584 research outputs found
Gravitational Waves Produced by Domain Walls During Inflation
We study the properties of the stochastic gravitational wave background
(SGWB) produced by domain walls (DWs) during inflation without forming a
network. We numerically simulate the DW production caused by a second-order
phase transition and calculate the SGWB spectrum using a
lattice. We show that the SGWB can be observed
directly by future terrestrial and spatial gravitational wave detectors and
through the B-mode spectrum in CMB. This signal can also explain the common
noise process observed by pulsar timing array experiments. With numerical
simulations, we derive an empirical formula for the strength and qualitative
features of the SGWB spectrum. The details of the SGWB spectrum also contain
information about the later evolution of the universe.Comment: 5 pages, 7 figures + appendi
Direct detection of freeze-in inelastic dark matter
We show that the current sensitivities of direct detection experiments have
already reached the interesting parameter space of freeze-in dark matter models
if the dark sector is in the inelastic dark matter framework and the excited
dark matter state is cosmologically stable. Using results recently presented by
the XENON1T experiment, we present constraints on these models. We also show
that these models can explain the reported excess in the electron recoil
signals if the mass gap between the ground state and the excited state is at
keV scale.Comment: 7 pages, 7 figure
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