Princeton University Dark Cosmos Seminar
Freezing-in the Axiverse
Abstract - 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 presence of N light axions is constrained by the number of relativistic degrees of freedom N_eff. Under generic assumptions 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.
Date & Time
January 27, 2026 | 4:00pm – 5:30pm
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01/27/2026 16:00
01/27/2026 17:30
Princeton University Dark Cosmos Seminar
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Topic: Freezing-in the Axiverse
Speakers: Christipher Dessert, Flatiron Institute
More: https://www.ias.edu/sns/events/princeton-university-dark-cosmos-seminar-43
Abstract - 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 presence
of N light axions is constrained by the number of relativistic degrees
of freedom N_eff. Under generic assumptions 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.
Jadwin Hall, Joe Henry Room
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Location
Jadwin Hall, Joe Henry RoomSpeakers
Christipher Dessert, Flatiron Institute