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Measuring the weak isospin of b quarks in e + e − annihilation

1992; American Physical Society; Volume: 45; Issue: 9 Linguagem: Inglês

10.1103/physrevd.45.3262

1538-4500

D. Schaile, P.M. Zerwas,

Black Holes and Theoretical Physics

From measurements of the $Z$ decay width to $b$ quarks $\ensuremath{\Gamma}(Z\ensuremath{\rightarrow}b\overline{b})$ and the forward-backward asymmetry ${A}_{\mathrm{FB}}(b)$ of $b$ quarks at ${e}^{+}{e}^{\ensuremath{-}}$ colliders, the weak-isospin components of the left- and right-handed $b$ quarks can unambiguously be determined: ${I}_{3}^{L}(b)=\ensuremath{-}\frac{1}{2}$ and ${I}_{3}^{R}(b)=0$. From the nonzero value of ${I}_{3}^{L}(b)$ the top quark can be inferred as the isospin partner of the $b$ quark.