VENUS CollaborationThe polarization of τ leptons in the reaction e + e − → τ + τ − has been measured using a e + e − collider, TRISTAN, at the center-of-mass energy of 58 GeV. From the kinematical distributions of daughter particles in τ → eνν, µνν, ρν or π(K)ν decays, the average polarization of τ − and its forward-backward asymmetry have been evaluated to be 0.012±0.058 and 0.029±0.057, respectively.

This paper examines the impact of ethnic divisions on conflict. The empirical specification is informed by a theoretical model of conflict (Esteban and Ray, 2011) in which equilibrium conflict intensity is related to just three distributional indices of diversity: ethnic polarization, ethnic fractionalization, and a Greenberg-Gini index of "difference" constructed across ethnic groups. Our empirical findings verify that these distributional measures are significant correlates of conflict. The underlying theory permits us to use these results to make inferences about the relative importance of public goods in conflict, as well as the extent of within-group cohesion in conflictual activity. These effects are further strengthened as we introduce country-specific measures of group cohesion and the relative importance of public goods, and combine them with the distributional measures exactly as specified by the theory.

We develop the measurement theory of polarization for the case in which income distributions can be described using density functions. The main theorem uniquely characterizes a class of polarization measures that fit into what we call the "identity-alienation" framework, and simultaneously satisfies a set of axioms. Second, we provide sample estimators of population polarization indices that can be used to compare polarization across time or entities.Distribution-free statistical inference results are also used in order to ensure that the orderings of polarization across entities are not simply due to samplingnoise. An illustration of the use of these tools using data from 21 countries shows that polarization and inequality orderings can often differ in practice.

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In this paper we study a behavioral model of conflict that provides a basis for choosing certain indices of dispersion as indicators for conflict. We show that a suitable monotone transform of the equilibrium level of conflict can be proxied by a linear function of the Gini coefficient, the Herfindahl-Hirschman fractionalization index, and a specific measure of polarization due to Esteban and Ray. D31