Lepton-flavor universality limits in warped space

Abstract

We explore the limits on lepton-flavor universality (LFU) violation in theories where the hierarchy problem is solved by means of a warped extra dimension. In those theories LFU violation, in fermion interaction with Kaluza-Klein modes of gauge bosons, is provided ab initio when different flavor of fermions are differently localized along the extra dimension. As this fact arises from the mass pattern of quarks and leptons, LFU violation is natural in this class of theories. We analyze the experimental data pointing towards LFU violation, as well as the most relevant electroweak and flavor observables, and the LFU tests in the $\mu /e$ and $\tau /\mu$ sectors. We find agreement with $R_{K^{(\ast )}}$ and $R_{D^{(\ast )}}$ data at 95% CL, provided the third generation left-handed fermions are composite ($0.14<c_{b_L}<0.28$ and $0.27<c_{{\tau }_L}<0.33$), and find the absolute limits $R_{K^{(\ast )}}\gtrsim 0.79$ and $R_{D^{(\ast )}}/R_{D^{(\ast )}}^{\mathrm{SM}}\lesssim 1.13$. Moreover we predict $\mathcal{B}(B\to K\nu \bar{\nu })\gtrsim 1.14\times 10^{-5}$ at 95% CL, smaller than the present experimental upper bound but a few times larger than the Standard Model prediction.

6 pages, 4 figures; v2 added references, improved discussion

References in corpus (39)

• A Large Mass Hierarchy from a Small Extra Dimension
• Precision Electroweak Measurements on the Z Resonance
• Test of lepton universality using $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ decays
• Evidence for an excess of B -> D(*) Tau Nu decays
• Test of lepton universality with $B^0\to K^{\ast 0}{\ell }^{+}{\ell }^{-}$ decays
• Measurement of an Excess of B -> D(*) Tau Nu Decays and Implications for Charged Higgs Bosons
• Measurement of the branching ratio of $\bar{B}\to D^{(\ast )}{\tau }^{-}{\bar{\nu }}_{\tau }$ relative to $\bar{B}\to D^{(\ast )}{\ell }^{-}{\bar{\nu }}_{\ell }$ decays with hadronic tagging at Belle
• Measurement of the ratio of branching fractions $\mathcal{B}({\overline{B}}^0\to D^{\ast +}{\tau }^{-}{\overline{\nu }}_{\tau })/\mathcal{B}({\overline{B}}^0\to D^{\ast +}{\mu }^{-}{\overline{\nu }}_{\mu })$
• Measurement of the $\tau$ lepton polarization and $R(D^{\ast })$ in the decay $\bar{B}\to D^{\ast }{\tau }^{-}{\bar{\nu }}_{\tau }$
• On the Standard Model predictions for $R_K$ and $R_{K^{\ast }}$
• 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
• Global analysis of $b\to s\ell \ell$ anomalies
• Precision Tau Physics
• Confronting lepton flavor universality violation in B decays with high-$p_T$ tau lepton searches at LHC
• Flavour physics from an approximate U(2)^3 symmetry
• High-$p_T$ dilepton tails and flavour physics
• Revisiting Lepton Flavour Universality in B Decays
• Search for B --> K(*) nu nubar and invisible quarkonium decays
• On the anomalies in the latest LHCb data
• Simultaneous Explanation of the $R_K$ and $R_{D^{(\ast )}}$ Puzzles: a Model Analysis
• Status of the $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$ anomaly after Moriond 2017
• Search for B -> h(*) nu nubar with the full Belle Y(4S) data sample
• On the Importance of Electroweak Corrections for B Anomalies
• Standard Model predictions for B -> Kll with form factors from lattice QCD
• Lepton-flavor universality violation in $R_K$ and $R_{D^{(\ast )}}$ from warped space
• A Natural origin for the LHCb anomalies
• Soft-Wall Stabilization
• Hadronic uncertainties in $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$: a state-of-the-art analysis
• A 125 GeV composite Higgs boson versus flavour and electroweak precision tests
• Warped Electroweak Breaking Without Custodial Symmetry
• Flavor hierarchies from dynamical scales
• Suppressing Electroweak Precision Observables in 5D Warped Models
• Composite MFV and Beyond
• Search for $B^{+}\to K^{+}{\tau }^{+}{\tau }^{-}$ at the BaBar experiment
• Phenomenology of Non-Custodial Warped Models
• Flavor Phenomenology in General 5D Warped Spaces
• Improving Naturalness in Warped Models with a Heavy Bulk Higgs Boson
• Warped 5D Standard Model Consistent with EWPT
• On light dilaton extensions of the Standard Model

Cited by in corpus (10)

• New Physics in $b\to s{\ell }^{+}{\ell }^{-}$ confronts new data on Lepton Universality
• Cosmological Phase Transitions in Warped Space: Gravitational Waves and Collider Signatures
• Unified explanation of flavor anomalies, radiative neutrino mass and ANITA anomalous events in a vector leptoquark model
• $R_K$ and $R_{K^{\ast }}$ in an Aligned 2HDM with Right-Handed Neutrinos
• Recent $\mathbf{B}$ Physics Anomalies - a First Hint for Compositeness?
• Status of Flavour Maximal Non-minimal Universal Extra Dimension
• Muon $g-2$ and semileptonic $B$ decays in Bélanger-Delaunay-Westhoff model with gauge kinetic mixing
• Monopoles on string-like models and the Coulomb's law
• $B$ anomalies in the nonminimal universal extra dimension model
• Status of new physics in CP violation and rare B decays