XXV DAE-BRNS High Energy Physics Symposium 2022

Secluded Dark Sector and Muon (g−2) in the Light of Fast Expanding Universe

16 Dec 2022, 14:00

1h

LHC Foyer (IISER Mohali)

Poster Poster - 4

Speaker

Ananya Tapadar (Indian Association for the Cultivation of Science)

Description

The lack of information before Big Bang Neucleosynthesis (BBN) allow us to assume the presence of a new species $\varphi$ whose energy density redshifts as $a^{-(4+n)}$ where $n>0$ and $a$ is the scale factor. In this non-standard cosmological setup, we have considered $U(1{)}_{L_{\mu }-L_{\tau }}$ $\otimes U(1{)}_X$ gauge extension of the Standard Model (SM) and studied different phases of the cosmological evolution of a thermally decoupled dark sector such as leak-in, freeze-in, reannihilation, and late-time annihilation. This non-standard cosmological setup facilitates a larger portal coupling $(ϵ)$ between the dark and the visible sectors even when the two sectors are not in thermal equilibrium. The dark sector couples with the $\mu$ and $\tau$ flavored leptons of the SM due to the tree level kinetic mixing between $U(1{)}_X$ and $U(1{)}_{L_{\mu }-L_{\tau }}$ gauge bosons. We show that in our scenario it is possible to reconcile the dark matter relic density and muon $(g-2)$ anomaly. In particular, we show that for $3\times {10}^{-4}\lesssim ϵ\lesssim {10}^{-3}$, $30\mathrm{M}\mathrm{e}\mathrm{V}\lesssim m_{Z^{\prime }}\lesssim 300\mathrm{M}\mathrm{e}\mathrm{V}$, $n=4$, and $1\mathrm{T}\mathrm{e}\mathrm{V}\lesssim m_{\chi }\lesssim 10\mathrm{T}\mathrm{e}\mathrm{V}$ relic density constraint of dark matter, constraint from muon $(g-2)$ anomaly, and other cosmological, astrophysical constraints are satisfied.