Hint of Lepton Flavour Non-Universality in $B$ Meson Decays

Abstract

The LHCb collaboration has recently presented their result on R_K = BR(B+ -> K+ mu+ mu-)/ BR(B+ -> K+ e+ e-) for the dilepton invariant mass bin m_{ll}^2 = 1-6 GeV^2 (l = mu, e). The measurement shows an intriguing 2.6 sigma deviation from the Standard Model (SM) prediction. In view of this, we study model independent New Physics (NP) explanations of R_K consistent with other measurements involving b -> s l l transition, relaxing the assumption of lepton universality. We perform a Bayesian statistical fit to the NP Wilson Coefficients and compare the Bayes Factors of the different hypotheses in order to quantify their goodness-of-fit. We show that the data slightly favours NP in the muon sector over NP in the electron sector.

arXiv commentFinal version, to appear in JHEP

References in corpus (39)

• Big Bang Nucleosynthesis (in "The Review of Particle Properties" 2004)
• CP Violation and the CKM Matrix: Assessing the Impact of the Asymmetric B Factories
• Test of lepton universality using $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ decays
• Measurement of form-factor independent observables in the decay $B^0\to K^{\ast 0}{\mu }^{+}{\mu }^{-}$
• B_{s,d} -> l+ l- in the Standard Model with Reduced Theoretical Uncertainty
• More Model-Independent Analysis of b->s Processes
• Charm-loop effect in $B\to K^{(\ast )}{\ell }^{+}{\ell }^{-}$ and $B\to K^{\ast }\gamma$
• Understanding the B->K*mu+mu- Anomaly
• Dressing L_mu - L_tau in Color
• Angular Distributions of B -> K ll Decays
• Optimizing the basis of B->K*ll observables in the full kinematic range
• 2000 CKM-Triangle Analysis A Critical Review with Updated Experimental Inputs and Theoretical Parameters
• Lattice QCD calculation of form factors describing the rare decays $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$ and $B_s\to \varphi {\ell }^{+}{\ell }^{-}$
• $SU(2)\times U(1)$ gauge invariance and the shape of new physics in rare $B$ decays
• On B -> V l l at small dilepton invariant mass, power corrections, and new physics
• Electromagnetic Logarithms in B -> X_s l+ l-
• On the impact of power corrections in the prediction of B->K*mu+mu- observables
• Comprehensive Bayesian Analysis of Rare (Semi)leptonic and Radiative B Decays
• 331 models facing new b -> s mu^+ mu^- data
• Differential branching fraction and angular analysis of the decay $B^0\to K^{\ast 0}{\mu }^{+}{\mu }^{-}$
• An explicit Z'-boson explanation of the B->K*mu+mu- anomaly
• Left-handed Z' and Z FCNC quark couplings facing new b -> s mu^+ mu^- data
• Calculation of $B^0\to K^{\ast 0}{\mu }^{+}{\mu }^{-}$ and $B_s^0\to \varphi {\mu }^{+}{\mu }^{-}$ observables using form factors from lattice QCD
• On minimal Z' explanations of the B->K*mu+mu- anomaly
• General Analysis of B -> K^(*) l^+ l^- Decays at Low Recoil
• Rare decay B -> K ll form factors from lattice QCD
• Standard Model predictions for B -> Kll with form factors from lattice QCD
• Differential branching fraction and angular analysis of the $B^{+}\to K^{+}{\mu }^{+}{\mu }^{-}$ decay
• Measurement of the B->Xsl+l- branching fraction and search for direct CP violation from a sum of exclusive final states
• Differential branching fraction and angular analysis of the decay ${\mathbf{B}}^0\to {\mathbf{K}}^{\ast 0}{\mathbf{\mu }}^{+}{\mathbf{\mu }}^{-}$
• New Physics in b -> s mu+ mu-: CP-Conserving Observables
• Resonances gone topsy turvy - the charm of QCD or new physics in $b\to s{\ell }^{+}{\ell }^{-}$?
• Explaining the $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$ data with scalar interactions
• Observation of a resonance in $B^{+}\to K^{+}{\mu }^{+}{\mu }^{-}$ decays at low recoil
• Exploring New Physics in the C7-C7' plane
• Enhanced $B_s$--${\bar{B}}_s$ lifetime difference and anomalous like-sign dimuon charge asymmetry from new physics in $B_s\to {\tau }^{+}{\tau }^{-}$
• New Physics in b -> s mu+ mu-: CP-Violating Observables
• Form factors from lattice QCD
• How large can the branching ratio of $B_s\to {\tau }^{+}{\tau }^{-}$ be ?

Cited by in corpus (117)

• On the Standard Model predictions for $R_K$ and $R_{K^{\ast }}$
• Explaining $h\to {\mu }^{\pm }{\tau }^{\mp }$, $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$ and $B\to K{\mu }^{+}{\mu }^{-}/B\to K{e}^{+}{e}^{-}$ in a two-Higgs-doublet model with gauged $L_{\mu }-L_{\tau }$
• Test of lepton universality in beauty-quark decays
• Global analysis of $b\to s\ell \ell$ anomalies
• Patterns of New Physics in $b\to s{\ell }^{+}{\ell }^{-}$ transitions in the light of recent data
• Addressing the LHC flavour anomalies with horizontal gauge symmetries
• Flavour anomalies after the $R_{K^{\ast }}$ measurement
• New physics in $b\to s$ transitions after LHC run 1
• Simultaneous Explanation of the $R_K$ and $R(D^{(\ast )})$ Puzzles
• Lepton Flavor Violation in B Decays?
• Interpreting Hints for Lepton Flavor Universality Violation
• Towards the discovery of new physics with lepton-universality ratios of $b\to s\ell \ell$ decays
• Lepton-flavour violating $B$ decays in generic $Z^{\prime }$ models
• Family non-universal Z' models with protected flavor-changing interactions
• Lepton Flavor Non-Universality in B-meson Decays from a U(2) Flavor Model
• Reassessing the discovery potential of the $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$ decays in the large-recoil region: SM challenges and BSM opportunities
• On the anomalies in the latest LHCb data
• Simultaneous Explanation of the $R_K$ and $R_{D^{(\ast )}}$ Puzzles: a Model Analysis
• A Dark Matter Relic From Muon Anomalies
• Reconsidering the One Leptoquark solution: flavor anomalies and neutrino mass
• Phenomenology of an $SU(2)\times SU(2)\times U(1)$ model with lepton-flavour non-universality
• Rare $B$ Decays as Tests of the Standard Model
• Lepton Flavor Violation in Exclusive $b\to s$ Decays
• New Physics in $b\to s{\ell }^{+}{\ell }^{-}$ confronts new data on Lepton Universality
• Predictions for Lepton Flavor Universality Violation in Rare B Decays in Models with Gauged $L_{\mu }-L_{\tau }$
• Lepton Flavor Non-Universality in B decays from Dynamical Yukawas
• Revisiting the vector leptoquark explanation of the B-physics anomalies
• Diagnosing lepton-nonuniversality in $b\to s\ell \ell$
• Scalar leptoquarks and the rare B meson decays
• Test of lepton universality in $b\to s{\ell }^{+}{\ell }^{-}$ decays
• Gauge-invariant implications of the LHCb measurements on Lepton-Flavour Non-Universality
• Lepton flavor non-universality in $b\to s{\ell }^{+}{\ell }^{-}$ processes
• A leptoquark model to accommodate $R_K^{\exp }<R_K^{\mathrm{SM}}$ and $R_{K^{\ast }}^{\exp }<R_{K^{\ast }}^{\mathrm{SM}}$
• Measurement of lepton universality parameters in $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ and $B^0\to K^{\ast 0}{\ell }^{+}{\ell }^{-}$ decays
• On the Importance of Electroweak Corrections for B Anomalies
• Lepton flavor universality violation without new sources of quark flavor violation
• Explaining the $R_K$ and $R_{K^{\ast }}$ anomalies
• The role of the $S_3$ GUT leptoquark in flavor universality and collider searches
• Minimal flavor-changing $Z^{\prime }$ models and muon $g-2$ after the $R_{K^{\ast }}$ measurement
• A $Z^{\prime }$ Model for $b\to s\ell \bar{\ell }$ Flavour Anomalies
• Z'-induced FCNC decays of top, beauty and strange quarks
• A closer look at the $R_D$ and $R_{D^{\ast }}$ anomalies
• Linear flavour violation and anomalies in B physics
• Lepton Flavor and Non-Universality from Minimal Composite Higgs Setups
• A frequentist analysis of three right-handed neutrinos with GAMBIT
• Implications for New Physics in $b\to s\mu \mu$ transitions after recent measurements by Belle and LHCb
• Direct and indirect signals of natural composite Higgs models
• Implications of $b\to s$ measurements
• Explaining the Lepton Non-universality at the LHCb and CMS from a Unified Framework
• Flavourful $Z^{\prime }$ portal for vector-like neutrino Dark Matter and $R_{K^{(\ast )}}$
• Neutrino mixing and $R_K$ anomaly in $U(1{)}_X$ models: a bottom-up approach
• Large hadronic power corrections or new physics in the rare decay B-->K* mu+ mu- ?
• Flavourful $Z^{\prime }$ models for $R_{K^{(\ast )}}$
• Study of the rare semileptonic decays $B_d^0\to K^{\ast }{l}^{+}{l}^{-}$ in scalar leptoquark model
• LHCb anomalies from a natural perspective
• Is it possible to explain the muon and electron $g-2$ in a $Z^{\prime }$ model?
• Weak decays of unstable $b$-mesons
• SU(5) Unification with TeV-scale Leptoquarks
• Time dependence in $B\to V\ell \ell$ decays
• $R_{D^{(\ast )}}$, $R_{K^{(\ast )}}$ and neutrino mass in the 2HDM-III with right-handed neutrinos
• $R_{K^{(\ast )}}$ and the origin of Yukawa couplings
• Are the B decay anomalies related to neutrino oscillations?
• Dirac dark matter and $b\to s{\ell }^{+}{\ell }^{-}$ with $\mathrm{U}(1)$ gauge symmetry
• Seeking leptoquarks in IceCube
• Charged-Lepton Mixing and Lepton Flavor Violation
• The Case for Future Hadron Colliders From $B\to K^{(\ast )}{\mu }^{+}{\mu }^{-}$ Decays
• $R_K$ and $R_{K^{\ast }}$ in an Aligned 2HDM with Right-Handed Neutrinos
• Stringy explanation of $b\to s{\ell }^{+}{\ell }^{-}$ anomalies
• Reconciling dark matter, $R_{K^{(\ast )}}$ anomalies and $(g-2{)}_{\mu }$ in an $L_{\mu }-L_{\tau }$ scenario
• Reconciling $B$-decay anomalies with neutrino masses, dark matter and constraints from flavour violation
• Angular analysis of the decay B${}^{+}$ $\to$ K${}^{+}{\mu }^{+}{\mu }^{-}$ in proton-proton collisions at $\sqrt{s}=$ 8 TeV
• A nonunitary interpretation for a single vector leptoquark combined explanation to the $B$-decay anomalies
• Revisiting Minimal Lepton Flavour Violation in the Light of Leptonic CP Violation
• More Lepton Flavor Violating Observables for LHCb's Run 2
• Connecting $b\to s\ell \bar{\ell }$ anomalies to enhanced rare nonleptonic ${\bar{B}}_s^0$ decays in $Z^{\prime }$ model
• Minimal Lepton Flavor Violation Implications of the $b\to s$ Anomalies
• Rare b hadron decays at the LHC
• A gauged horizontal $SU(2)$ symmetry and $R_{K^{(\ast )}}$
• $R_{K^{(\ast )}}$ with leptoquarks and the origin of Yukawa couplings
• Exploiting the Symmetries of P and S wave for B --> K^* mu^+ mu^-
• Leptoquark effects on $b\to s\nu \bar{\nu }$ and $B\to K{l}^{+}{l}^{-}$ decay processes
• Systematic approach to $B$-physics anomalies and $t$-channel dark matter
• The strange side of LHCb
• Phenomenology of the simple 3-3-1 model with inert scalars
• Search for $t{Z}^{\prime }$ associated production induced by $tc{Z}^{\prime }$ couplings at the LHC
• Assessing lepton-flavour non-universality from $B\to K^{\ast }\ell \ell$ angular analyses
• Bs to mu mu gamma from Bs to mu mu
• Non-universal Z' from SO(10) GUTs with vector-like family and the origin of neutrino masses
• Flavor anomalies at the LHC and the R-parity violating supersymmetric model extended with vectorlike particles
• Flavour issues in warped custodial models: $B$ anomalies and rare $K$ decays
• Implications of the $R_K$ and $R_{K^{\ast }}$ anomalies
• Origin of Yukawa couplings for Higgs and leptoquarks
• Flavour anomalies on the eve of the Run-2 verdict
• Muon anomalies and the $SU(5)$ Yukawa relations
• Consequences of $b\to s{\mu }^{+}{\mu }^{-}$ anomalies on $B\to K^{(\ast )}\nu \bar{\nu }$, $B_s\to (\eta ,{\eta }^{\prime })\nu \bar{\nu }$ and $B_s\to \varphi \nu \bar{\nu }$ decay observables
• Theoretical status of $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$: The path towards New Physics
• Latest results on rare decays from LHCb
• Light stop in the MSSM after LHC Run 1
• Top FCNC interactions through dimension six four-fermion operators at the electron proton collider
• Long-distance weak annihilation contribution to the $B^{\pm }\to ({\pi }^{\pm },K^{\pm }){\ell }^{+}{\ell }^{-}$ decays
• The fate of $V_1$ vector leptoquarks: the impact of future flavour data
• Impact of Warped Extra Dimensions on the Dipole Coefficients in $\mathbf{b}\to \mathbf{s\gamma }$ Transitions
• On the model dependence of measured Bs-meson branching fractions
• $R_{K^{(\ast )}}$ from RPV-SUSY sneutrinos
• The Waves and the Sigmas (To Say Nothing of the 750 GeV Mirage)
• Investigating New Physics through the Observables of Semileptonic $B_s\to K^{\ast }(\to K\pi ){\mu }^{+}{\mu }^{-}$ Decay
• Rare decays of b hadrons
• Quark and Lepton Mass and Mixing with non-universal $Z^{\prime }$ from a 5d Standard Model with gauged $SO(3)$
• Challenges for New Physics in the Flavour Sector
• Explaining the LHC flavour anomalies
• Testing spin-2 mediator by angular observables in $b\to s{\mu }^{+}{\mu }^{-}$
• Signs for new physics in the recent LHCb data?
• CKM studies from b physics at hadron machines
• Is there really a $W\to \tau \nu$ puzzle?
• Addressing $R_K$ and neutrino mixing in a class of $U(1{)}_X$ models
• New Physics in $B$ decays
• A flavor-safe composite explanation of $R_K$