5 research outputs found

    Measurement of the Muon Decay Parameter delta

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    The muon decay parameter delta has been measured by the TWIST collaboration. We find delta = 0.74964 +- 0.00066(stat.) +- 0.00112(syst.), consistent with the Standard Model value of 3/4. This result implies that the product Pmuxi of the muon polarization in pion decay, Pmu, and the muon decay parameter xi falls within the 90% confidence interval 0.9960 < Pmuxi < xi < 1.0040. It also has implications for left-right-symmetric and other extensions of the Standard Model.Comment: Extended to 5 pages. Referee's comments answere

    Measurement of the Michel Parameter ρ\rho in Muon Decay

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    The TWIST Collaboration has measured the Michel parameter ρ\rho in normal muon decay, μ+e+νeνˉμ\mu^+ \to e^+ \nu_e \bar{\nu}_{\mu}. In the Standard Model, ρ\rho = 3/4. Deviations from this value require mixing of left- and right-handed muon and electron couplings in the muon-decay Lagrangian. We find ρ\rho = 0.75080 ±\pm 0.00044(stat.) ±\pm 0.00093(syst.) ±\pm 0.00023, where the last uncertainty represents the dependence of ρ\rho on the Michel parameter η\eta. This result sets new limits on the WLWRW_L-W_R mixing angle in left-right symmetric models.Comment: 4 pages, 3 figures, submitted to PR

    Diversity and diversification: ecosystem services derived from underutilized crops and their co-benefits for sustainable agricultural landscapes and resilient food systems in Africa

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    There are growing calls to adopt more sustainable forms of agriculture that balance the need to increase production with environmental, human health, and wellbeing concerns. Part of this conversation has included a debate on promoting and mainstreaming neglected and underutilized crop species (NUS) because they represent a more ecologically friendly type of agriculture. We conducted a systematic review to determine the ecosystem services derived from NUS and assess their potential to promote functional ecological diversity, food and nutritional security, and transition to more equitable, inclusive, sustainable and resilient agricultural landscapes and food systems in Africa. Our literature search yielded 35 articles for further analysis. The review showed that NUS provide various provisioning, regulating, cultural, and supporting ecosystem services and several environmental and health co-benefits, dietary diversity, income, sustainable livelihood outcomes, and economic empowerment, especially for women. Importantly, NUS address the three pillars of sustainable development- ecological, social, and economic. Thus, NUS may provide a sustainable, fit-for-purpose transformative ecosystem-based adaptation solution for Africa to transition to more sustainable, healthy, equitable, and resilient agricultural landscapes and food systems
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