| Dark Radiation Isocurvature from Cosmological Phase Transitions |
| Peizhi Du, Rutgers University |
| Event Type: HEP Seminar |
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| Time: 2:00 PM - 3:15 PM |
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| Location: 726 Broadway, 940, CCPP Seminar |
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| Abstract: Cosmological first-order phase transitions are typically associated with physics beyond the Standard Model, and thus of great theoretical and observational interest. In this talk, I will show that a broad class of non-thermal first-order phase transitions could generate distinct large-scale isocurvature in dark radiation that can be observable in the CMB. We derive constraints on Delta N_eff from phase transitions based on CMB+BAO data, which can be much stronger than that from adiabatic initial conditions. I will also demonstrate that since perturbations of dark radiation have a non-Gaussian origin, searches for non-Gaussianity in the CMB could also place a stringent bound on Delta N_eff. Link to the Event Video |