DPF - PHENO 2024

Cosmological implications of gauged U(1)B−L on ΔNeff in the CMB and BBN

14 May 2024, 17:15

15m

Barco Law Building 107 (University of Pittsburgh)

Cosmology & Dark Energy Cosmology & Dark Energy

Speaker

Haidar Esseili (University of Oregon)

Description

We calculate the effects of a light, very weakly-coupled boson $X$ arising from a spontaneously broken $U(1{)}_{B-L}$ symmetry on $\mathrm{\Delta }{N}_{\mathrm{e}\mathrm{f}\mathrm{f}}$ as measured by the CMB and $Y_p$ from BBN. Our focus is the mass range $1\mathrm{e}\mathrm{V}\lesssim m_X\lesssim 100\mathrm{M}\mathrm{e}\mathrm{V}$. We find $U(1{)}_{B-L}$ is more strongly constrained by $\mathrm{\Delta }{N}_{\mathrm{e}\mathrm{f}\mathrm{f}}$ than previously considered. While some of the parameter space has complementary constraints from stellar cooling, supernova emission, and terrestrial experiments, we find future CMB observatories including Simons Observatory and CMB-S4 can access regions of mass and coupling space not probed by any other method.

Presentation materials

HaidarEsseili_Pheno.pdf