Sep 25 – 27, 2024
IMSc Chennai
Asia/Kolkata timezone

New Physics with $N_{\rm eff}$ in the CMB

Sep 26, 2024, 4:00 PM
15m
Ramanujan Auditorium (IMSc Chennai)

Ramanujan Auditorium

IMSc Chennai

Speaker

Purusottam Ghosh (IMSc Chennai)

Description

The precise measurement of $N_{\rm eff}$ at the time of cosmic microwave background (CMB) formation by Planck (2018) can be used to understand the new fundamental interactions, in particular those involving light mediators. In this talk, I will discuss the impact of light gauge bosons (order of MeV) originating from various types of $U(1)_X$​ on the $N_{\rm eff}$. In the low-mass region, the bound on $N_{\rm eff}$​ at CMB is more stringent than current experimental constraints.

Presentation materials