 ees of freedom N_eff. Adopting an effective field theory approach\, I 
 compute the freeze-in abundance of Axiverse axions. Under generic assu
 mptions for the structure of the axion-Standard Model couplings\, the 
 predicted N_eff may be already excluded by Planck or probed by ongoing
  cosmic microwave background surveys like Simons Observatory. Event re
 cording: https://youtu.be/ZTqr242QfjE
URL:https://www.physics.wisc.edu/events/?id=9515
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