Measurement of the ratio of branching fractions $\mathcal{B}(B_c^{+}\to J/\psi {\tau }^{+}{\nu }_{\tau })$/$\mathcal{B}(B_c^{+}\to J/\psi {\mu }^{+}{\nu }_{\mu })$

Abstract

A measurement is reported of the ratio of branching fractions $\mathcal{R}(J/\psi )=\mathcal{B}(B_c^{+}\to J/\psi {\tau }^{+}{\nu }_{\tau })/\mathcal{B}(B_c^{+}\to J/\psi {\mu }^{+}{\nu }_{\mu })$, where the ${\tau }^{+}$ lepton is identified in the decay mode ${\tau }^{+}\to {\mu }^{+}{\nu }_{\mu }{\overline{\nu }}_{\tau }$. This analysis uses a sample of proton-proton collision data corresponding to 3.0${\mathrm{fb}}^{-1}$ of integrated luminosity recorded with the LHCb experiment at center-of-mass energies $7\mathrm{TeV}$ and $8\mathrm{TeV}$. A signal is found for the decay $B_c^{+}\to J/\psi {\tau }^{+}{\nu }_{\tau }$ at a significance of 3 standard deviations, corrected for systematic uncertainty, and the ratio of the branching fractions is measured to be $\mathcal{R}(J/\psi )=0.71\pm 0.17(\mathrm{stat})\pm 0.18(\mathrm{syst})$. This result lies within 2 standard deviations above the range of existing predictions in the Standard Model.

All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2017-035.html

References in corpus (11)

• PYTHIA 6.4 Physics and Manual
• Test of lepton universality using $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ decays
• 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
• Addressing the LHC flavour anomalies with horizontal gauge symmetries
• Test of Lepton Flavor Universality by the measurement of the $B^0\to D^{\ast -}{\tau }^{+}{\nu }_{\tau }$ branching fraction using three-prong $\tau$ decays
• Exclusive semileptonic and nonleptonic decays of the Bc meson
• Measurement of the $\tau$ lepton polarization and $R(D^{\ast })$ in the decay $\bar{B}\to D^{\ast }{\tau }^{-}{\bar{\nu }}_{\tau }$ with one-prong hadronic $\tau$ decays at Belle
• Study of exclusive semileptonic and nonleptonic decays of $B_c^{-}$ in a nonrelativistic quark model
• Reweighting with Boosted Decision Trees
• $B_c$ to P-Wave Charmonia Transitions in Covariant Light-Front Approach
• Exclusive Decays and Lifetime of B_c Meson in QCD sum rules

Cited by in corpus (166)

• Test of lepton universality in beauty-quark decays
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2021
• $B$ Meson Anomalies in a Pati-Salam Model within the Randall-Sundrum Background
• Importance of Loop Effects in Explaining the Accumulated Evidence for New Physics in B Decays with a Vector Leptoquark
• Scalar leptoquarks from GUT to accommodate the $B$-physics anomalies
• Review of Lepton Universality tests in B decays
• On the single leptoquark solutions to the $B$-physics anomalies
• The Mono-Tau Menace: From $B$ Decays to High-$p_T$ Tails
• Precise predictions of charmed-bottom hadrons from lattice QCD
• Impact of polarization observables and $B_c\to \tau \nu$ on new physics explanations of the $b\to c\tau \nu$ anomaly
• Searching for New Physics with $b\to s{\tau }^{+}{\tau }^{-}$ processes
• Combined Explanations of the $b\to s{\mu }^{+}{\mu }^{-}$ and $b\to c{\tau }^{-}\bar{\nu }$ Anomalies: a General Model Analysis
• Addendum to "Impact of polarization observables and $B_c\to \tau \nu$ on new physics explanations of the $b\to c\tau \nu$ anomaly"
• Footprints of New Physics in $b\to c\tau \nu$ Transitions
• Third-family quark-lepton unification with a fundamental composite Higgs
• Addressing $R_{D^{(\ast )}}$, $R_{K^{(\ast )}}$, muon $g-2$ and ANITA anomalies in a minimal $R$-parity violating supersymmetric framework
• A Model of Muon Anomalies
• Measurement of the ratios of branching fractions $\mathcal{R}(D^{\ast })$ and $\mathcal{R}(D^0)$
• $R(J/\psi )$ and $B_c^{-}\to J/\psi {\ell }^{-}{\bar{\nu }}_{\ell }$ Lepton Flavor Universality Violating Observables from Lattice QCD
• Semitauonic $b$-hadron decays: A lepton flavor universality laboratory
• Combined explanations of $(g-2{)}_{\mu }$, $R_{D^{(\ast )}}$, $R_{K^{(\ast )}}$ anomalies in a two-loop radiative neutrino mass model
• Search for singly and pair-produced leptoquarks coupling to third-generation fermions in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• $R_2$ as a single leptoquark solution to $R_{D^{(\ast )}}$ and $R_{K^{(\ast )}}$
• The decays $B_c\to J/\psi +\bar{\ell }{\nu }_{\ell }$ and $B_c\to J/\psi +\pi (K)$ in covariant confined quark model
• B-meson charged current anomalies: the post-Moriond status
• The role of right-handed neutrinos in $b\to c\tau \bar{\nu }$ anomalies
• Unified explanation of flavor anomalies, radiative neutrino mass and ANITA anomalous events in a vector leptoquark model
• $B_c\to J/\psi$ Form Factors for the full $q^2$ range from Lattice QCD
• Flavor Anomalies in Heavy Quark Decays
• A Common Origin of Neutrino Masses and $R_{D^{(\ast )}}$, $R_{K^{(\ast )}}$ Anomalies
• Asymmetry Observables and the Origin of $R_{D^{(\ast )}}$ Anomalies
• Charged current $b\to c\tau {\bar{\nu }}_{\tau }$ anomalies in a general $W^{\prime }$ boson scenario
• Investigation of Effects of New Physics in ${\Lambda }_b\to {\Lambda }_c\tau {\bar{\nu }}_{\tau }$ Decay
• Revisit to the $b\to c\tau \nu$ transition: in and beyond the SM
• Impact of ${\Lambda }_b\to {\Lambda }_c\tau \nu$ measurement on New Physics in $b\to cl\nu$ transitions
• Unified SU(4) theory for the $R_{D^{(\ast )}}$ and $R_{K^{(\ast )}}$ anomalies
• Solutions to $R_D$-$R_{D^{\ast }}$ in light of Belle 2019 data
• Inclusive nonresonant multilepton probes of new phenomena at $\sqrt{s}=$ 13 TeV
• Probing new physics in semileptonic ${\Lambda }_b$ decays
• Standard Model prediction of the $B_c$ lifetime
• Measurement of the $B_c^{-}$ meson production fraction and asymmetry in 7 and 13 TeV $pp$ collisions
• Seeking leptoquarks in IceCube
• Beyond $\mathcal{R}(D^{(\ast )})$ with the general 2HDM-III for $b\to c\tau \nu$
• Lepton flavor universality violation in semileptonic tree level weak transitions
• Correlating Tauonic B Decays to the Neutron EDM via a Scalar Leptoquark
• Semileptonic decays $B_c\to ({\eta }_c,J/\psi )l{\bar{\nu }}_l$ in the "PQCD + Lattice" approach
• Phenomenology of $b\to c\tau \bar{\nu }$ decays in a scalar leptoquark model
• Towards ruling out the charged Higgs interpretation of the $R_{D^{(\ast )}}$ anomaly
• Global fit to $b\to c\tau \nu$ anomalies as of Spring 2024
• Probing New Physics with $\bar{B}\to \rho (770){\ell }^{-}{\bar{\nu }}_{\ell }$ and $\bar{B}\to a_1(1260){\ell }^{-}{\bar{\nu }}_{\ell }$
• Heavy Flavour Physics and CP Violation at LHCb: a Ten-Year Review
• Search for new phenomena in $pp$ collisions in final states with tau leptons, $b$-jets, and missing transverse momentum with the ATLAS detector
• Model independent investigation of the $R_{J/\psi ,{\eta }_c}$ and ratios of decay widths of semileptonic $B_c$ decays into a P-wave charmonium
• B-physics anomalies: The bridge between R-parity violating Supersymmetry and flavoured Dark Matter
• Resolution of $R_D$/$R_{D^{\ast }}$ puzzle
• Review of Semileptonic $B$ Anomalies
• Maximizing the Impact of New Physics in $b\to c\tau \nu$ Anomalies
• $B_s\to D_s^{\ast }$ Form Factors for the full $q^2$ range from Lattice QCD
• Boosting vector leptoquark searches with boosted tops
• CP Violation in ${\bar{B}}^0\to D^{\ast +}{\mu }^{-}{\bar{\nu }}_{\mu }$
• Precision Model-Independent Bounds from Global Analysis of $b\to c\ell \nu$ Form Factors
• Relativistic description of the ${\Xi }_b$ baryon semileptonic decays
• Precision measurement of the W boson decay branching fractions in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Model-Independent Determination of $B_c^{+}\to {\eta }_c{\ell }^{+}\nu$ Form Factors
• Probing heavy charged fermions at $e^{+}{e}^{-}$ collider using the Optimal Observable Technique
• A Complete Framework for Tau Polarimetry in $B\to D^{(\ast )}\tau \nu$ Decays
• Non-minimal $331$ model for Lepton Flavour Universality Violation in $b\to s\ell \ell$ decays
• Lepton Flavor Universality tests through angular observables of $\overline{B}\to D^{(\ast )}\ell \overline{\nu }$ decay modes
• $R_{K^{(\ast )}}$ and $R(D^{(\ast )})$ anomalies resolved with lepton mixing
• Analysing the charged scalar boson contribution to the charged-current $B$ meson anomalies
• Heavy + heavy and heavy + light pseudoscalar to vector semileptonic transitions
• Combined explanations of $B$-physics anomalies, $(g-2{)}_{e,\mu }$ and neutrino masses by scalar leptoquarks
• Semileptonic $B_c\to {\eta }_c,J/\psi$ transitions
• Tests of the Standard Model in $B\to D\ell {\nu }_{\ell }$, $B\to D^{\ast }\ell {\nu }_{\ell }$ and $B_c\to J/\psi \ell {\nu }_{\ell }$
• Phenomenology of ${\Xi }_b\to {\Xi }_c\tau \nu$ decays
• Role of $B_c^{+}\to B_{s,d}^{(\ast )}\bar{\ell }{\nu }_{\ell }$ in the Standard Model and in the search for BSM signals
• $B_c$ excitations at LHC experiments
• Prospects for $B_c^{+}$ and $B^{+}\to {\tau }^{+}{\nu }_{\tau }$ at FCC-ee
• ${\Lambda }_b\to {\Lambda }_c$ Form Factors from QCD Light-Cone Sum Rules
• Light dark matter, rare $B$ decays with missing energy in $L_{\mu }-L_{\tau }$ model with a scalar leptoquark
• Semileptonic decays of $B^{(\ast )}$, $D^{(\ast )}$ into $\nu l$ and pseudoscalar or vector mesons
• Implication of $R_{D^{(\ast )}}$ anomalies on semileptonic decays of ${\Sigma }_b$ and ${\Omega }_b$ baryons
• 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
• Signatures of complex new physics in $b\to c\tau \bar{\nu }$ transitions
• Observation of the decay $D^0\to K^{-}{\pi }^{+}{e}^{+}{e}^{-}$
• Impact of vector new physics couplings on $B_s\to (K,K^{\ast })\tau \nu$ and $B\to \pi \tau \nu$ decays
• Study of the $B_c^{+}$ decays into charmonia and three light hadrons
• Right-handed interactions in puzzling $B$-decays
• B Anomalies and Leptoquarks at the LHC: Beyond the Lepton-Quark Final State
• Properties of excited $B_c$ states in QCD
• Lepton mass effects in exclusive semileptonic $B_c$-meson decays
• Flavor Physics at the CEPC: a General Perspective
• $\bar{B}\to D^{(\ast )}\ell \bar{X}$ decays in effective field theory with massive right-handed neutrinos
• Scrutinizing New Physics in Semi-leptonic $B_c\to J/\psi \tau \nu$ Decay
• Implication of $b\to c\tau \nu$ flavor anomalies on $B_s\to D_s^{\ast }\tau \nu$ decay observables
• Looking for $B\to X_s{\ell }^{+}{\ell }^{-}$ in non-minimal Universal Extra Dimensional model
• Study of $B_c$$\to$$J/\psi V$ and $B_c^{\ast }$$\to$${\eta }_{c}V$ decays within the QCD factorization
• Probing new physics in semileptonic ${\Sigma }_b$ and ${\Omega }_b$ decays
• $D^{\ast }$ Polarization as an Additional Constraint on New Physics in the $b\to c\tau {\bar{\nu }}_{\tau }$ Transition
• The PQCD approach towards to next-to-leading order: a short review
• ${\bar{B}}_c\to {\eta }_c$, ${\bar{B}}_c\to J/\psi$ and $\bar{B}\to D^{(\ast )}$ semileptonic decays including new physics
• Semileptonic decays of $B_c$ meson to $P$-wave charmonium states
• Relativistic calculations of $R(D^{(\ast )})$, $R(D_s^{(\ast )})$, $R({\eta }_c)$ and $R(J/\psi )$
• Systematic analysis of the form factors of $B_c\to {\eta }_c$, $J/\psi$ and corresponding weak decays
• Next-to-leading order QCD calculation of $B_c$ to charmonium tensor form factors
• Measuring CP violation in $b\to c{\tau }^{-}{\bar{\nu }}_{\tau }$ using excited charm mesons
• $b\to c\tau \bar{\nu }$ decays in supersymmetry with $R$-parity violation
• New physics effects on ${\Lambda }_b\to {\Lambda }_c^{\ast }\tau {\bar{\nu }}_{\tau }$ decays
• Scouring meson decays for true muonium
• Interplay of the charged Higgs effects in $R_{D^{(\ast )}}$, $b\to s{\ell }^{+}{\ell }^{-}$ and $W$-mass
• A Light shed on Lepton Flavor Universality in B decays
• Leptoquarks in Flavour Physics
• A Challenge to Lepton Universality in B Meson Decays
• Predictions of $B_c\to (D,D^{\ast })l\nu$ decay observables in the standard model
• The role of multi-parton interactions in doubly-heavy hadron production
• $B_c\to J/\psi$ helicity form factors and the $B_c^{+}\to J/\psi +(P,V,{\ell }^{+}{\nu }_{\ell })$ decays
• The $B\to \pi \ell {\nu }_{\ell }$ semileptonic decay within the LCSR approach under heavy quark effective field theory
• Probing New Physics in light of recent developments in $b\to c\ell \nu$ transitions
• ${\tau }_{B_s}/{\tau }_{B_d}$ and $\Delta {\Gamma }_s$ confront new physics in $b\to s\tau \tau$
• Baryonic heavy-to-light form factors induced by tensor current in light-front approach
• Semileptonic $B_c$ decays to $P-$wave charmonium and the nature of ${\chi }_{c1}(3872)$
• Semileptonic Decay of $B_c$ to ${\eta }_c$ and $J/\psi$ on the Light Front
• New physics in the angular distribution of $B_c^{-}\to J/\psi (\to {\mu }^{+}{\mu }^{-}){\tau }^{-}(\to {\pi }^{-}{\nu }_{\tau }){\bar{\nu }}_{\tau }$ decay
• Test of lepton flavor universality with measurements of $R(D^{+})$ and $R(D^{\ast +})$ using semileptonic $B$ tagging at the Belle II experiment
• Extra gauge bosons and lepton flavor universality violation in ${\rm Y}$ and $B$ meson decays
• Singlet vector leptoquark model facing recent LHCb and BABAR measurements
• Impact of $b\to c$ measurements on ${\Lambda }_b\to p\tau \bar{\nu }$ decay in $U_1$ leptoquark model
• Search for leptoquark pair production decaying into $t{e}^{-}\bar{t}{e}^{+}$ or $t{\mu }^{-}\bar{t}{\mu }^{+}$ in multi-lepton final states in $pp$ collisions at 13 TeV with the ATLAS detector
• Analysis of $b\to c\tau {\bar{\nu }}_{\tau }$ anomalies using weak effective Hamiltonian with complex couplings
• $B_c$ to $A$ Transition Form Factors and Semileptonic Decays in Self-consistent Covariant Light-front Approach
• Scalar dark matter, Neutrino mass and Leptogenesis in a $\mathrm{U}(1{)}_{\mathrm{B}-\mathrm{L}}$ model
• Search for pair production of scalar and vector leptoquarks decaying to muons and bottom quarks in proton-proton collisions at $\sqrt{s}$ = 13 TeV
• Test of lepton flavor universality in semileptonic B${}_{\text{c}}^{+}$ meson decays in proton-proton collisions at $\sqrt{s}$ = 13 TeV
• Semileptonic baryon decays ${\Xi }_b\to {\Xi }_c{\ell }^{-}{\bar{\nu }}_{\ell }$ in perturbative QCD
• Angular distribution as an effective probe of new physics in semi-hadronic three-body meson decays
• $B_c^{\ast }$ meson parameters and radiative decay width within the covariant confined quark model
• Testing Lepton Flavour Universality in ${\rm Y}(4S)$ Decays
• Probing the R-parity violating supersymmetric effects in $B_c\to J/\psi {\ell }^{-}{\bar{\nu }}_{\ell },{\eta }_c{\ell }^{-}{\bar{\nu }}_{\ell }$ and ${\Lambda }_b\to {\Lambda }_c{\ell }^{-}{\bar{\nu }}_{\ell }$ decays
• Exploring the role of new physics in $b\to u\tau \bar{\nu }$ decays
• Angular analysis of $\bar{B}\to D_2^{\ast }(\to D\pi )\ell \bar{\nu }$ decay and new physics
• Lepton Flavor Violating $B\to K_2^{\ast }(1430){\mu }^{\pm }{\tau }^{\mp }$ Decays
• Visible energy and angular distributions of the charged particle from the $\tau -$decay in $b\to c\tau (\mu {\bar{\nu }}_{\mu }{\nu }_{\tau },\pi {\nu }_{\tau },\rho {\nu }_{\tau }){\bar{\nu }}_{\tau }$ reactions
• Assessing Lepton Flavor Universality Violations in Semileptonic Decays
• Flavour anomalies meet flavour symmetry
• Status of G2HDM with right handed neutrino coupling in the light of $b\to c\tau \nu$ anomalies
• Measurement of the ratio of the B${}_{\mathrm{c}}^{+}$ $\to$ J/$\psi$${\tau }^{+}{\nu }_{\tau }$ and B${}_{\mathrm{c}}^{+}$ $\to$ J/$\psi$ ${\mu }^{+}{\nu }_{\mu }$ branching fractions using three-prong $\tau$ lepton decays
• Decay $B_c^{+}\to D_{(s)}^{(\ast )+}{\ell }^{+}{\ell }^{-}$ within covariant confined quark model
• Implications of new physics in $B\to K_1{\mu }^{+}{\mu }^{-}$ decay processes
• Study of angular observables in exclusive semileptonic $B_c$ decays
• Recent progress in decays of $b$ and $c$ hadrons
• Addressing the $R_{\tau /\mu ,e}\left(D^{(\ast )}\right)$ puzzle through New Physics four-fermion operators and their impact on ${\Lambda }_b\to {\Lambda }_c\tau {\bar{\nu }}_{\tau }$ decay
• Inclusive quasielastic (anti-)neutrino nucleus scattering within the Standard Model and beyond
• Anomalies in Weak Decays of Hadrons Containing a b Quark
• Resolving $R_D$ and $R_{D^{\ast }}$ anomalies
• Hint of a new scalar interaction in LHCb data?
• Phenomenological study of a gauged $L_{\mu }-L_{\tau }$ model with a scalar leptoquark
• Prospects for $B_c^{+}\to {\tau }^{+}{\nu }_{\tau }$ at FCC-ee
• Flavour Physics at LHCb -- 50 years of the KM paradigm
• A model to accommodate the $B$-physics anomalies
• 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
• ${\eta }_c$ leading-twist distribution amplitude and the $B_c\to {\eta }_c\ell {\bar{\nu }}_{\ell }$ semileptonic decays using QCD Sum Rules
• Probing New Physics and CP Violation in ${\nu }_{\tau }n\to {\Lambda }_c{\tau }^{-}({\pi }^{-}{\nu }_{\tau })$ and ${\bar{\nu }}_{\tau }p\to \Lambda {\tau }^{+}({\pi }^{+}{\bar{\nu }}_{\tau })$
• The Angular Observables of ${\Lambda }_b\to {\Lambda }_c(\to {\Lambda }^0{\pi }^{+}){\tau }^{-}(\to {\pi }^{-}{\nu }_{\tau }){\bar{\nu }}_{\tau }$ within the Paradigm of FCCC Anomalies
• Anomalies in the heavy sector