Cosmological beam dump: constraints on dark scalars mixed with the Higgs boson. (arXiv:1812.07585v1 [hep-ph])
<a href="http://arxiv.org/find/hep-ph/1/au:+Fradette_A/0/1/0/all/0/1">Anthony Fradette</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Pospelov_M/0/1/0/all/0/1">Maxim Pospelov</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Pradler_J/0/1/0/all/0/1">Josef Pradler</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Ritz_A/0/1/0/all/0/1">Adam Ritz</a>
Precision cosmology provides a sensitive probe of extremely weakly coupled
states due to thermal freeze-in production, with subsequent decays impacting
physics during well-tested cosmological epochs. We explore the cosmological
implications of the freeze-in production of a new scalar $S$ via the
super-renormalizable Higgs portal. If the mass of $S$ is at or below the
electroweak scale, peak freeze-in production occurs during the electroweak
epoch. We improve the calculation of the freeze-in abundance by including all
relevant QCD and electroweak production channels. The resulting abundance and
subsequent decay of $S$ is constrained by a combination of X-ray data, cosmic
microwave background anisotropies and spectral distortions, $N_{rm eff}$, and
the consistency of BBN with observations. These probes constrain technically
natural couplings for such scalars from $m_S sim$ keV all the way to $m_S sim
100$ GeV. The ensuing constraints are similar in spirit to typical beam bump
limits, but extend to much smaller couplings, down to mixing angles as small as
$theta_{Sh} sim 10^{-16}$, and to masses all the way to the electroweak
scale.
Precision cosmology provides a sensitive probe of extremely weakly coupled
states due to thermal freeze-in production, with subsequent decays impacting
physics during well-tested cosmological epochs. We explore the cosmological
implications of the freeze-in production of a new scalar $S$ via the
super-renormalizable Higgs portal. If the mass of $S$ is at or below the
electroweak scale, peak freeze-in production occurs during the electroweak
epoch. We improve the calculation of the freeze-in abundance by including all
relevant QCD and electroweak production channels. The resulting abundance and
subsequent decay of $S$ is constrained by a combination of X-ray data, cosmic
microwave background anisotropies and spectral distortions, $N_{rm eff}$, and
the consistency of BBN with observations. These probes constrain technically
natural couplings for such scalars from $m_S sim$ keV all the way to $m_S sim
100$ GeV. The ensuing constraints are similar in spirit to typical beam bump
limits, but extend to much smaller couplings, down to mixing angles as small as
$theta_{Sh} sim 10^{-16}$, and to masses all the way to the electroweak
scale.
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