825 research outputs found

    Asymmetry Parameter of the K1(1270,1400)K_{1} (1270, 1400) by Analyzing the BK1ννˉB\to K_{1}\nu \bar{\nu} Transition Form Factors within QCD

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    Separating the mixture of the K1(1270) K_{1}(1270) and K1(1400)K_{1}(1400) states, the BK1(1270,1400)ννˉB\to K_{1}(1270, 1400)\nu\bar{\nu} transition form factors are calculated in the three-point QCD sum rules approach. The longitudinal, transverse and total decay widths as well as the asymmetry parameter, characterizing the polarization of the axial K1(1270,1400)K_{1}(1270, 1400) and the branching ratio for these decays are evaluated.Comment: 25 pages, 3 figures, 3 table

    Domestic Value Added and Employment Generated by Chinese Exports: A Quantitative Estimation

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    We develop an input-output methodology to estimate how Chinese exports affect the country’s total domestic value added (DVA) and employment for 1995 and 2002. Total DVA generated by exports is obtained by subtracting all direct and indirect imported intermediate goods from the gross value of exports, and total employment is obtained by adding all direct and indirect employment generated by exports. To implement these estimations, we use hitherto unpublished Chinese government data to construct several completely new datasets, including an input-output table with separate input-output and employment-output coefficients for processing and non-processing exports. In 2002 (1995), for every US1,000dollarofChineseexports,DVAandemploymentareestimatedtobeUS1,000 dollar of Chinese exports, DVA and employment are estimated to be US466 (US$545) and 0.242 (0.375) person-year, respectively.Input-output tables, Chinese exports, employment, domestic value added

    Indigenous sharing, collaboration and synchronous learning

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    Online learning is progressively accepted in Indigenous communities with the realized potential for sharing, collaboration and learning for adults living in remote and isolated communities. This study used a design-based research approach that provided opportunity to integrate the current literature, literacy practitioners\u27 views and community members\u27 self identified literacy needs to generate ten draft guiding principles which guided this study. A collaborative community engagement project was created by the community members in consideration of these principles and presented in three iterations in a synchronous environment which will lead to design-based principles for working with technology and Indigenous communities. This paper examines the framework and approach for this study, provides a short literature review and presents the draft guiding principles drawn from data collected from the stakeholders and from which the project was created

    Updated Analysis of a_1 and a_2 in Hadronic Two-body Decays of B Mesons

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    Using the recent experimental data of BD()(π,ρ)B\to D^{(*)}(\pi,\rho), BD()Ds()B\to D^{(*)} D_s^{(*)}, BJ/ψK()B\to J/\psi K^{(*)} and various model calculations on form factors, we re-analyze the effective coefficients a_1 and a_2 and their ratio. QCD and electroweak penguin corrections to a_1 from BD()Ds()B\to D^{(*)}D_s^{(*)} and a_2 from BJ/ψK()B\to J/\psi K^{(*)} are estimated. In addition to the model-dependent determination, the effective coefficient a_1 is also extracted in a model-independent way as the decay modes BD()hB\to D^{(*)}h are related by factorization to the measured semileptonic distribution of BD()νˉB\to D^{(*)}\ell \bar\nu at q2=mh2q^2=m_h^2. Moreover, this enables us to extract model-independent heavy-to-heavy form factors, for example, F0BD(mπ2)=0.66±0.06±0.05F_0^{BD}(m_\pi^2)=0.66\pm0.06\pm0.05 and A0BD(mπ2)=0.56±0.03±0.04A_0^{BD^*}(m_\pi^2)=0.56\pm0.03\pm0.04. The determination of the magnitude of a_2 from BJ/ψK()B\to J/\psi K^{(*)} depends on the form factors F1BKF_1^{BK}, A1,2BKA_{1,2}^{BK^*} and VBKV^{BK^*} at q2=mJ/ψ2q^2=m^2_{J/\psi}. By requiring that a_2 be process insensitive (i.e., the value of a_2 extracted from J/ψKJ/\psi K and J/ψKJ/\psi K^* states should be similar), as implied by the factorization hypothesis, we find that BK()B\to K^{(*)} form factors are severely constrained; they respect the relation F1BK(mJ/ψ2)1.9A1BK(mJ/ψ2)F_1^{BK}(m^2_{J/\psi})\approx 1.9 A_1^{BK^*}(m^2_{J/\psi}). Form factors A2BKA_2^{BK^*} and VBKV^{BK^*} at q2=mJ/ψ2q^2=m^2_{J/\psi} inferred from the measurements of the longitudinal polarization fraction and the P-wave component in BJ/ψKB\to J/\psi K^* are obtained. A stringent upper limit on a_2 is derived from the current bound on \ov B^0\to D^0\pi^0 and it is sensitive to final-state interactions.Comment: 33 pages, 2 figures. Typos in Tables I and IX are corrected. To appear in Phys. Rev.

    The Quark-Gluon Plasma in a Finite Volume

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    The statistical mechanics of quarks and gluons are investigated within the context of the canonical ensemble. Recursive techniques are developed which enforce the exact conservation of baryon number, total isospin, electric charge, strangeness, and color. Bose and Fermi-Dirac statistics are also accounted for to all orders. The energy, entropy and particle number densities are shown to be significantly reduced for volumes less than 5 cubic fm.Comment: 8 pages, 3 figure

    Isospin Fluctuations from a Thermally Equilibrated Hadron Gas

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    Partition functions, multiplicity distributions, and isospin fluctuations are calculated for canonical ensembles in which additive quantum numbers as well as total isospin are strictly conserved. When properly accounting for Bose-Einstein symmetrization, the multiplicity distributions of neutral pions in a pion gas are significantly broader as compared to the non-degenerate case. Inclusion of resonances compensates for this broadening effect. Recursion relations are derived which allow calculation of exact results with modest computer time.Comment: 10 pages, 5 figure

    Analysis of BRAF and NRAS Mutation Status in Advanced Melanoma Patients Treated with Anti-CTLA-4 Antibodies: Association with Overall Survival?

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    Ipilimumab and tremelimumab are human monoclonal antibodies (Abs) against cytotoxic T-lymphocyte antigen-4 (CTLA-4). Ipilimumab was the first agent to show a statistically significant benefit in overall survival in advanced melanoma patients. Currently, there is no proven association between the BRAFV600 mutation and the disease control rate in response to ipilimumab. This analysis was carried out to assess if BRAFV600 and NRAS mutation status affects the clinical outcome of anti-CTLA-4-treated melanoma patients. This is a retrospective multi-center analysis of 101 patients, with confirmed BRAF and NRAS mutation status, treated with anti-CTLA-4 antibodies from December 2006 until August 2012. The median overall survival, defined from the treatment start date with the anti-CTLA-4. Abs-treatment to death or till last follow up, of BRAFV600 or NRAS mutant patients (n = 62) was 10.12 months (95% CI 6.78-13.2) compared to 8.26 months (95% CI 6.02-19.9) in BRAFV600/NRASwt subpopulation (n = 39) (p = 0.67). The median OS of NRAS mutated patients (n = 24) was 12.1 months and although was prolonged compared to the median OS of BRAF mutated patients (n = 38, mOS = 8.03 months) or BRAFV600/NRASwt patients (n = 39, mOS = 8.26 months) the difference didn't reach statistical significance (p = 0.56). 69 patients were able to complete 4 cycles of anti-CTLA-4 treatment. Of the 24 patients treated with selected BRAF- or MEK-inhibitors, 16 patients received anti-CTLA 4 Abs following either a BRAF or MEK inhibitor with only 8 of them being able to finish 4 cycles of treatment. Based on our results, there is no difference in the median OS in patients treated with anti-CTLA-4 Abs implying that the BRAF/NRAS mutation status alone is not sufficient to predict the outcome of patients treated with anti-CTLA-4 Abs

    The transition form factors for semi-leptonic weak decays of J/ψJ/\psi in QCD sum rules

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    Within the Standard Model, we investigate the semi-leptonic weak decays of J/ψJ/\psi. The various form factors of J/ψJ/\psi transiting to a single charmed meson (D(d,s)()D^{(*)}_{(d,s)}) are studied in the framework of the QCD sum rules. These form factors fully determine the rates of the weak semi-leptonic decays of J/ψJ/\psi and provide valuable information about the non-perturbative QCD effects. Our results indicate that the decay rate of the semi-leptonic weak decay mode J/ψDs()+e++νeJ/\psi \to D^{(*)-}_{s}+e^{+}+\nu_{e} is at order of 101010^{-10}.Comment: 28 pages, 6 figures, revised version to be published in Eur.Phys.J.

    Analysis of the vertices DDVDDV and DDVD^*DV with light-cone QCD sum rules

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    In this article, we study the vertices DDVDDV and DDVD^*DV with the light-cone QCD sum rules. The strong coupling constants gDDVg_{DDV} and fDDVf_{D^*DV} play an important role in understanding the final-state re-scattering effects in the hadronic B decays. They are related to the basic parameters β\beta and λ\lambda respectively in the heavy quark effective Lagrangian, our numerical values are smaller than the existing estimations.Comment: 16 pages, 6 figures, revised versio
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