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Constraining New Physics with the CDF Measurement of CP Violation in $B \to ψK_S$

Gabriela Barenboim·Galit Eyal·Yosef Nir
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Abstract

Recently, the CDF collaboration has reported a measurement of the CP asymmetry in the $B\toψK_S$ decay: $a_{ψK_S}=0.79^{+0.41}_{-0.44}$. We analyze the constraints that follow from this measurement on the size and the phase of contributions from new physics to $B-\barB$ mixing. Defining the relative phase between the full $M_{12}$ amplitude and the Standard Model contribution to be $2θ_d$, we find a new bound: $\sin2θ_d\gsim-0.6 (-0.87)$ at one sigma (95% CL). Further implications for the CP asymmetry in semileptonic B decays are discussed.

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Gabriela Barenboim, Galit Eyal, Yosef Nir. 1999-10-05. Constraining New Physics with the CDF Measurement of CP Violation in $B \to ψK_S$. https://doi.org/10.1103/physrevlett.83.4486

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