Status of the scalar singlet dark matter model

Abstract

One of the simplest viable models for dark matter is an additional neutral scalar, stabilised by a Z 2 symmetry. Using the GAMBIT package and combining results from four independent samplers, we present Bayesian and frequentist global fits of this model. We vary the singlet mass and coupling along with 13 nuisance parameters, including nuclear uncertainties relevant for direct detection, the local dark matter density, and selected quark masses and couplings. We include the dark matter relic density measured by Planck, direct searches with LUX, PandaX, SuperCDMS and XENON100, limits on invisible Higgs decays from the a cornellj@physics.mcgill.ca Large Hadron Collider, searches for high-energy neutrinos from dark matter annihilation in the Sun with IceCube, and searches for gamma rays from annihilation in dwarf galaxies with the Fermi-LAT. Viable solutions remain at couplings of order unity, for singlet masses between the Higgs mass and about 300 GeV, and at masses above ∼1 TeV. Only in the latter case can the scalar singlet constitute all of dark matter. Frequentist analysis shows that the low-mass resonance region, where the singlet is about half the mass of the Higgs, can also account for all of dark matter, and remains viable. However, Bayesian considerations show this region to be rather fine-tuned.

FlavBit: a GAMBIT module for computing flavour observables and likelihoods

“…Accommodating lepton flavour non-universality within the effective Hamiltonian framework of Eq. 2 requires splitting operators O ( ) 9 and O ( ) 10 into separate effective operators for different leptons. In the context of this expanded treatment, the so-called flavour anomalies in rare decays seem to form a coherent pattern, with a reduction of about 25% observed in the muonic C 9 Wilson coefficient relative to the SM prediction.…”

“…FlavBit takes into account all theoretical and experimental correlations between the different observables. The resulting likelihoods can be incorporated into the GAMBIT global likelihood to scan the parameter spaces of various models for new physics [4,[8][9][10][11], taking into account complementary constraints from direct production [12], dark matter searches [13], and SM and related precision measurements [14].…”

“…This implies that when averaging between B s andB s , some terms of the angular distributions (including P 5 ) vanish. The branching ratios of both B s → φμ + μ − and the related decay B + → K + μ + μ − are sensitive to BSM physics, mainly via the Wilson coefficients C ( ) 9 and C ( ) 10 . The measurement of the branching fraction of B s → φμ + μ − by the LHCb experiment [15] is also in tension with respect to SM predictions.…”

Multicomponent Dark Matter in Radiative Seesaw Models

“…The upper bounds on the cross section off the nucleon is obtained by LUX [102] and XENON1T [103]. In the cases of onecomponent DM system of a real or complex scalar boson, those experimental results give the strong constraint on the masses of those DM particles; the allowed DM mass region is ≃m h /2 and > ∼ 1 TeV [104][105][106]. In the model A with the multicomponent DM system, the constrains on the cross sections off the nucleon for χ and φ R are also relatively severe.…”

Spontaneous mirror left-right symmetry breaking for leptogenesis parametrized by Majorana neutrino mass matrix

“…This scalar can annihilate into the ordinary species through the Higgs portal interaction. This simple dark matter scenario has been studied in a lot of literatures [69][70][71][72][73][74][75][76][77][78][79][80][81][82].…”