The Higgs Portal Above Threshold

Craig, Nathaniel; Thalapillil, Arun; Lou, Hou Keong; McCullough, Matthew

doi:10.1007/JHEP02(2016)127

Article
Report number	arXiv:1412.0258
Title	The Higgs Portal Above Threshold
Author(s)	Craig, Nathaniel (UC, Santa Barbara) ; Lou, Hou Keong (Princeton U.) ; McCullough, Matthew (CERN) ; Thalapillil, Arun (Rutgers U., Piscataway)
Publication	2016-02-18
Imprint	30 Nov 2014
Number of pages	25
Note	25 pages, 10 figures. v2: Figures and references added, factors of 2 corrected; conclusions unchanged
In:	JHEP 02 (2016) 127
DOI	10.1007/JHEP02(2016)127
Subject category	Particle Physics - Phenomenology
Abstract	The discovery of the Higgs boson opens the door to new physics interacting via the Higgs Portal, including motivated scenarios relating to baryogenesis, dark matter, and electroweak naturalness. We systematically explore the collider signatures of singlet scalars produced via the Higgs Portal at the 14 TeV LHC and a prospective 100 TeV hadron collider. We focus on the challenging regime where the scalars are too heavy to be produced in the decays of an on-shell Higgs boson, and instead are produced primarily via an off-shell Higgs. Assuming these scalars escape the detector, promising channels include missing energy in association with vector boson fusion, monojets, and top pairs. We forecast the sensitivity of searches in these channels at $\sqrt{s} = 14$ & 100 TeV and compare collider reach to the motivated parameter space of singlet-assisted electroweak baryogenesis, Higgs Portal dark matter, and neutral naturalness.
Copyright/License	arXiv nonexclusive-distrib. 1.0 publication: © 2016-2025 The Author(s) (License: CC-BY-4.0), sponsored by SCOAP³

$Values of $v_c/T_c$ as a function of $m_\phi$ and $c_\phi$ for singlet-assisted electroweak baryogenesis. The shaded purple region indicates a runaway for the Higgs Portal model corresponding to $M^2 < 0$, but the runaway can be stabilized by adding a quartic coupling of the form $\lambda \phi^4$. A perturbative two-step phase transition may then proceed in a $\sim 50$ GeV-wide penumbra at the edge of the shaded purple region, while a two-step transition deeper in the purple region cannot be ruled out but requires nonperturbatively large values of $\lambda$ to ensure the EWSB vacuum is deeper than the singlet vacuum \cite{Curtin:2014jma}.$ $Contours of relic DM density from freeze-out through the Higgs Portal. Constraints on the parameter space from the LUX direct detection experiment \cite{Akerib:2013tjd} are shown in dotdashed red (labelled $\text{LUX}_{\text{NT}}$) where an additional assumption is made that in regions where thermal freeze-out over- or under-produces DM, additional fields and couplings lead to late-time DM dilution or production to realize the observed density. On the other hand, the solid red line (labelled $\text{LUX}_{\text{TH}}$) and shaded region show the parameter space which is excluded if one only takes the Lagrangian of \Eq{eq:portal} and the assumption of a standard thermal history. In this case $\Omega_\phi \propto c_\phi^{-2}$ and $\sigma_n \propto c_\phi^{2}$ thus the exclusion is almost independent of the coupling, and largely depends only on the mass.$ $The DM-nucleon scattering cross section weighted by the fractional relic density predicted by a standard thermal history $R_{DD} = \sigma_n \times \rho_{TH}/\rho_0$ as a function of the Higgs portal coupling $c_\phi$ for a variety of masses from $100 \text{ GeV} < m_\phi < 500 \text{ GeV} $ in steps of $25$ GeV. Masses $m_\phi < 2 m_h$ are shown in solid black and $m_\phi > 2 m_h$ in dashed red. Regions where DM is over-produced are not shown. This demonstrates that direct detection predictions for the Higgs portal with a standard thermal history only depend very weakly on the coupling and exclusions stronger than $\sigma_n < \mathcal{O}(1 \times 10^{-45} \text{cm}^2)$ typically exclude the Higgs portal with a standard thermal history independent of the coupling. The suppression with large coupling is shown whenever the $\phi + \phi \to h + h$ starts to dominate when kinematically accessible.$ Show more plots

Corresponding record in: Inspire

Torna a la cerca

Registre creat el 2014-12-02, darrera modificació el 2022-08-10

Article from SCOAP3: