Abstract
Several Pulsar Timing Array(PTA)Collaborations have recently provided strong evidence for a nHz Stochastic Gravitational-Wave Background(SGWB).Here we investigate the implications of a first-order phase transition occurring within the early Universe's dark quantum chromodynamics epoch,specifically within the framework of the mirror twin Higgs dark sector model.Our analysis indicates a distinguishable SGWB signal originating from this phase transition,which can explain the measurements obtained by PTAs.Remarkably,a significant portion of the parameter space for the SGWB signal also effectively resolves the existing tensions in both the H0 and S8 measurements in Cosmology.This intrigu-ing correlation suggests a possible common origin of these three phenomena for 0.2＜ΔNeff＜0.5,where the mirror dark matter component constitutes less than 30％of the total dark matter abundance.Next-generation CMB experiments such as CMB-S4 can test this parameter region.
基金项目
国家重点研发计划(2022YFF0503304)
国家重点研发计划(2022YFF0503301)
国家自然科学基金(11921003)
国家自然科学基金(12003069)
New Cornerstone Science Foundation through the XPLORER PRIZE()
中国科学院项目()
Entrepreneurship and Innovation Program of Jiangsu Province()
NETL
NSTL
万方数据