119114407
Exploring the Higgs sector of a most natural NMSSM and its prediction on Higgs pair production at the LHC
A bstractAs a most natural realization of the Next-to Minimal Supersymmetry Standard Model (NMSSM), λ-SUSY is parameterized by a large λ around one and a low tan β below 10. In this work, we first scan the parameter space of λ-SUSY by considering various experimental constraints, including the limitation from the Higgs data updated by the ATLAS and CMS collaborations in the summer of 2014, then we study the properties of the Higgs bosons. We get two characteristic features of λ-SUSY in experimentally allowed parameter space. One is the triple self coupling of the SM-like Higgs boson may get enhanced by a factor over 10 in comparison with its SM prediction. The other is the pair production of the SM-like Higgs boson at the LHC may be two orders larger than its SM prediction. All these features seems to be unachievable in the Minimal Supersymmetric Standard Model and in the NMSSM with a low λ. Moreover, we also find that naturalness plays an important role in selecting the parameter space of λ-SUSY, and that the Higgs χ2 obtained with the latest data is usually significantly smaller than before due to the more consistency of the two collaboration measurements.
53520209
Pair production of 125 GeV Higgs boson in the SM extension with color-octet scalars at the LHC
A bstractAlthough the Higgs boson mass and single production rate have been determined more or less precisely, its other properties may deviate significantly from its predictions in the standard model (SM) due to the uncertainty of Higgs data. In this work we study the Higgs pair production at the LHC in the Manohar-Wise model, which extends the SM by one family of color-octet and isospin-doublet scalars. We first scanned over the parameter space of the Manohar-Wise model considering experimental constraints and performed fits in the model to the latest Higgs data by using the ATLAS and CMS data separately. Then we calculated the Higgs pair production rate and investigated the potential of its discovery at the LHC14. We conclude that: (i) Under current constrains including Higgs data after Run I of the LHC, the cross section of Higgs pair production in the Manohar-Wise model can be enhanced up to even 103 times prediction in the SM. (ii) Moreover, the sizable enhancement comes from the contributions of the CP-odd color-octet scalar $ S_I^A $. For lighter scalar $ S_I^A $ and larger values of |λI|, the cross section of Higgs pair production can be much larger. (iii) After running again of LHC at 14 TeV, most of the parameter spaces in the Manohar-Wise model can be test. For an integrated luminosity of 100 fb−1 at the LHC14, when the normalized ratio R = 10, the process of Higgs pair production can be detected.
119120163
Current experimental bounds on stop mass in natural SUSY
A bstractMotivated by the recent progress of direct search for the productions of stop pair and sbottom pair at the LHC, we examine the constraints of the search results on the stop ($ \widetilde{t} $1) mass in natural SUSY. We first scan the parameter space of natural SUSY in the framework of MSSM, considering the constraints from the Higgs mass, B-physics and electroweak precision measurements. Then in the allowed parameter space we perform a Monte Carlo simulation for stop pair production followed by $ \widetilde{t} $1 → t$ \widetilde{\chi}_1^0 $ or $ \widetilde{t} $1 → b$ \widetilde{\chi}_1^{+} $ and sbottom pair production followed by $ \widetilde{b} $1 → b$ \widetilde{\chi}_1^0 $ or $ \widetilde{b} $1 → t$ \widetilde{\chi}\overline{1} $. Using the combined results of ATLAS with 20.1 fb−1 from the search of ℓ + jets + T , hadronic $ t\overline{t} $ + T and 2b + T , we find that a stop lighter than 600 GeV can be excluded at 95% CL in this scenario.
119251817
Modified holographic Ricci dark energy coupled to interacting relativistic and non-relativistic dark matter in the nonflat universe
The modified holographic Ricci dark energy coupled to interacting relativistic and non-relativistic dark matter is considered in the nonflat Friedmann-Robertson-Walker universe. Through examining the deceleration parameter, one can find that the transition time of the Universe from decelerating to accelerating phase in the interacting holographic Ricci dark energy model is close to that in the $\Lambda$ cold dark matter model. The evolution of modified holographic Ricci dark energy's state parameter and the evolution of dark matter and dark energy's densities shows that the dark energy holds the dominant position from the near past to the future. By studying the statefinder diagnostic and the evolution of the total pressure, one can find that this model could explain the Universe's transition from the radiation to accelerating expansion stage through the dust stage. According to the $Om$ diagnostic, it is easy to find that when the interaction is weak and the proportion of relativistic dark matter in total dark matter is small, this model is phantom-like. Through our studying, we find the interaction and the relativistic dark matter's proportion all have great influence on the evolution of the Universe.
119118634
Quasi-exactly solvable models derived from the quasi-Gaudin algebra
The quasi-Gaudin algebra was introduced to construct integrable systems which are only quasi-exactly solvable. Using a suitable representation of the quasi-Gaudin algebra, we obtain a class of bosonic models which exhibit this curious property. These models have the notable feature that they do not preserve U(1) symmetry, which is typically associated with a non-conservation of particle number. An exact solution for the eigenvalues within the quasi-exactly solvable sector is obtained via the algebraic Bethe ansatz formalism.
11648919
Complementarity of LHC and EDMs for exploring Higgs CP violation
A bstractWe analyze the constraints on a CP-violating, flavor conserving, two Higgs doublet model from the measurements of Higgs properties and from the search for heavy Higgs bosons at LHC, and show that the stronger limits typically come from the heavy Higgs search channels. The limits on CP violation arising from the Higgs sector measurements are complementary to those from EDM measurements. Combining all current constraints from low energy to colliders, we set generic upper bounds on the CP violating angle which parametrizes the CP odd component in the 126 GeV Higgs boson.
18230581
Supersymmetric extension of the sine-Gordon theory with integrable boundary interactions
Integrability and supersymmetry of the supersymmetric extension of the sine-Gordon theory on a half-line are examined and the boundary potential which preserves both the integrability and supersymmetry on the bulk is derived. It appears that unlike the boundary bosonic sine-Gordon theory, integrability and supersymmetry strongly restrict the form and parameters of the boundary potential, so that no free parameter in the boundary term is allowed up to a choice of signs.
119308558
Vacuum stability and Higgs diphoton decay rate in the Zee-Babu model
A bstractAlthough recent Higgs data from ATLAS and CMS are compatible with a Standard Model (SM) signal at 2σ level, both experiments see indications for an excess in the diphoton decay channel, which points to new physics beyond the SM. Given such a low Higgs mass mH ~ 125 GeV, another sign indicating the existence of new physics beyond the SM is the vacuum stability problem, i.e., the SM Higgs quartic coupling may run to negative values at a scale below the Planck scale. In this paper, we study the vacuum stability and enhanced Higgs diphoton decay rate in the Zee-Babu model, which was used to generate tiny Majorana neutrino masses at two-loop level. We find that it is rather difficult to find overlapping regions allowed by the vacuum stability and diphoton enhancement constraints. As a consequence, it is almost inevitable to introduce new ingredients into the model, in order to resolve these two issues simultaneously.