No Arabic abstract
Natural Next-to-Minimal Supersymmetric Standard Model (nNMSSM) is featured by predicting one CP-even Higgs boson satisfying $m_{h_1} lesssim 120 ,{rm GeV}$ and Higgsinos lighter than about 300 GeV, and consequently the cross section for DM-nucleon scattering in this scenario is usually quite large. We study the diphoton signal of the light Higgs boson in nNMSSM by considering the tight constraints from the latest LUX and PandaX-II experiments, and we conclude that the optimal value of the signal rate at 8 TeV LHC is greatly reduced in comparison with earlier predictions. For example, previous studies indicated that the rate may exceed $120 ,{rm fb}$ for $m_{h_1} simeq 80 ,{rm GeV}$, while it is at most $25 ,{rm fb}$ if the lightest neutralino in the scenario is fully responsible for the measured DM relic density. We also investigate the case of $m_{h_1} simeq 98 ,{rm GeV}$ which is hinted by the excesses of the LEP analysis on $Z bar{b} b$ signal and the CMS analysis on the diphoton signal. We conclude that nNMSSM can explain simultaneously the excesses at $1sigma$ level without violating any known constraints.
We explore the detection possibility of light pseudoscalar Higgs boson in the next-to-minimal supersymmetric Standard Model(NMSSM) at the LHC with the center of mass energy, $sqrt{S}=13$ TeV. We focus on the parameter space which provides one of the Higgs boson as the SM-like with a mass of 125 GeV and some of the non-SM-like Higgs bosons can be light having suppressed couplings with fermions and gauge bosons due to their singlet nature. It is observed that for certain region of model parameter space, the singlet like light pseudoscalar can decay to di-photon($gammagamma$) channel with a substantial branching ratio. In this study, we consider this di-photon signal of light pseudoscalar Higgs boson producing it through the chargino-neutralino production and the subsequent decay of neutralino. We consider signal consisting of two photons plus missing energy along with a lepton from the chargino decay. Performing a detailed simulation of the signal and backgrounds including detector effects, we present results for a few benchmark points corresponding to the pseudoscalar Higgs boson mass in the range 60 -100 GeV. Our studies indicate that some of the benchmark points in the parameter space can be probed with a reasonable significance for 100 fb$^{-1}$ integrated luminosity. We also conclude that exploiting this channel it is possible to distinguish the NMSSM from the other supersymmetric models.
While the properties of the 125 GeV Higgs boson-like particle observed by the ATLAS and CMS collaborations are largely compatible with those predicted for the Standard Model state, significant deviations are present in some cases. We, therefore, test the viability of a Beyond the Standard Model scenario based on Supersymmetry, the CP-violating Next-to-Minimal Supersymmetric Standard Model, against the corresponding experimental observations. Namely, we identify possible model configurations in which one of its Higgs bosons is consistent with the LHC observation and evaluate the role of the explicit complex phases in both the mass and diphoton decay of such a Higgs boson. Through a detailed analysis of some benchmark points corresponding to each of these configurations, we highlight the impact of the CP-violating phases on the model predictions compared to the CP-conserving case.
The excess of events in the diphoton final state near 750 GeV observed by ATLAS and CMS can be explained within the NMSSM near the R-symmetry limit. Both scalars beyond the Standard Model Higgs boson have masses near 750 GeV, mix strongly, and share sizeable production cross sections in association with b-quarks as well as branching fractions into a pair of very light pseudoscalars. Pseudoscalars with a mass of ~ 210 MeV decay into collimated diphotons, whereas pseudoscalars with a mass of ~ 500-550 MeV can decay either into collimated diphotons or into three pi^0 resulting in collimated photon jets. Various such scenarios are discussed; the dominant constraints on the latter scenario originate from bounds on radiative Upsilon decays, but they allow for a signal cross section up to 6.7 fb times the acceptance for collimated multiphotons to pass as a single photon.
Physics beyond the Standard Model (SM) may manifest itself as small deviations from the SM predictions for Higgs signal strengths at 125 GeV. Then, a plausible and interesting possibility is that the Higgs sector is extended and at the weak scale there appears an additional Higgs boson weakly coupled to the SM sector. Combined with the LEP excess in $e^+e^-to Z(hto bbar b)$, the diphoton excess around 96 GeV recently reported by CMS may suggest such a possibility. We examine if those LEP and CMS excesses can be explained simultaneously by a singlet-like Higgs boson in the general next-to-minimal supersymmetric Standard Model (NMSSM). Higgs mixing in the NMSSM relies on the singlet coupling to the MSSM Higgs doublets and the higgsino mass parameter, and thus is subject to the constraints on these supersymmetric parameters. We find that the NMSSM can account for both the LEP and CMS excesses at 96 GeV while accommodating the observed 125 GeV SM-like Higgs boson. Interestingly, the required mixing angles constrain the heavy doublet Higgs boson to be heavier than about 500 GeV. We also show that the viable region of mixing parameter space is considerably modified if the higgsino mass parameter is around the weak scale, mainly because of the Higgs coupling to photons induced by the charged higgsinos.
In the next-to minimal supersymmetric standard model (NMSSM) one additional singlet-like Higgs boson with small couplings to standard model (SM) particles is introduced. Although the mass can be well below the discovered 125 GeV Higgs boson mass its small couplings may make a discovery at the LHC difficult. We use a novel scanning technique to efficiently scan the whole parameter space and determine the range of cross sections and branching ratios for the light singlet-like Higgs boson below 125 GeV. This allows to determine the perspectives for the future discovery potential at the LHC. Specific LHC benchmark points are selected representing the salient NMSSM features.