No Arabic abstract
We examine the sensitivity of the angular distribution of the Higgs boson in the process of $e^+e^-to Z H$ and the total cross section in the minimal noncommutative standard model (mNCSM) framework to set lower limit on the noncommutative charactristic scale ($Lambda$). Contrary to the standard model case, in this process the Higgs boson tends to be emitted anisotropically in the transverse plane. Based on this fact, the profile likelihood ratio is used to set lower limit on $Lambda$. The lower limit is presented as a function of the integrated luminosity. We show that at the center-of-mass energy of 1.5 TeV and with 500 fb$^{-1}$ of data, the noncommutative characteristic energy scale $Lambda$ can be excluded up to 1.2 TeV.
We calculate the cross sections for the production of Higgs particles in association with a photon in $e^+ e^-$ collisions, $e^+ e^- to gamma+$Higgs, allowing for the longitudinal polarization of the initial electron and positron beams. We consider the associated production of both the Standard Model Higgs boson, and the neutral CP-even and CP-odd Higgs particles of its minimal supersymmetric extension. Complete and compact analytical expressions are given, and the size of the cross sections is illustrated for energies which will be reached at future $e^+ e^-$ colliders.
We present the first complete 1-loop diagrammatic calculation of the cross sections for the neutral Higgs production processes $e^+e^-ra Z^0h^0$ and $e^+e^-ra A^0h^0$ in the minimal supersymmetric standard model. We compare the results from the diagrammatic calculation with the corresponding ones of the simpler and compact effective potential approximation and discuss the typical size of the differences.
The littlest Higgs model is the most economical one among various little Higgs models. In the context of the littlest Higgs(LH) model, we study the process $e^{-}gammato u_{e}W^{-}H$ and calculate the contributions of the LH model to the cross section of this process. The results show that, in most of parameter spaces preferred by the electroweak precision data, the value of the relative correction is larger than 10%. Such correction to the process $e^{-}gammato u_{e}W^{-}H$ is large enough to be detected via $e^{-}gamma$ collisions in the future high energy linear $e^{+}e^{-}$ collider($LC$) experiment with the c.m energy $sqrt{s}$=500 GeV and a yearly integrated luminosity $pounds=100fb^{-1}$, which will give an ideal way to test the model.
For the search for additional Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM) as well as for future precision analyses in the Higgs sector a precise knowledge of their production properties is mandatory. We review the evaluation of the cross sections for the neutral Higgs boson production in association with a photon at future $e^+e^-$ colliders in the MSSM with complex parameters (cMSSM). The evaluation is based on a full one-loop calculation of the production mechanism $e^+e^- to h_i gamma$ ($i = 1,2,3$). The dependence of the lightest Higgs-boson production cross sections on the relevant cMSSM parameters is analyzed numerically. We find relatively small numerical depedences of the production cross sections on the underlying parameters.
We present a comprehensive analysis of hadron production in e+e- collisions at different center-of-mass energies in the framework of the statistical model of the hadron resonance gas. The model is formulated in the canonical ensemble with exact conservation of all relevant quantum numbers. The parameters of the underlying model were determined using a fit to the average multiplicities of the latest measurements at $sqrt{s}$ = 10, 29-35, 91 and 130-200 GeV. The results demonstrate that, within the accuracy of the experiments, none of the data sets is satisfactorily described with this approach, calling into question the notion that particle production in e+e- collisions is thermal in origin.