Interpreting Hints for Lepton Flavor Universality Violation

Abstract

We interpret the recent hints for lepton flavor universality violation in rare $B$ meson decays. Based on a model-independent effective Hamiltonian approach, we determine regions of new physics parameter space that give a good description of the experimental data on $R_K$ and $R_{K^{\ast }}$, which is in tension with Standard Model predictions. We suggest further measurements that can help narrowing down viable new physics explanations. We stress that the measured values of $R_K$ and $R_{K^{\ast }}$ are fully compatible with new physics explanations of other anomalies in rare $B$ meson decays based on the $b\to s\mu \mu$ transition. If the hints for lepton flavor universality violation are first signs of new physics, perturbative unitarity implies new phenomena below a scale of $\sim 100$ TeV.

5 pages, 3 figures. v2: (belated) update to published version

References in corpus (30)

• Test of lepton universality using $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ decays
• 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 $L_{\mu }-L_{\tau }$
• Measurement of the Differential Branching Fraction and Forward-Backword Asymmetry for B->K(*)l+l-
• Addressing the LHC flavour anomalies with horizontal gauge symmetries
• Angular Distributions of B -> K ll Decays
• $R_K$ 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?
• Measurement of the $B_s^0\to {\mu }^{+}{\mu }^{-}$ branching fraction and effective lifetime and search for $B^0\to {\mu }^{+}{\mu }^{-}$ decays
• $SU(2)\times U(1)$ gauge invariance and the shape of new physics in rare $B$ decays
• Leptoquark model to explain the $B$-physics anomalies, $R_K$ and $R_D$
• On the impact of power corrections in the prediction of B->K*mu+mu- observables
• B-decay Anomalies in a Composite Leptoquark Model
• Hint of Lepton Flavour Non-Universality in $B$ Meson Decays
• Family non-universal Z' models with protected flavor-changing interactions
• Status of the $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$ anomaly after Moriond 2017
• Lepton Flavor Non-Universality in B decays from Dynamical Yukawas
• Diagnosing lepton-nonuniversality in $b\to s\ell \ell$
• Global fits to b -> s ll data and signs for lepton non-universality
• Hadronic uncertainties in $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$: a state-of-the-art analysis
• LHCb anomaly and $B$ physics in flavored Z${}^{\prime }$ models with flavored Higgs doublets
• 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- ?
• $B_s\to {\mu }^{+}{\mu }^{-}$ as current and future probe of new physics
• LHCb anomalies from a natural perspective
• Measuring the Breaking of Lepton Flavour Universality in $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$
• SU(5) Unification with TeV-scale Leptoquarks
• Search for the Decays $B_{(s)}^0\to e^{+}{\mu }^{-}$ and $B_{(s)}^0\to e^{+}{e}^{-}$ in CDF Run II
• Flavour Anomalies in $b\to s{\ell }^{+}{\ell }^{-}$ Processes - a round table Discussion
• Status of New Physics searches with $b\to s{\ell }^{+}{\ell }^{-}$ transitions @ LHCb

Cited by in corpus (178)

• B-physics anomalies: a guide to combined explanations
• Search for lepton-universality violation in $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ decays
• Flavour anomalies after the $R_{K^{\ast }}$ measurement
• Effective description of general extensions of the Standard Model: the complete tree-level dictionary
• $B$ Meson Anomalies in a Pati-Salam Model within the Randall-Sundrum Background
• Gauge leptoquark as the origin of B-physics anomalies
• Closing the window on single leptoquark solutions to the $B$-physics anomalies
• B-decay discrepancies after Moriond 2019
• A model of vector leptoquarks in view of the $B$-physics anomalies
• Baryon Number and Lepton Universality Violation in Leptoquark and Diquark Models
• Wilson: a Python package for the running and matching of Wilson coefficients above and below the electroweak scale
• Importance of Loop Effects in Explaining the Accumulated Evidence for New Physics in B Decays with a Vector Leptoquark
• Review of Lepton Universality tests in B decays
• $B\to P$ and $B\to V$ Form Factors from $B$-Meson Light-Cone Sum Rules beyond Leading Twist
• New Physics in $b\to s{\mu }^{+}{\mu }^{-}$ after the Measurement of $R_{K^{\ast }}$
• On the single leptoquark solutions to the $B$-physics anomalies
• Maximal Flavour Violation: a Cabibbo mechanism for leptoquarks
• A Global Likelihood for Precision Constraints and Flavour Anomalies
• New Physics in $b\to s{\ell }^{+}{\ell }^{-}$ confronts new data on Lepton Universality
• Searching for New Physics with $b\to s{\tau }^{+}{\tau }^{-}$ processes
• Left-Right SU(4) Vector Leptoquark Model for Flavor Anomalies
• The $B$ Anomalies and New Physics in $b\to s{e}^{+}{e}^{-}$
• Update on the b->s anomalies
• Pati-Salam explanations of the B-meson anomalies
• Global Fit to Modified Neutrino Couplings and the Cabibbo-Angle Anomaly
• Combined Explanations of the $b\to s{\mu }^{+}{\mu }^{-}$ and $b\to c{\tau }^{-}\bar{\nu }$ Anomalies: a General Model Analysis
• Low-energy signatures of the ${\mathrm{PS}}^3$ model: from $B$-physics anomalies to LFV
• Status of the semileptonic $B$ decays and muon g-2 in general 2HDMs with right-handed neutrinos
• Combined explanations of B-physics anomalies: the sterile neutrino solution
• One constraint to kill them all?
• Lepton flavor universality violation without new sources of quark flavor violation
• Generic Loop Effects of New Scalars and Fermions in $b\to s{\ell }^{+}{\ell }^{-}$, $(g-2{)}_{\mu }$ and a Vector-like $4^{\mathrm{th}}$ Generation
• Explaining the $R_K$ and $R_{K^{\ast }}$ anomalies
• Leptoquark toolbox for precision collider studies
• Flavorful leptoquarks at hadron colliders
• Minimal flavor-changing $Z^{\prime }$ models and muon $g-2$ after the $R_{K^{\ast }}$ measurement
• On lepton non-universality in exclusive $b\to s\ell \ell$ decays
• Anomaly-free local horizontal symmetry and anomaly-full rare B-decays
• Flavor Physics and Flavor Anomalies in Minimal Fundamental Partial Compositeness
• Anomalies in Bottom from new physics in Top
• LHCb anomaly and $B$ physics in flavored Z${}^{\prime }$ models with flavored Higgs doublets
• $b\to s{\ell }^{+}{\ell }^{-}$ Transitions in Two-Higgs-Doublet Models
• New light mediators for the $R_K$ and $R_{K^{\ast }}$ puzzles
• Unified Framework for $B$-Anomalies, Muon $g-2$, and Neutrino Masses
• Implications for New Physics in $b\to s\mu \mu$ transitions after recent measurements by Belle and LHCb
• Complete Vector-like Fourth Family and new $\mathrm{U}(1{)}^{\prime }$ for Muon Anomalies
• $U(1{)}_{B_3-3L_{\mu }}$ gauge symmetry as a simple description of $b\to s$ anomalies
• Minimal unified resolution to $R_{K^{(\ast )}}$ and $R(D^{(\ast )})$ anomalies with lepton mixing
• Flavourful $Z^{\prime }$ portal for vector-like neutrino Dark Matter and $R_{K^{(\ast )}}$
• $B$ decay anomalies and dark matter from vectorlike confinement
• Challenges in Semileptonic B Decays
• Combined explanations of $(g-2{)}_{\mu }$, $R_{D^{(\ast )}}$, $R_{K^{(\ast )}}$ anomalies in a two-loop radiative neutrino mass model
• Hadronic and New Physics Contributions to $b\to s$ Transitions
• Explaining $b\to s{\ell }^{+}{\ell }^{-}$ and the Cabibbo Angle Anomaly with a Vector Triplet
• $Z^{\prime }$ models with less-minimal flavour violation
• The CKM parameters in the SMEFT
• A "Vector-like chiral" fourth family to explain muon anomalies
• QCD Improved Matching for Semi-Leptonic B Decays with Leptoquarks
• Flavor anomalies and dark matter in SUSY with an extra U(1)
• Combined Constraints on First Generation Leptoquarks
• Searching for Lepton Flavour (Universality) Violation and Collider Signals from a Singly-Charged Scalar Singlet
• The experimental status of direct searches for exotic physics beyond the standard model at the Large Hadron Collider
• Scalar Leptoquarks in Leptonic Processes
• First-Generation New Physics in Simplified Models: From Low-Energy Parity Violation to the LHC
• Correlating Lepton Flavour (Universality) Violation in $B$ Decays with $\mu \to e\gamma$ using Leptoquarks
• Revisiting R-parity violating interactions as an explanation of the B-physics anomalies
• Proton decay into charged leptons
• Low-energy Effects of Lepton Flavour Universality Violation
• flavio: a Python package for flavour and precision phenomenology in the Standard Model and beyond
• $R_{K^{(\ast )}}$ and related $b\to s\ell \bar{\ell }$ anomalies in minimal flavor violation framework with $Z^{\prime }$ boson
• Global Analysis of Leptophilic Z' Bosons
• Tau Neutrinos in the Next Decade: from GeV to EeV
• Are we overlooking Lepton Flavour Universal New Physics in $b\to s\ell \ell$ ?
• $B$-meson anomalies and Higgs physics in flavored $U(1{)}^{\prime }$ model
• Combined Explanation of the $Z\to b\bar{b}$ Forward-Backward Asymmetry, the Cabibbo Angle Anomaly, $\tau \to \mu \nu \nu$ and $b\to s{\ell }^{+}{\ell }^{-}$ Data
• A clockwork solution to the flavor puzzle
• Collider Constraints on $Z^{\prime }$ Models for Neutral Current $B-$Anomalies
• Impact of the $b\to sll$ anomalies on dark matter physics
• A Common Origin of Neutrino Masses and $R_{D^{(\ast )}}$, $R_{K^{(\ast )}}$ Anomalies
• A minimal $U(1{)}^{\prime }$ extension of MSSM in light of the B decay anomaly
• A Light Higgs at the LHC and the B-Anomalies
• Simplified Models of Flavourful Leptoquarks
• A minimal flavored $U(1{)}^{\prime }$ for $B$-meson anomalies
• Light Resonances and the Low-$q^2$ Bin of $R_{K^{\ast }}$
• The CKM Parameters
• Large $h\to bs$ in generic two-Higgs-doublet models
• Scrutinizing $R$-parity violating interactions in light of $R_{K^{(\ast )}}$ data
• Complete Vector-like Fourth Family with ${\mathrm{U}(1)}^{\prime }$: A Global Analysis
• A chiral SU(4) explanation of the $b\to s$ anomalies
• Flavor Non-universality Gauge Interactions and Anomalies in B-Meson Decays
• $R(K^{(\ast )})$ from dark matter exchange
• Resolving the $(g-2{)}_{\mu }$ and $B$ anomalies with leptoquarks and a dark Higgs boson
• New physics in $b\to s\ell \ell$ decays with complex Wilson coefficients
• Complete Lagrangian and Set of Feynman Rules for Scalar Leptoquarks
• New Physics in Rare B Decays after Moriond 2021
• B anomalies and dark matter: a complex connection
• Top-philic $Z^{\prime }$ Forces at the LHC
• Model independent analysis of New Physics effects on $B_c\to (D_s,D_s^{\ast }){\mu }^{+}{\mu }^{-}$ decay observables
• Revisiting Minimal Lepton Flavour Violation in the Light of Leptonic CP Violation
• B-physics anomalies: The bridge between R-parity violating Supersymmetry and flavoured Dark Matter
• Connecting $b\to s\ell \bar{\ell }$ anomalies to enhanced rare nonleptonic ${\bar{B}}_s^0$ decays in $Z^{\prime }$ model
• Bottom-quark Fusion Processes at the LHC for Probing $Z^{\prime }$ Models and B-meson Decay Anomalies
• Flavor anomalies from asymptotically safe gravity
• New physics in $b\to s{e}^{+}{e}^{-}$?
• The Forward-Backward Asymmetry in $B\to D^{\ast }\ell \nu$: One more hint for Scalar Leptoquarks?
• Common explanation to the $R_{K^{(\ast )}}$, $R_{D^{(\ast )}}$ and ${\epsilon }^{\prime }/\epsilon$ anomalies in a 3HDM+${\nu }_R$ and connections to neutrino physics
• Opportunities for lattice QCD in quark and lepton flavor physics
• Contributions to $b\to s\ell \ell$ Anomalies from $R$-Parity Violating Interactions
• Angular analysis of the rare decay ${\Lambda }_b\to \Lambda (1520)(\to NK){\ell }^{+}{\ell }^{-}$
• Anatomy of a six-parameter fit to the $b\to s{\ell }^{+}{\ell }^{-}$ anomalies
• A gauged horizontal $SU(2)$ symmetry and $R_{K^{(\ast )}}$
• What $R_K$ and $Q_5$ can tell us about New Physics in $b\to s\ell \ell$ transitions?
• The Flavourful Present and Future of 2HDMs at the Collider Energy Frontier
• Identifying a $Z^{\prime }$ behind $b\to s\ell \ell$ anomalies at the LHC
• $R_K$ anomalies and simplified limits on $Z^{\prime }$ models at the LHC
• Angular analysis of $B_s\to f_2^{\prime }(1525)(\to K^{+}{K}^{-}){\mu }^{+}{\mu }^{-}$ decays as a probe to lepton flavor universality violation
• $B$ decay anomalies from nonabelian local horizontal symmetry
• Flavour anomalies and the muon $g-2$ from feebly interacting particles
• Anomalies in $B$ Decays and Muon $g-2$ from Dark Loops
• Correlating Non-Resonant Di-Electron Searches at the LHC to the Cabibbo-Angle Anomaly and Lepton Flavour Universality Violation
• Hadron Collider Sensitivity to Fat Flavourful $Z^{\prime }$s for $R_{K^{(\ast )}}$
• $R_{K^{(\ast )}}$ and $R(D^{(\ast )})$ anomalies resolved with lepton mixing
• Non-minimal $331$ model for Lepton Flavour Universality Violation in $b\to s\ell \ell$ decays
• The strange side of LHCb
• Finite Family Groups for Fermionic and Leptoquark Mixing Patterns
• Anomalies in B mesons decays: A phenomenological approach
• Flavour anomalies from a split dark sector
• Non-universal Z' from SO(10) GUTs with vector-like family and the origin of neutrino masses
• Charged Higgs boson contribution to $B_q^{-}\to \ell \bar{\nu }$ and $\bar{B}\to (P,V)\ell \bar{\nu }$ in a generic two-Higgs doublet model
• Flavour issues in warped custodial models: $B$ anomalies and rare $K$ decays
• Testing Leptoquark and $Z^{\prime }$ Models via $B\to K_1(1270,1400){\mu }^{+}{\mu }^{-}$ Decays
• Anomalies in $b\to s$ transitions and dark matter
• Flavour anomalies: a review
• Implications of the $R_K$ and $R_{K^{\ast }}$ anomalies
• New physics effects in purely leptonic $B_s^{\ast }$ decays
• Observation of $D_s^{+}\to {\eta }^{\prime }{\mu }^{+}{\nu }_{\mu }$, Precision Test of Lepton Flavor Universality with $D_s^{+}\to {\eta }^{(\prime )}{\ell }^{+}{\nu }_{\ell }$, and First Measurements of $D_s^{+}\to {\eta }^{(\prime )}{\mu }^{+}{\nu }_{\mu }$ Decay Dynamics
• One colorful resolution to the neutrino mass generation, three lepton flavor universality anomalies, and the Cabibbo angle anomaly
• Lepton flavor non-universality in the B-sector: a global analyses of various new physics models
• Addendum to: Combined Constraints on First Generation Leptoquarks
• On the decays $B\to K^{(\ast )}+$ leptonium
• B Anomalies and Leptoquarks at the LHC: Beyond the Lepton-Quark Final State
• Some results on Lepton Flavour Universality Violation
• Implication of family non-universal $Z^{\prime }$ model to rare exclusive $b\to s(l\bar{l},\nu \bar{\nu })$ transitions
• Lepton Flavor Violation in a $Z^{\prime }$ model for the $b\to s$ anomalies
• Next-to-Leading-Order QCD Matching for $\Delta F=2$ Processes in Scalar Leptoquark Models
• Studies of Lepton Flavor Violation at the LHC
• Explaining the $R_K$ and $R_{K^{\ast }}$ Anomalies With Right-handed Sneutrino
• Footprints of New Physics in the angular distribution of $B_c\to D_s^{\ast }(\to D_s\gamma ,(D_s\pi )){\ell }^{+}{\ell }^{-}$ decays
• Direct Constraints, Flavor Physics, and Flavor Anomalies in Composite Higgs Models
• Quark masses, CKM angles and Lepton Flavour Universality violation
• Search for the vectorlike leptons in the U(1)${}_X$ model inspired by the $B$-meson decay anomalies
• Leptoquarks in Flavour Physics
• Towards establishing Lepton Flavour Universality violation in $\bar{B}\to {\bar{K}}^{\ast }{\ell }^{+}{\ell }^{-}$ decays
• The fate of $V_1$ vector leptoquarks: the impact of future flavour data
• Implications of light $Z^{\prime }$ on semileptonic $B(B_s)\to T\{K_2^{\ast }(1430)$ $(f_2^{\prime }(1525))\}{\ell }^{+}{\ell }^{-}$ decays at large recoil
• New Physics in $b\to s\ell \ell$ anomalies and its implications for the complementary neutral current decays
• Correlating the CDF $W$-boson mass shift with the $b\to s{\ell }^{+}{\ell }^{-}$ anomalies
• New physics in $\text{b}\to \text{s}$ transitions in the MF331 model
• $B_s$-${\bar{B}}_s$ mixing interplay with $B$ anomalies
• Rare nonleptonic ${\bar{B}}_s^0$ decays as probes of new physics behind $b\to s\mu \bar{\mu }$ anomalies
• $R_{K^{(\ast )}}$ from RPV-SUSY sneutrinos
• Singlet Heavy Fermions as the Origin of B Anomalies in Flavour Changing Neutral Currents
• Using Machine Learning techniques in phenomenological studies in flavour physics
• Dark Matter phenomenology : from simplified WIMP models to refined alternative solutions
• The ${\Lambda }_b\to \Lambda (\to p{\pi }^{-}){\mu }^{+}{\mu }^{-}$ decay in the ${\text{RS}}_c$ model
• Explaining the $b\to s{\ell }^{+}{\ell }^{-}$ anomalies in $Z^{\prime }$ scenarios with top-FCNC couplings
• Anomalies in B mesons decays: Present status and future collider prospects
• Flavor signatures of complex anomalous $tcZ$ couplings
• Discriminating 1D new physics solutions in $b\to s\ell \ell$ decays
• Vector-like Leptons in Light of the Cabibbo-Angle Anomaly
• $\ge 4\mu$ signal from a vector-like lepton decaying to a muon-philic $Z^{\prime }$ boson at the LHC
• A 331 Model for Lepton Flavor Universality Violation in $B$ Decays
• Prospects for rare B decays at Belle II
• Hunt for rare processes and long-lived particles at FCC-ee
• Rare B, D and K decays, radiative and electroweak penguin decays, including constraints on $V_{td}/V_{ts}$ and ${\epsilon }^{\prime }/\epsilon$: Summary of CKM 2018 working group 3
• Search for new physics in $b\to q\ell \ell$ decays
• Lepton Universality Violation by Kaluza-Klein Neutrinos in $b\to sll$ transition
• Theoretical implications of recent heavy flavour measurements at the LHC