36 research outputs found

    Factorization and Nonfactorization in B Decays

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    Using NLL values for Wilson coefficients and including the contributions from the penguin diagrams, we estimate the amount of nonfactorization in two-body hadronic B decays. Also, we investigate the model dependence of the nonfactorization parameters by performing the calculation using different models for the form factors. The results support the universality of nonfactorizable contributions in both Cabibbo-favored and Cabibbo-suppressed B decays.Comment: 17 pages, 5 figures, revte

    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.

    Flavour-Conserving CP Phases in Supersymmetry and Implications for Exclusive B Decays

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    We study rare exclusive B decays based on the quark-level transition b->s(d)l^+l^-, where l=e or mu, in the context of supersymmetric theories with minimal flavour violation. We present analytic expressions for various mixing matrices in the presence of new CP-violating phases, and examine their impact on observables involving B and \bar{B} decays. An estimate is obtained for CP-violating asymmetries in B->K^(*)l^+l^- and B->rho(pi)l^+l^- decays for the dilepton invariant mass region 1.2 GeV < M_{l^+l^-}< M_{J/psi}. As a typical result, we find a CP-violating partial width asymmetry of about -6% (-5%) in the case of B->pi (B->rho) in effective supersymmetry with phases of O(1), taking into account the measurement of the inclusive b->s gamma branching fraction. On the other hand, CP asymmetries of less than 1% are predicted in the case of B->K^(*). We argue that it is not sufficient to have additional CP phases of O(1) to observe large CP-violating effects in exclusive b->s(d)l^+l^- decays.Comment: 34 pages, REVTeX, 6 figures, final version to appear in Phys. Rev. D, with some minor addition

    Measurement of the Decay Amplitudes of B0 --> J/psi K* and B0s --> J/psi phi Decays

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    A full angular analysis has been performed for the pseudo-scalar to vector-vector decays, B0 --> J/psi K* and B_s --> J/psi phi, to determine the amplitudes for decays with parity-even longitudinal and transverse polarization and parity-odd transverse polarization. The measurements are based on 190 B0 candidates and 40 B_s candidates collected from a data set corresponding to 89 inverse pb of pbarp collisions at root(s) = 1.8 TeV at the Fermilab Tevatron. In both decays the decay amplitude for longitudinal polarization dominates and the parity-odd amplitude is found to be small.Comment: 7 pages, 3 figures, 1 tabl

    Anemia prevalence in women of reproductive age in low- and middle-income countries between 2000 and 2018

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    Anemia is a globally widespread condition in women and is associated with reduced economic productivity and increased mortality worldwide. Here we map annual 2000–2018 geospatial estimates of anemia prevalence in women of reproductive age (15–49 years) across 82 low- and middle-income countries (LMICs), stratify anemia by severity and aggregate results to policy-relevant administrative and national levels. Additionally, we provide subnational disparity analyses to provide a comprehensive overview of anemia prevalence inequalities within these countries and predict progress toward the World Health Organization’s Global Nutrition Target (WHO GNT) to reduce anemia by half by 2030. Our results demonstrate widespread moderate improvements in overall anemia prevalence but identify only three LMICs with a high probability of achieving the WHO GNT by 2030 at a national scale, and no LMIC is expected to achieve the target in all their subnational administrative units. Our maps show where large within-country disparities occur, as well as areas likely to fall short of the WHO GNT, offering precision public health tools so that adequate resource allocation and subsequent interventions can be targeted to the most vulnerable populations

    Anemia prevalence in women of reproductive age in low- and middle-income countries between 2000 and 2018

    Get PDF
    Anemia is a globally widespread condition in women and is associated with reduced economic productivity and increased mortality worldwide. Here we map annual 2000–2018 geospatial estimates of anemia prevalence in women of reproductive age (15–49 years) across 82 low- and middle-income countries (LMICs), stratify anemia by severity and aggregate results to policy-relevant administrative and national levels. Additionally, we provide subnational disparity analyses to provide a comprehensive overview of anemia prevalence inequalities within these countries and predict progress toward the World Health Organization’s Global Nutrition Target (WHO GNT) to reduce anemia by half by 2030. Our results demonstrate widespread moderate improvements in overall anemia prevalence but identify only three LMICs with a high probability of achieving the WHO GNT by 2030 at a national scale, and no LMIC is expected to achieve the target in all their subnational administrative units. Our maps show where large within-country disparities occur, as well as areas likely to fall short of the WHO GNT, offering precision public health tools so that adequate resource allocation and subsequent interventions can be targeted to the most vulnerable populations.Peer reviewe

    Anemia prevalence in women of reproductive age in low- and middle-income countries between 2000 and 2018

    Get PDF
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