The time-dependent angular analysis of $B_d\to K_S\ell \ell$, a new benchmark for new physics

Abstract

We consider the time-dependent analysis of $B_d\to K_S\ell \ell$ taking into account the time-evolution of the $B_d$ meson and its mixing into ${\bar{B}}_d$. We discuss the angular conventions required to define the angular observables in a transparent way with respect to CP conjugation. The inclusion of time evolution allows us to identify six new observables, out of which three could be accessed from a time-dependent tagged analysis. We also show that these observables could be obtained by time-integrated measurements in a hadronic environment if flavour tagging is available. We provide simple and precise predictions for these observables in the SM and in NP models with real contributions to SM and chirally flipped operators, which are independent of form factors and charm-loop contributions. As such, these observables provide robust and powerful cross-checks of the New Physics scenarios currently favoured by global fits to $b\to s\ell \ell$ data. In addition, we discuss the sensitivity of these observables with respect to NP scenarios involving scalar and tensor operators, or CP-violating phases. We illustrate how these new observables can provide a benchmark to discriminate among the various NP scenarios in $b\to s\mu \mu$. We discuss the extension of these results for $B_s$ decays into $f_0$, $\eta$ or ${\eta }^{\prime }$.

Version published in JHEP. Extension of the results for $B_s$ decays into $f_0$, $\eta$ or ${\eta }^{\prime }$ included. 25 pages, 1 figure

References in corpus (12)

• Angular Distributions of B -> K ll Decays
• Rare baryon decays Lambda_b -> Lambda l+ l- (l=e, mu, tau) and Lambda_b -> Lambda gamma : Differential and total rates, lepton- and hadron-side forward-backward asymmetries
• $B_s\to f_0(980)$ form factors and $B_s$ decays into $f_0(980)$
• Model-independent bounds on new physics effects in non-leptonic tree-level decays of B-mesons
• Angular distribution of polarised ${\Lambda }_b$ baryons decaying to $\Lambda {\ell }^{+}{\ell }^{-}$
• New physics in $b\to s{e}^{+}{e}^{-}$?
• Charming New $B$-Physics
• Enhanced CP asymmetries in $B\to K{\mu }^{+}{\mu }^{-}$
• The ${\Lambda }_b\to {\Lambda }^{\ast }(1520)(\to N\bar{K}){\ell }^{+}{\ell }^{-}$ decay at low-recoil in HQET
• $B\to K_2^{\ast }(1430){\ell }^{+}{\ell }^{-}$ distributions in Standard Model at large recoil
• A detailed study of the ${\Lambda }_b\to \Lambda {\ell }^{+}{\ell }^{-}$ decays in the Standard Model
• Angular analyses of exclusive $\overline{B}\to X_J{\ell }_1{\ell }_2$ decays for spin $J\le 4$

Cited by in corpus (11)

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• Heavy Flavour Physics and CP Violation at LHCb: a Ten-Year Review
• A new puzzle in non-leptonic B decays
• Fingerprinting CP-violating New Physics with $B\to K{\mu }^{+}{\mu }^{-}$
• Flavor Physics at the CEPC: a General Perspective
• On the impact of meson mixing on $B_s\to \varphi ee$ angular observables at low $q^2$
• New Perspectives for Testing Electron-Muon Universality
• Fermionic Singlet Dark Matter in One-Loop Solutions to the $R_K$ Anomaly: A Systematic Study
• Targeting (Pseudo)-Scalar CP Violation with $B_s\to {\mu }^{+}{\mu }^{-}$
• First measurement of time-dependent $CP$ violation in the flavor-changing neutral-current decay $B^0\to K_S^0{\mu }^{+}{\mu }^{-}$