Probing $\nu$-physics in cosmology with phase-shift

by Dr Subhajit Ghosh (University of Texas)

Friday 5 Dec 2025, 14:30 → 15:30 Asia/Kolkata

A304 and on zoom

In this talk, I will discuss new probes of neutrino interactions in cosmology, specifically using the cosmic microwave background (CMB). A phase shift in the acoustic oscillations of CMB spectra is a characteristic signature of the presence of non-photon species with a sound speed different from that of the photons. Focusing on neutrino self-interactions and dark matter neutrino interactions, I will demonstrate how these interactions imprint changes in the acoustic phase shift and can be probed using data. I will exhibit the potential of future CMB and 21-cm surveys to probe these interactions. I will also discuss models to realize strong neutrino self-interaction cosmology without violating stringent laboratory and BBN constraints.