Model-independent extraction of |V_{tq}| matrix elements from top-quark measurements at hadron colliders
(2012) European Physical Journal C. Particles and Fields — Vol. 72, p. 2048 (2012)
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- Abstract
- Current methods to extract the quark-mixing matrix element $|V_{tb}|$ from single-top production measurements assume that $|V_{tb}|\gg |V_{td}|, |V_{ts}|$: top quarks decay into $b$ quarks with 100% branching fraction, s-channel single-top production is always accompanied by a $b$ quark and initial-state contributions from $d$ and $s$ quarks in the $t$-channel production of single top quarks are neglected. Triggered by a recent measurement of the ratio $R=\frac{|V_{tb}|^{2}}{|V_{td}|^{2}+|V_{ts}|^{2}+|V_{tb}|^{2}}=0.90 \pm 0.04$ performed by the D0 collaboration, we consider a $|V_{tb}|$ extraction method that takes into account non zero d- and s-quark contributions both in production and decay. We propose a strategy that allows to extract consistently and in a model-independent way the quark mixing matrix elements $|V_{td}|$, $|V_{ts}|$, and $|V_{tb}|$ from the measurement of $R$ and from single-top measured event yields. As an illustration, we apply our method to the Tevatron data using a CDF analysis of the measured single-top event yield with two jets in the final state one of which is identified as a $b$-quark jet. We constrain the $|V_{tq}|$ matrix elements within a four-generation scenario by combining the results with those obtained from direct measurements in flavor physics and determine the preferred range for the top-quark decay width within different scenarios.
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Lacker, H., Menzel, A., Spettel, F., Hirschbuhl, D., Luck, J., Maltoni, F., Wagner, W., & Zaro, M. (2012). Model-independent extraction of |V_{tq}| matrix elements from top-quark measurements at hadron colliders. European Physical Journal C. Particles and Fields, 72, 2048. https://doi.org/10.1140/epjc/s10052-012-2048-4 (Original work published 2012)