55 research outputs found

    Evaluation of measurement accuracies of the Higgs boson branching fractions in the International Linear Collider

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    Precise measurement of Higgs boson couplings is an important task for International Linear Collider (ILC) experiments and will facilitate the understanding of the particle mass generation mechanism. In this study, the measurement accuracies of the Higgs boson branching fractions to the bb and cc quarks and gluons, ΔBr(Hbbˉ,ccˉ,gg)/Br\Delta Br(H\to b\bar{b},\sim c\bar{c},\sim gg)/Br, were evaluated with the full International Large Detector model (\texttt{ILD\_00}) for the Higgs mass of 120 GeV at the center-of-mass (CM) energies of 250 and 350 GeV using neutrino, hadronic and leptonic channels and assuming an integrated luminosity of 250fb1250 {\rm fb^{-1}}, and an electron (positron) beam polarization of -80% (+30%). We obtained the following measurement accuracies of the Higgs cross section times branching fraction (Δ(σBr)/σBr\Delta (\sigma \cdot Br)/\sigma \cdot Br) for decay of the Higgs into bbˉb\bar{b}, ccˉc\bar{c}, and gggg; as 1.0%, 6.9%, and 8.5% at a CM energy of 250 GeV and 1.0%, 6.2%, and 7.3% at 350 GeV, respectively. After the measurement accuracy of the cross section (Δσ/σ\Delta\sigma/\sigma) was corrected using the results of studies at 250 GeV and their extrapolation to 350 GeV, the derived measurement accuracies of the branching fractions (ΔBr/Br\Delta Br/Br) to bbˉb\bar{b}, ccˉc\bar{c}, and gg were 2.7%, 7.3%, and 8.9% at a CM energy of 250 GeV and 3.6%, 7.2%, and 8.1% at 350 GeV, respectively.Comment: 15 pages, 6 figure

    TeV Scale Implications of Non Commutative Space time in Laboratory Frame with Polarized Beams

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    We analyze e+eγγe^{+}e^{-}\rightarrow \gamma\gamma, eγeγe^{-}\gamma \rightarrow e^{-}\gamma and γγe+e\gamma\gamma \rightarrow e^{+}e^{-} processes within the Seiberg-Witten expanded noncommutative scenario using polarized beams. With unpolarized beams the leading order effects of non commutativity starts from second order in non commutative(NC) parameter i.e. O(Θ2)O(\Theta^2), while with polarized beams these corrections appear at first order (O(Θ)O(\Theta)) in cross section. The corrections in Compton case can probe the magnetic component(ΘB\vec{\Theta}_B) while in Pair production and Pair annihilation probe the electric component(ΘE\vec{\Theta}_E) of NC parameter. We include the effects of earth rotation in our analysis. This study is done by investigating the effects of non commutativity on different time averaged cross section observables. The results which also depends on the position of the collider, can provide clear and distinct signatures of the model testable at the International Linear Collider(ILC).Comment: 22 pages, 19 figures, new comments and references added, few typos corrected, Published in JHE

    Neutrino-electron scattering in noncommutative space

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    Neutral particles can couple with the U(1)U(1) gauge field in the adjoint representation at the tree level if the space-time coordinates are noncommutative (NC). Considering neutrino-photon coupling in the NC QED framework, we obtain the differential cross section of neutrino-electron scattering. Similar to the magnetic moment effect, one of the NC terms is proportional to 1T\frac 1 T, where TT is the electron recoil energy. Therefore, this scattering provides a chance to achieve a stringent bound on the NC scale in low energy by improving the sensitivity to the smaller electron recoil energy.Comment: 12 pages, 2 figure

    TESLA Technical Design Report Part III: Physics at an e+e- Linear Collider

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    The TESLA Technical Design Report Part III: Physics at an e+e- Linear ColliderComment: 192 pages, 131 figures. Some figures have reduced quality. Full quality figures can be obtained from http://tesla.desy.de/tdr. Editors - R.-D. Heuer, D.J. Miller, F. Richard, P.M. Zerwa

    Quantitative measurements of inequality in geographic accessibility to pediatric care in Oita Prefecture, Japan: Standardization with complete spatial randomness

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    <p>Abstract</p> <p>Background</p> <p>A quantitative measurement of inequality in geographic accessibility to pediatric care as well as that of mean distance or travel time is very important for priority setting to ensure fair access to pediatric facilities. However, conventional techniques for measuring inequality is inappropriate in geographic settings. Since inequality measures of access distance or travel time is strongly influenced by the background geographic distribution patterns, they cannot be directly used for regional comparisons of geographic accessibility. The objective of this study is to resolve this issue by using a standardization approach.</p> <p>Methods</p> <p>Travel times to the nearest pediatric care were calculated for all children in Oita Prefecture, Japan. Relative mean differences were considered as the inequality measure for secondary medical service areas, and were standardized with an expected value estimated from a Monte Carlo simulation based on complete spatial randomness.</p> <p>Results</p> <p>The observed mean travel times in the area considered averaged 4.50 minutes, ranging from 1.83 to 7.02 minutes. The mean of the observed inequality measure was 1.1, ranging from 0.9 to 1.3. The expected values of the inequality measure varied according to the background geographic distribution pattern of children, which ranged from 0.3 to 0.7. After standardizing the observed inequality measure with the expected one, we found that the ranks of the inequality measure were reversed for the observed areas.</p> <p>Conclusions</p> <p>Using the indicator proposed in this paper, it is possible to compare the inequality in geographic accessibility among regions. Such a comparison may facilitate priority setting in health policy and planning.</p

    Electroweak phase transitions in the secluded U(1)-prime-extended MSSM

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    The electroweak phase transition (EWPT) in the secluded-U(1)U(1)'-extended MSSM (sMSSM) is studied. Using the effective potential at zero and finite temperatures, we search for the non-MSSM-like EWPT in which the light stop mass is larger than the top quark mass. Scanning the parameters relevant to the EWPT, the upper limits of the Higgs boson masses, which are consistent with the strong first order EWPT, are derived. For the lightest CP-even and -odd Higgs bosons, we find mH1<160m_{H_1}<160 GeV and mA1<250m_{A_1}<250 GeV, respectively. In the sMSSM, the tree-level CP violation is possible by the complex soft supersymmetry breaking masses. It is observed that such a CP-violating effect does not spoil the strong first order EWPT for the typical parameter sets.Comment: 29 pages,15 figures, JHEP style; accepted for publication in JHE
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