Abstract
In the next-to-minimal supersymmetric Standard Model (NMSSM) with extra heavy neutrino superfields, a neutrino may acquire its mass via a seesaw mechanism and sneutrino may act as a viable dark matter (DM) candidate. Given the strong tension between the naturalness for $Z$ boson mass and the DM direct detection experiments for customary neutralino DM candidate, we augment the NMSSM with type-I seesaw mechanism, which is the simplest extension of the theory to predict neutrino mass, and study the scenarios of sneutrino DM. We construct a likelihood function with LHC Higgs data, B-physics measurements, DM relic density and its direct and indirect search limits, and perform a comprehensive scan over the parameter space of the theory by the nested sampling method. We adopt both Bayesian and frequentist statistical quantities to illustrate the favored parameter space of the scenarios, the DM annihilation mechanism as well as the features of DM-nucleon scattering. We find that the scenarios are viable over broad parameter regions, especially the Higgsino mass $\ensuremath{\mu}$ can be below about 250 GeV for a significant part of the region, which predicts $Z$ boson mass in a natural way. We also find that the DM usually coannihilated with the Higgsinos to get the measured relic density, and consequently the DM-nucleon scattering rate is naturally suppressed to coincide with the recent XENON-1T results even for light Higgsinos. Other issues, such as the LHC search for the Higgsinos, are also addressed.
Highlights
A large number of cosmological and astrophysical observations have firmly established the existence of nonbaryonic dark matter (DM) [1,2,3,4]
Given the strong tension between the naturalness for Z boson mass and the DM direct detection experiments for customary neutralino DM candidate, we augment the next-to-minimal supersymmetric Standard Model (NMSSM) with type-I seesaw mechanism, which is the simplest extension of the theory to predict neutrino mass, and study the scenarios of sneutrino DM
SM-like Higgs boson is much larger than that with the lightest Higgs boson h2 as the SM-like Higgs boson [40,41], we focus on the scenario where h1 corresponds to the Higgs boson discovered at the LHC, and present the results according to the CP property of the sneutrino DM ν1. (ii) For the second, third, and fourth contributions, i.e., the likelihood functions about the measurements of BrðBs → μþμ−Þ, BrðBs → XsγÞ and DM relic density Ων1, they are Gaussian distributed, i.e., L 1⁄4 e ; −1⁄2Oth where Oth denotes the theoretical prediction of the observable O, Oexp represents its experimental central value and σ is the total uncertainty
Summary
A large number of cosmological and astrophysical observations have firmly established the existence of nonbaryonic dark matter (DM) [1,2,3,4]. Group, the scalar component fields of νR, Xand Scompose a secluded DM sector, which can account for the measured DM relic abundance, and be testable by future DM indirect detect experiments and LHC experiments Since this sector communicates with the SM sector mainly through the small singlet-doublet Higgs mixing, the DM-nucleon scattering rate is naturally suppressed, which is consistent with current DM direct search results. We note that these features should be applied to the type-I seesaw extension of the NMSSM due to the similarities of the two theoretical frameworks..
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