Author:
Lu Zhiyu,Imtiaz Batool,Zhang Dongdong,Cai Yi-Fu
Abstract
AbstractWe are studying the effects of Self-Interacting dark radiation (SIdr) on the evolution of the universe. Our main focus is on the cosmic microwave background (CMB) and how SIdr could potentially help resolve the Hubble tension. We are looking into different scenarios by mixing SIdr with Free-Streaming dark radiation (FSdr) or not to determine whether SIdr can indeed contribute to solving the Hubble tension. We find that SIdr alone can increase the Hubble constant ($$H_0$$
H
0
) to $$70.1_{-1.6}^{+1.3}, \text {km/s/Mpc}$$
70
.
1
-
1.6
+
1.3
,
km/s/Mpc
with a value of $$N_\textrm{eff}=3.27_{-0.31}^{+0.23}$$
N
eff
=
3
.
27
-
0.31
+
0.23
. However, including FSdr disfavors the existence of SIdr $${\tilde{N}}_\textrm{si}\approx 0.37$$
N
~
si
≈
0.37
. Even though the Hubble constant is increased compared to the predicted value, it entails $$N_\textrm{eff}=3.52\pm 0.25$$
N
eff
=
3.52
±
0.25
. Finally, we implement the Fisher method for future experiments and a $$7.64\sigma $$
7.64
σ
measurement of $${\tilde{N}}_\textrm{si}$$
N
~
si
will be obtained when combing data from Planck, AliCPT, and CMB-S4.
Funder
CAS project for young scientists in basic research
National Natural Science Foundation of China
Observational and Theoretical Research on Dark Matter and Dark Energy
National Key Research and Development Program of China
CAS Young Interdisciplinary Innovation Team
Publisher
Springer Science and Business Media LLC