259 research outputs found

    The double charm decays of B Mesons in the mSUGRA model

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    Based on the low energy effective Hamiltonian with naive factorization, we calculate the branching ratios(BRs) and CP asymmetries (CPAs) for the twenty three double charm decays B/BsD(s)()D(s)()B/B_s \to D^{(*)}_{(s)} D^{(*)}_{(s)} in both the standard model (SM) and the minimal supergravity (mSUGRA) model. Within the considered parameter space, we find that (a) the theoretical predictions for the BRs, CPAs and the polarization fractions in the SM and the mSUGRA model are all consistent with the currently available data within ±2σ\pm 2\sigma errors; (b) For all the considered decays, the supersymmetric contributions in the mSUGRA model are very small, less than 7%7\% numerically. It may be difficult to observe so small SUSY contributions even at LHC.Comment: 15 pages, 5tables, no figure

    Bs(d)0Bˉs(d)0B^0_{s(d)} - \bar{B}^0_{s(d)} mixing and new physics effects in a top quark two-Higgs doublet model

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    We calculate the new physics contributions to the neutral Bd0B_d^0 and Bs0B_s^0 meson mass splitting ΔMd\Delta M_d and ΔMs\Delta M_s induced by the box diagrams involving the charged-Higgs bosons in the top quark two-Higgs doublet model (T2HDM). Using the precision data, we obtain the bounds on the parameter space of the T2HDM: (a) for fixed MH=400M_H=400 GeV and δ=[0,60]\delta=[0^\circ,60^\circ], the upper bound on tanβ\tan{\beta} is tanβ30\tan \beta \leq 30 after the inclusion of major theoretical uncertainties; (b) for the case of tanβ20\tan{\beta} \leq 20, a light charged Higgs boson with a mass around 300 GeV is allowed; and (c) the bounds on tanβ\tan{\beta} and MHM_H are strongly correlated: a smaller (larger) tanβ\tan{\beta} means a lighter (heavier) charged Higgs boson.Comment: 11 pages, 2 EPS figures, RevTex, new references adde

    Drought resistance index screening and evaluation of lettuce under water deficit conditions on the basis of morphological and physiological differences

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    IntroductionWater is one of the important factors affecting the yield of leafy vegetables. Lettuce, as a widely planted vegetable, requires frequent irrigation due to its shallow taproot and high leaf evaporation rate. Therefore, screening drought-resistant genotypes is of great significance for lettuce production.MethodsIn the present study, significant variations were observed among 13 morphological and physiological traits of 42 lettuce genotypes under normal irrigation and water-deficient conditions.ResultsFrequency analysis showed that soluble protein (SP) was evenly distributed across six intervals. Principal component analysis (PCA) was conducted to transform the 13 indexes into four independent comprehensive indicators with a cumulative contribution ratio of 94.83%. The stepwise regression analysis showed that root surface area (RSA), root volume (RV), belowground dry weight (BDW), soluble sugar (SS), SP, and leaf relative water content (RWC) could be used to evaluate and predict the drought resistance of lettuce genotypes. Furthermore, the drought resistance ranks of the genotypes were similar according to the drought resistance comprehensive evaluation value (D value), comprehensive drought resistance coefficient (CDC), and weight drought resistance coefficient (WDC). The cluster analysis enabled the division of the 42 genotypes into five drought resistance groups; among them, variety Yidali151 was divided into group I as a strongly drought-resistant variety, group II included 6 drought-resistant genotypes, group III included 16 moderately drought-resistant genotypes, group IV included 12 drought-sensitive genotypes, and group V included 7 highly drought-sensitive genotypes. Moreover, a representative lettuce variety was selected from each of the five groups to verify its water resistance ability under water deficit conditions. In the drought-resistant variety, it was observed that stomatal density, superoxide anion (O2.−wfi2) production rate, and malondialdehyde (MDA) content exhibited a low increase rate, while catalase (CAT), superoxide dismutase (SOD), and that peroxidase (POD) activity exhibited a higher increase than in the drought-sensitive variety.DiscussionIn summary, the identified genotypes are important because their drought-resistant traits can be used in future drought-resistant lettuce breeding programs and water-efficient cultivation

    The rare decays BXs,dννˉB \to X_{s,d} \nu \bar \nu and Bs,dl+lB_{s,d} \to l^+l^- in the Multiscale Walking Technicolor Model

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    We calculate the contributions to the rare B-decays, BXs,dννˉB \to X_{s,d} \nu \bar \nu, Bs,dl+lB_{s,d} \to l^+l^- from the unit-charged technipions. Within the considered parameter space we find that: (a) the enhancements to the branching ratios in question can be as large as three orders of magnitude; (b) the ALEPH data of BXsννˉB \to X_s \nu \bar \nu lead to strong mass bounds on mp1m_{p1} and mp8m_{p8}: mp8620,475GeVm_{p8} \geq 620, 475 GeV for FQ=40GeVF_Q=40GeV and mp1=100,400GeVm_{p1}=100, 400 GeV respectively. (c) the CDF data of BsμμˉB_s \to \mu \bar \mu lead to a relatively weak limit: mp8320GeVm_{p8} \geq 320 GeV for FQ=40GeVF_Q=40GeV and mp1=200GeVm_{p1}=200 GeV.Comment: Latex file, 6 pages with 2 ps figure

    ‘Emptying the cage, changing the birds’: state rescaling, path-dependency and the politics of economic restructuring in post-crisis Guangdong

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    This paper evaluates how economic restructuring in Guangdong is entwined with the politicization of state rescaling during and after the global financial crisis of 2008. It shows how a key industrial policy known as ‘double relocation’ generated tensions between the Guangdong government, then led by Party Secretary Wang Yang, and the senior echelon of the Communist Party of China in Beijing. The contestations and negotiations that ensued illustrate the dynamic entwinement between state rescaling and institutional path-dependency: the Wang administration launched this industrial policy in spite of potentially destabilizing effects on the prevailing national structure of capital accumulation. This foregrounds, in turn, the constitutive and constraining effects of established, national-level policies on local, territorially-specific restructuring policies

    Erratum to: Binding Energy and Spin-Orbit Splitting of a Hydrogenic Donor Impurity in AlGaN/GaN Triangle-Shaped Potential Quantum Well

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    In the framework of effective-mass envelope function theory, including the effect of Rashba spin-orbit coupling, the binding energyEband spin-orbit split energy Г of the ground state of a hydrogenic donor impurity in AlGaN/GaN triangle-shaped potential heterointerface are calculated. We find that with the electric field of the heterojunction increasing, (1) the effective width of quantum well decreases and (2) the binding energy increases monotonously, and in the mean time, (3) the spin-orbit split energy Г decreases drastically. (4) The maximum of Г is 1.22 meV when the electric field of heterointerface is 1 MV/cm
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