234 research outputs found

    Charged Higgs-boson pair production in association with the Z0Z^0 boson at electron-positron colliders

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    In this paper, the production of the charged Higgs pair associated with the Z0Z^0 boson is analyzed in the minimal extension of the standard model the so-called two-Higgs-doublet model (2HDM). The process e+eH+HZ0e^+e^- \rightarrow H^+H^-Z^0 is calculated at the tree level including all the possible diagrams in 2HDM. The numerical analysis is performed in consideration of the current experimental constraints and various scenarios for the free parameters of the model. The results are presented as a function of center-of-mass energy, the charged Higgs mass (mH±m_{H^\pm}), and the ratio of the vacuum expectation values (tβt_\beta). The unpolarized cross section, taking into account the results in the flavor physics, gets up to 0.278 fb0.278\text{ fb} for mH±=175 GeVm_{H^\pm}=175\text{ GeV}, and it declines with decreasing mH±m_{H^\pm} in Type-I. However, it gets down to 0.073 fb0.073\text{ fb} for mH±=500 GeVm_{H^\pm}=500\text{ GeV} in Type-II. Further, the calculation is also carried out in the non-alignment scenario and low-mh0m_{h^0} scenario. The effect of the polarized incoming e+e^+ and ee^- beams shows that the cross section is enhanced by a factor up to 2.5 at P(+0.60,-0.80) polarization configuration. Decay channels of the charged Higgs, possible final states of the process, and some differential distributions belong to the charged Higgs and Z0Z^0 boson are examined for each scenario. The analysis shows that some channels have higher branching ratio such as H+tbˉH^+\rightarrow t \bar{b}, H+W+h0H^+\rightarrow W^+h^0, and H+W+H0H^+\rightarrow W^+H^0. These decay channels are essential for the charged Higgs searches in the lepton colliders regarding the scenarios interested. The detection of the charged Higgs is a powerful sign for the extended scalar sectors, and the results show the potential of a future lepton collider.Comment: 29 pages, 12 figure

    Neutralino Pair Production at the Photon-Photon Collider for the τ~\tilde{\tau}-Coannihilation Scenario

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    Supersymmetry (SUSY) is a theory that gives an explanation for the strong and electroweak interactions from the grand unification scale down to the weak scale. The search for supersymmetric particles still continues at full speed at the LHC without success. The main tasks at the ILC is complementing the LHC result and also search for new physics. In this study, the neutralino pair production via photon-photon collision is studied for the t~\tilde{t}-coannihilation scenario in the context of MSSM at the ILC. In the calculation, all the possible one-loop diagrams are taken into account for the photon-photon interaction. We present the production cross section and distribution of various observables for the lightest and next-to-lightest neutralino pairs for benchmark models which are specifically presented in the light of LHC8 data analysis, employing these benchmark models for neutralino pair production could show the potential of the ILC concerning the dark matter searches in supersymmetry.Comment: 5 pages, 4 figure

    Investigation of Neutralino Pair Production in Photon-Photon Collider at ILC

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    Neutralino pair production via photon-photon collisions is analyzed in the context of Minimal Supersymmetric Standard Model at future linear collider. Since photon does not have self coupling, this process is only possible at Next-to-Leading order and all the possible terms are calculated for the photon-photon interaction, including box, triangles and quartic coupling diagrams. Numerical analysis of the production rates for χ~10χ~10 \tilde{\chi}^0_1 \tilde{\chi}^0_1, χ~10χ~20 \tilde{\chi}^0_1 \tilde{\chi}^0_2 and χ~20χ~20 \tilde{\chi}^0_2 \tilde{\chi}^0_2 are presented for four new distinct benchmark models which are presented in the light of LHC8. Angular dependence of each neutralino pairs for the benchmark points are also presented. Total integrated photonic cross section goes up to 1.23  fb1.23\;fb and 1.26  fb1.26\;fb for the χ~10χ~10 \tilde{\chi}^0_1 \tilde{\chi}^0_1 and χ~20χ~20 \tilde{\chi}^0_2 \tilde{\chi}^0_2 pairs, respectively for the Radiatively driven natural susy benchmark point.Comment: 19 pages, 12 figure

    Pair production of the lightest chargino at γγ\gamma\gamma-collider

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    Chargino pair production via photon-photon collision is investigated in the Minimal Supersymmetric Standard Model at a future linear collider. The process is computed using all the possible diagrams at the next-to-leading order, including box, triangle, and self-energy diagrams. The numerical analysis is carried out for the production rates of the lightest chargino pair in RNS, NS, mSUGRA, BB, and NUGM scenarios. These distinct benchmark models were introduced in the light of the LHC results presented at s=78 TeV\sqrt{s}=7-8\text{ TeV}. Among these scenarios, the RNS has the highest production rate for the γγχ~1+χ~1\gamma\gamma\rightarrow \tilde\chi_1^+ \tilde\chi_1^-. The partonic cross section reaches up to 3.94 pb3.94\text{ pb} at s^=310 GeV\sqrt{\hat{s}}=310\text{ GeV}. The total convoluted cross section with the photon luminosity in a e+ee^+e^- machine is calculated as a function of the center-of-mass energy up to 1 TeV1\text{ TeV}. The convoluted cross section is 1.05 pb\sim1.05\text{ pb} at s=350 GeV\sqrt{s}=350\text{ GeV} depending on the polarization of the initial electron and laser polarization. The RNS along with the BB scenarios are accessible at s=500 GeV\sqrt{s}=500\text{ GeV} with a γγ\gamma\gamma collision mode on e+ee^+e^--collider.Comment: 14 pages, 12 figure

    Radiation-Hardness Measurements of High OHOH^{-} Content Quartz Fibres Irradiated with 24 GeV Protons up to 1.25 Grad

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    We investigated the darkening of two high OH- content quartz fibres irradiated with 24 GeV protons at the Cern PS facility IRRAD. The two tested fibres have a 0.6 mm quartz core diameter, one with hard plastic cladding (qp) and the other with quartz cladding (qq). These fibres were exposed at about 1.25 Gigarad in 3 weeks. The fibres became opaque below 380nm, and in the range 580-650 nm. The darkening under irradiation and damage recovery after irradiation as a function of dose and time are similar to what we observed with electrons. The typical attenuation at 455 nm are 1.44 + - 0.22 and 2.20 + - 0.15 dB/m at 100 Mrad for qp and qq fibres, respectively. The maximum damage recovery is also observed near this wavelength

    Design, Performance, and Calibration of the CMS Hadron-Outer Calorimeter

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    The CMS hadron calorimeter is a sampling calorimeter with brass absorber and plastic scintillator tiles with wavelength shifting fibres for carrying the light to the readout device. The barrel hadron calorimeter is complemented with an outer calorimeter to ensure high energy shower containment in the calorimeter. Fabrication, testing and calibration of the outer hadron calorimeter are carried out keeping in mind its importance in the energy measurement of jets in view of linearity and resolution. It will provide a net improvement in missing \et measurements at LHC energies. The outer hadron calorimeter will also be used for the muon trigger in coincidence with other muon chambers in CMS

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation