Recent Heavy-Flavor Measurements from OPAL

A selection of recent heavy-flavor results from OPAL using the LEP1 data sample are presented. The average polarization of b baryons in hadronic Z^0 decay has been measured to be -0.56^{+0.20}_{-0.13} (stat.) +- 0.09(syst.) using semileptonic decays of Lambda_b baryons. A search has been conducted for the radially excited D*' and has produced a 95% CL upper limit on its production of f(Z^0 -> D*'+-(2629))xBr(D*'+- -> D*+- pi+ pi-) < 2.1x10^{-3}. Finally, the measurement of the product branching ratio $f(b -> Lambda_b)xBr(Lambda_b -> Lambda X)= (2.67 +- 0.38 (stat) ^{+0.67}_{-0.60}(syst.))% has been made. This measurement, along with an earlier measurement of the product branching ratio f(b -> Lambda_b)xBr(Lambda_b -> Lambda l X), has been used to compute an updated R_{Lambda l} = Br(Lambda_b -> Lambda l X)/Br(Lambda_b -> \Lambda X)= (8.0 +- 1.2 (stat.) +- 0.9 (syst.))%, consistent with the expected low semileptonic branching fraction of the Lambda_b inferred from its short lifetime compared to the other b hadrons.Comment: 9 Pages, LaTeX, 4 figures. Proceedings contributed to DPF'99, UCLA, Parallel session talk 3.0

Prospects for a low-mass Higgs boson

The SU(2){sub L} x U(1){sub Y} gauge theory of the electroweak interactions has enjoyed tremendous success over the past four decades, accurately predicting, or at least accommodating, all high-energy collider data. The gauge group must be broken somehow to U(1){sub EM}, because the unbroken theory predicts massless gauge bosons and massless fermions. The Standard Model incorporates a minimal Higgs sector with a single complex doublet field, to break the symmetry spontaneously, but it is not the only possibility. SUSY Higgses, general two-Higgs-doublet models, and other ideas may prove to model nature better than the minimal model. Many of these models, and even the SM, prefer a light Higgs boson, with a mass between the LEP limit of 114.4 GeV and 200 GeV. The Constrained MSSM favors masses under 120 GeV. A survey of the experimental work so far at LEP and the Tevatron, with estimations of the sensitivity of the upcoming LHC experiments is provided

Tribromo(3,5-dimethyl-2-nitrophenyl-j2 C1 ,O)tellurium(IV), bromo(3,5-dimethyl-2-nitrophenyl-j2 C1 ,O)tellurium(II) and bromo(3,5-dimethyl-2-nitrosophenyl-j2 C1 ,O)tellurium(II)

All three title compounds, prepared from bis(3,5-dimethyl-2- nitrophenyl)ditellurium, exhibit high degrees of intramolecular TeÐO coordination. Their TeÐO distances increase in the order C8H8BrNOTe \u3c C8H8BrNO2Te \u3c C8H8Br3NO2Te, with distances of 2.165 (3), 2.306 (1) and 2.423 (6) AÊ , respectively, indicating that C8H8BrNOTe may be more aptly described as 1-bromo-4,6-dimethyl-2,1,3-benzoxatellurazole

(μ-Diazenediyldiphenyl-κ2C2, N2: κ2C2′, N1) bis [(3, 5-dimethylphenyl) tellurium (II)].

The title compound, C28H26N2Te2, prepared by reduction of (3,5-dimethylphenyl)(2-nitrophenyl)tellurium(II), is the first structurally characterized example of an azo group bridging two TeII centers. The compound is centrosymmetric and the Te—N distance [2.6916 (19) A ° ] is longer than in non-bridging azo compounds

Observation of Single Top Quark Production

The field of experimental particle physics has become more sophisticated over time, as fewer, larger experimental collaborations search for small signals in samples with large components of background. The search for and the observation of electroweak single top quark production by the CDF and DZero collaborations at Fermilab's Tevatron collider are an example of an elaborate effort to measure the rate of a very rare process in the presence of large backgrounds and to learn about the properties of the top quark's weak interaction. We present here the techniques used to make this groundbreaking measurement and the interpretation of the results in the context of the Standard Model.Comment: 33 pages, 14 figures, 4 tables, to appear in Annual Review of Nuclear and Particle Science, Vol. 61, November 201

A Review of the Potential Climate Change Impacts and Adaptation Options for European Viticulture

Viticulture and winemaking are important socioeconomic sectors in many European regions. Climate plays a vital role in the terroir of a given wine region, as it strongly controls canopy microclimate, vine growth, vine physiology, yield, and berry composition, which together determine wine attributes and typicity. New challenges are, however, predicted to arise from climate change, as grapevine cultivation is deeply dependent on weather and climate conditions. Changes in viticultural suitability over the last decades, for viticulture in general or the use of specific varieties, have already been reported for many wine regions. Despite spatially heterogeneous impacts, climate change is anticipated to exacerbate these recent trends on suitability for wine production. These shifts may reshape the geographical distribution of wine regions, while wine typicity may also be threatened in most cases. Changing climates will thereby urge for the implementation of timely, suitable, and cost-effective adaptation strategies, which should also be thoroughly planned and tuned to local conditions for an effective risk reduction. Although the potential of the different adaptation options is not yet fully investigated, deserving further research activities, their adoption will be of utmost relevance to maintain the socioeconomic and environmental sustainability of the highly valued viticulture and winemaking sector in Europe.This study was funded by Clim4Vitis project—“Climate change impact mitigation for European viticulture: knowledge transfer for an integrated approach”, funded by the European Union’s Horizon 2020 Research and Innovation Programme, under grant agreement no. 810176; it was also supported by FCT—Portuguese Foundation for Science and Technology, under the project UIDB/04033/2020

A review of the potential climate change impacts and adaptation options for European viticulture

Viticulture and winemaking are important socioeconomic sectors in many European regions. Climate plays a vital role in the terroir of a given wine region, as it strongly controls canopy microclimate, vine growth, vine physiology, yield, and berry composition, which together determine wine attributes and typicity. New challenges are, however, predicted to arise from climate change, as grapevine cultivation is deeply dependent on weather and climate conditions. Changes in viticultural suitability over the last decades, for viticulture in general or the use of specific varieties, have already been reported for many wine regions. Despite spatially heterogeneous impacts, climate change is anticipated to exacerbate these recent trends on suitability for wine production. These shifts may reshape the geographical distribution of wine regions, while wine typicity may also be threatened in most cases. Changing climates will thereby urge for the implementation of timely, suitable, and cost-effective adaptation strategies, which should also be thoroughly planned and tuned to local conditions for an effective risk reduction. Although the potential of the different adaptation options is not yet fully investigated, deserving further research activities, their adoption will be of utmost relevance to maintain the socioeconomic and environmental sustainability of the highly valued viticulture and winemaking sector in Europe. © 2020 by the authors