Natural NMSSM after LHC Run I and the Higgsino dominated dark matter scenario

Abstract

Abstract:We investigate the impact of the direct searches for SUSY at LHC Run I on the naturalness of the Next-to-Minimal Supersymmetric Standard Model (NMSSM). For this end, we first scan the vast parameter space of the NMSSM to get the region where the fine tuning measures ∆ Z and ∆ h at the electroweak scale are less than about 50, then we implement by simulations the constraints of the direct searches on the parameter points in the region. Our results indicate that although the direct search experiments are effective in excluding the points, the parameter intervals for the region and also the minimum reaches of ∆ Z and ∆ h are scarcely changed by the constraints, which implies that the fine tuning of the NMSSM does not get worse after LHC Run I. Moreover, based on the results we propose a natural NMSSM scenario where the lightest neutralinoχ 0 1 as the dark matter (DM) candidate is Higgsino-dominated. In this scenario, ∆ Z and ∆ h may be as low as 2 without conflicting with any experimental constraints, and intriguinglyχ 0 1 can easily reach the measured DM relic density due to its significant Singlino component. We exhibit the features of the scenario which distinguish it from the other natural SUSY scenario, including the properties of its neutralino-chargino sector and scalar top quark sector. We emphasize that the scenario can be tested either through searching for 3l + E miss T signal at 14 TeV LHC or through future DM direct detection experiments.

Current status of a natural NMSSM in light of LHC 13 TeV data and XENON-1T results

“…While for the samples with h 1 corresponding to the SM-like Higgs boson, they satisfy µ 450GeV with µ m χ 0 1 or m m χ 0 1 . These features entail following conditions for the samples to be consistent with the experimental constraints: moderately strong cancellation between the h 1 and h 2 contributions to the SI cross section, |N 13 | 2 |N 14 | 2 as well as the suppressed spectrum of the sparticles with χ 0 1 [54,57] 3 .…”

“…We checked the properties of these samples and found that they have been excluded by the 3 + E miss T search at the LHC [102]. [54]. We checked that the main annihilation channels of the DM in early universe include χ 0…”

“…These studies indicate that, although the experiments are very effective in excluding the parameter points of the scenario, ∆ Z and ∆ h may still be as low as 2, and the property of the DM candidate is diverse, e.g. it may be either Bino-, Singlino-or Higgsino-dominated [54]. This situation, however, may be changed greatly since experimental search for the production of SUSY particles at LHC and DM-nucleon scattering in DM direct detection experiments has made considerable progress in the last years, which was emphasized in recent works [64,65].…”

Constraining resonant dark matter with combined LHC electroweakino searches

“…On the theoretical side, Z/h resonant annihilation is important in natural SUSY [37], especially in the natural MSSM, since it allows the lightest neutralino to achieve the observed thermal relic density [38]. In the natural Next-to-MSSM (NMSSM), although the inclusion of a singlet superfield relaxes the experimental constraints on the electroweakinos, the exclusion of the Z/h funnel region increases the lower limit on the DM mass from 20 GeV to 80 GeV [39][40][41]. The lower limit on the DM mass, in turn, is critical for any LHC sparticle search because under R-parity all sparticles decay to the lightest supersymmetric particle (LSP)χ 0 1 and the LSP mass is folded into the analyses.…”

The current status of fine-tuning in supersymmetry

“…Refs. [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67]). In this paper, we reanalyze the question: does the non-observation of SUSY particles make any minimal realization of a supersymmetric SM necessarily an unnatural theory?…”