Phenomenology Study Of A 125 GeV Higgs Boson In MSSM And MDM

Since the establishment of the standard model(SM)in particle physics, physicists have been devoting themselves to testing the correctness of the SM through a lot of experiments. For decades, with the accumulation of experimental data, most predictions of the SM have been confirmed. So far, it is deemed that the SM is one of the best theories in describing the microscopic particle world. However, the standard model is not perfect and there are still many problems, such as the fine tuning problem, the unity of four basic interactions, and so on. In order to solving these problems, some physicists have tried to extend the standard model and established a lot of new physical models. And the SM is just treated as a low-energy effective theory of some new physical models.Due to the special role of Higgs particles in these theories, the phenomenological study of its properties is one of the most important topics in particle physics nowadays. In July 2012,both the ATLAS and CMS collaborations at the LHC announced the discovery of a new scalar with mass around 125 Ge V, which coincides with those of the Higgs boson predicted by SM.Nevertheless, the issue of whether this particle is the SM Higgs boson is still open. Therefore, the phenomenological study of Higgs physics is only just beginning and the precise measurements of its properties will be a key for distinguishing different new physical models.In this thesis, we perform a phenomenological study on the Higgs boson in the minimal supersymmetric standard model(MSSM) and the minimal Dilaton model(MDM). The contents are summarized as follows:In the MSSM, We investigate the one-loop contributions to the mass of SM-like Higgs boson considering the effect of slepton flavor mixing, which is parametrized by the dimensionless parameter (, = , ) in the slepton mass matrices. For the surviving samples under the experimental constraints, we calculate the corrections to the mass of SM-like Higgs boson in terms of . We find that the mass correction Δ?can even be larger than 10 Ge V for large or . Moreover, Δ?has strong sensitivity to or ,while the weak sensitivity to or , since or enter directly into the coupling of Higgs boson with sleptons in the calculations of Higgs boson self-energies.In the MDM, we investigate the ′-induced radiative correction to the Higgs-strahlung production process +-â†' ? at future Higgs factory. We first present the analytical calculations in detail and show how to handle the ultraviolet divergence. Then we calculate the correction numerically by considering the constraints from precision electroweak data.We note that such a correction is able to be probed at the TLEP. And we find that, for sin = 0.2 and ′= 1200 Ge V, the correction is 0.26% and 2.1% for√+-= 240 Ge V, 1Te V respectively, and a larger value can be achieved as sin increases.