New Strategy to Explore CP Violation with $B_s^0\to K^{-}{K}^{+}$

Abstract

The $U$-spin symmetry provides a powerful tool to extract the angle $\gamma$ of the Unitarity Triangle and the $B_s^0$-${\bar{B}}_s^0$ mixing phase ${\varphi }_s$ from CP violation in the $B_s^0\to K^{-}{K}^{+}$, $B_d^0\to {\pi }^{-}{\pi }^{+}$ system. LHCb has obtained first results with uncertainties at the $7^{\circ }$ level. Due to $U$-spin-breaking corrections, it will be challenging to reduce the uncertainty below $\mathcal{O}(5^{\circ })$ at Belle II and the LHCb upgrade. We propose a new strategy, using $\gamma$ as input and utilizing $B_s^0\to K^{-}{\ell }^{+}{\nu }_{\ell }$, $B_d^0\to {\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ decays, which allows an extraction of ${\varphi }_s$ with a future theoretical precision of up to $\mathcal{O}(0.5^{\circ })$, thereby matching the experimental prospects. Since $B_s^0\to K^{-}{K}^{+}$ is dominated by penguin topologies, new sources of CP violation may be revealed.

8 pages, 3 figures

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• Current status of the Standard Model CKM fit and constraints on $\Delta F=2$ New Physics
• $B_{s,d}\to \pi \pi ,\pi K,KK$: Status and Prospects
• A Roadmap to Control Penguin Effects in $B_d^0\to J/\psi K_{\mathrm{S}}^0$ and $B_s^0\to J/\psi \varphi$
• Testing the Standard Model and searching for New Physics with $B_d\to \pi \pi$ and $B_s\to KK$ decays

Cited by in corpus (4)

• In Pursuit of New Physics with $B_d^0\to J/\psi K^0$ and $B_s^0\to J/\psi \varphi$ Decays at the High-Precision Frontier
• Observation of $CP$ violation in two-body $B_{(\mathrm{s})}^0$-meson decays to charged pions and kaons
• Using $B_s^0\to D_s^{\mp }{K}^{\pm }$ Decays as a Portal to New Physics
• Estimating QCD-factorization amplitudes through $SU(3)$ symmetry in $B\to PP$ decays