Diagnosing lepton-nonuniversality in $b\to s\ell \ell$

Abstract

Ratios of branching fractions of semileptonic B decays, $(B\to H\mu \mu )$ over $(B\to Hee)$ with $H=K,K^{\ast },X_s,K_0(1430),\varphi ,\dots$ are sensitive probes of lepton universality. In the Standard Model, the underlying flavor changing neutral current process $b\to s\ell \ell$ is lepton flavor universal. However models with new flavor violating physics above the weak scale can give substantial non-universal contributions. The leading contributions from such new physics can be parametrized by effective dimension six operators involving left- or right-handed quarks. We show that in the double ratios $R_{X_s}/R_K$, $R_{K^{\ast }}/R_K$ and $R_{\varphi }/R_K$ the dependence on new physics coupling to left-handed quarks cancels out. Thus a measurement of any of these double ratios is a clean probe of flavor nonuniversal physics coupling to right-handed quarks. We also point out that the observables $R_{X_s}$, $R_{K^{\ast }}$, $R_{K_0(1430)}$ and $R_{\varphi }$ depend on the same combination of Wilson coefficients and therefore satisfy simple consistency relations.

20 pages, 4 plots; axialvector K1 included

References in corpus (11)

• Big-Bang Nucleosynthesis
• Test of lepton universality using $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ decays
• Measurement of the Differential Branching Fraction and Forward-Backword Asymmetry for B->K(*)l+l-
• Angular Distributions of B -> K ll Decays
• $SU(2)\times U(1)$ gauge invariance and the shape of new physics in rare $B$ decays
• Hint of Lepton Flavour Non-Universality in $B$ Meson Decays
• Global fits to b -> s ll data and signs for lepton non-universality
• Resonances gone topsy turvy - the charm of QCD or new physics in $b\to s{\ell }^{+}{\ell }^{-}$?
• Explaining the Lepton Non-universality at the LHCb and CMS from a Unified Framework
• The effect of S-wave interference on the $B^0\to K^{\ast 0}{\ell }^{+}{\ell }^{-}$ angular observables
• Form factors from lattice QCD

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