Leptoquark Flavor Patterns & B Decay Anomalies

Abstract

Flavor symmetries that explain masses and mixings of the standard model fermions dictate flavor patterns for the couplings of scalar and vector leptoquarks to the standard model fermions. A generic feature is that couplings to $SU(2)$-doublet leptons are suppressed at least by one spurion of the discrete non-abelian symmetry breaking, responsible for neutrino mixing, while couplings to charged lepton singlets can be order one. We obtain testable patterns including those that predominantly couple to a single lepton flavor, or two, or in a skewed way. They induce lepton non-universality, which we contrast to current anomalies in $B$-decays. We find maximal effects in $R_D$ and $R_{D^{\ast }}$ at the level of $\sim$10 percent and few percent, respectively, while leptoquark effects in $R_{K^{(\ast )}}$ can reach order few$\times 10$ percent. Predictions for charm and kaon decays and $\mu -e$ conversion are worked out.

23 pages plus references and appendices, 2 figures, v2: typos fixed, clarifications and references added; conclusions unchanged

References in corpus (12)

• Test of lepton universality using $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ decays
• On the B to D* tau nu Sensitivity to New Physics
• Measurement of the branching ratio of ${\bar{B}}^0\to D^{\ast +}{\tau }^{-}{\bar{\nu }}_{\tau }$ relative to ${\bar{B}}^0\to D^{\ast +}{\ell }^{-}{\bar{\nu }}_{\ell }$ decays with a semileptonic tagging method
• $R_K$ and future $b\to s\ell \ell$ BSM opportunities
• Simultaneous Explanation of the $R_K$ and $R(D^{(\ast )})$ Puzzles
• Lepton Flavor Violation in B Decays?
• A Simplest A4 Model for Tri-Bimaximal Neutrino Mixing
• Diagnosing lepton-nonuniversality in $b\to s\ell \ell$
• Scalar leptoquarks and the rare B meson decays
• Constraints on two-lepton, two quark operators
• Mu2e Technical Design Report
• Ultraviolet Completion of Flavour Models

Cited by in corpus (15)

• B-physics anomalies: a guide to combined explanations
• Gauge leptoquark as the origin of B-physics anomalies
• $B$ decay anomalies and dark matter from vectorlike confinement
• Probing Lepton Flavour Universality with $K\to \pi \nu \bar{\nu }$ decays
• ${\Lambda }_b\to {\Lambda }_c\tau {\bar{\nu }}_{\tau }$ decay in scalar and vector leptoquark scenarios
• Impact of the $b\to sll$ anomalies on dark matter physics
• SU(5) Unification with TeV-scale Leptoquarks
• Rare semileptonic $B\to K(\pi )l_i^{-}{l}_j^{+}$ decay in vector leptoquark model
• $B$ decay anomalies from nonabelian local horizontal symmetry
• A Three-loop Neutrino Mass Model with a Colored Triplet Scalar
• Direct determination of Wilson coefficients using $B^0\to K^{\ast 0}{\mu }^{+}{\mu }^{-}$ decays
• Charged-lepton-flavor violation in $|\Delta S|=1$ hyperon decays
• Remarks on the Standard Model predictions for $R(D)$ and $R(D^{\ast })$
• Origin of Yukawa couplings for Higgs and leptoquarks
• $b\to c\tau \bar{\nu }$ decays in supersymmetry with $R$-parity violation