Test of lepton universality with ${\Lambda }_b^0\to p{K}^{-}{\ell }^{+}{\ell }^{-}$ decays

Abstract

The ratio of branching fractions of the decays ${\Lambda }_b^0\to p{K}^{-}{e}^{+}{e}^{-}$ and ${\Lambda }_b^0\to p{K}^{-}{\mu }^{+}{\mu }^{-}$, $R_{pK}^{-1}$, is measured for the first time using proton-proton collision data corresponding to an integrated luminosity of 4.7 $f{b}^{-1}$ recorded with the LHCb experiment at center-of-mass energies of 7, 8 and 13 TeV. In the dilepton mass-squared range $0.1<q^2<6.0$ $Ge{V}^2/c^4$ and the $p{K}^{-}$ mass range $m(p{K}^{-})<2600$ $MeV/c^2$, the ratio of branching fractions is measured to be $R_{pK}^{-1}=1.17_{-0.16}^{+0.18}\pm 0.07$, where the first uncertainty is statistical and the second systematic. This is the first test of lepton universality with b baryons and the first observation of the decay ${\Lambda }_b^0\to p{K}^{-}{e}^{+}{e}^{-}$.

arXiv commentAll figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2019-040.html (LHCb public pages)

References in corpus (34)

• PYTHIA 6.4 Physics and Manual
• PYTHIA 6.2 Physics and Manual
• A Brief Introduction to PYTHIA 8.1
• Observation of $J/\psi p$ resonances consistent with pentaquark states in ${\Lambda }_b^0\to J/\psi K^{-}p$ decays
• LHCb Detector Performance
• PHOTOS Monte Carlo: a precision tool for QED corrections in Z and W decays
• Test of lepton universality with $B^0\to K^{\ast 0}{\ell }^{+}{\ell }^{-}$ decays
• New Results on B->pi, K, eta Decay Formfactors from Light-Cone Sum Rules
• B_{d,s}->rho, omega, K*, phi Decay Form Factors from Light-Cone Sum Rules Revisited
• $B\to V{\ell }^{+}{\ell }^{-}$ in the Standard Model from Light-Cone Sum Rules
• Kernel Estimation in High-Energy Physics
• On the Standard Model predictions for $R_K$ and $R_{K^{\ast }}$
• Measurement of the Differential Branching Fraction and Forward-Backword Asymmetry for B->K(*)l+l-
• Search for lepton-universality violation in $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ decays
• Global analysis of $b\to s\ell \ell$ anomalies
• Angular Distributions of B -> K ll Decays
• Efficient, reliable and fast high-level triggering using a bonsai boosted decision tree
• Measurement of Branching Fractions and Rate Asymmetries in the Rare Decays B -> K(*) l+ l-
• Selection and processing of calibration samples to measure the particle identification performance of the LHCb experiment in Run 2
• Reassessing the discovery potential of the $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$ decays in the large-recoil region: SM challenges and BSM opportunities
• Test of lepton-flavor universality in $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$ decays at Belle
• Measurement of angular parameters from the decay ${\mathrm{B}}^0\to {\mathrm{K}}^{\ast 0}{\mu }^{+}{\mu }^{-}$ in proton-proton collisions at $\sqrt{s}=$ 8 TeV
• Status of the $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$ anomaly after Moriond 2017
• Test of lepton flavor universality and search for lepton flavor violation in $B\to K\ell \ell$ decays
• Diagnosing lepton-nonuniversality in $b\to s\ell \ell$
• Bounding wide composite vector resonances at the LHC
• With or without U(2)? Probing non-standard flavor and helicity structures in semileptonic B decays
• Hadronic uncertainties in $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$: a state-of-the-art analysis
• Angular moments of the decay ${\Lambda }_b^0\to \Lambda {\mu }^{+}{\mu }^{-}$ at low hadronic recoil
• Rare dileptonic decays of Λ_b in a quark model
• Measuring the Breaking of Lepton Flavour Universality in $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$
• Observation of the decay ${\Lambda }_b^0\to p{K}^{-}{\mu }^{+}{\mu }^{-}$ and a search for $CP$ violation
• Angular analysis of the rare decay ${\Lambda }_b\to \Lambda (1520)(\to NK){\ell }^{+}{\ell }^{-}$
• Assessing lepton-flavour non-universality from $B\to K^{\ast }\ell \ell$ angular analyses

Cited by in corpus (38)

• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2021
• On the single leptoquark solutions to the $B$-physics anomalies
• Branching fraction measurements of the rare $B_s^0\to \varphi {\mu }^{+}{\mu }^{-}$ and $B_s^0\to f_2^{\prime }(1525){\mu }^{+}{\mu }^{-}$ decays
• Test of lepton universality in $b\to s{\ell }^{+}{\ell }^{-}$ decays
• Measurement of lepton universality parameters in $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ and $B^0\to K^{\ast 0}{\ell }^{+}{\ell }^{-}$ decays
• To (b)e or not to (b)e: No electrons at LHCb
• Tests of lepton universality using $B^0\to K_S^0{\ell }^{+}{\ell }^{-}$ and $B^{+}\to K^{\ast +}{\ell }^{+}{\ell }^{-}$ decays
• Semitauonic $b$-hadron decays: A lepton flavor universality laboratory
• Flavor Anomalies in Heavy Quark Decays
• Measurements of the branching fractions of the semileptonic decays ${\Xi }_c^0\to {\Xi }^{-}{\ell }^{+}{\nu }_{\ell }$ and the asymmetry parameter of ${\Xi }_c^0\to {\Xi }^{-}{\pi }^{+}$
• Search for the rare decays $B_s^0\to e^{+}{e}^{-}$ and $B^0\to e^{+}{e}^{-}$
• Heavy Flavour Physics and CP Violation at LHCb: a Ten-Year Review
• ${\Lambda }_b\to {\Lambda }^{\ast }(1520){\ell }^{+}{\ell }^{-}$ form factors from lattice QCD
• Endpoint Relations for Baryons
• UV physics from IR features: new prospects from top flavor violation
• Flavor Physics at the CEPC: a General Perspective
• Search for rare decays of $D^0$ mesons into two muons
• Search for new phenomena in final states with two leptons and one or no $b$-tagged jets at $\sqrt{s}=13$ TeV using the ATLAS detector
• Prospects for New Physics searches with ${\Lambda }_b\to \Lambda (1520){\ell }^{+}{\ell }^{-}$ decays
• Transition form factors and angular distributions of the ${\mathbf{\Lambda }}_{\mathbf{b}}\to \mathbf{\Lambda }(1520)(\to \mathbf{N}\bar{\mathbf{K}}){\mathbf{\ell }}^{+}{\mathbf{\ell }}^{-}$ decay supported by baryon spectroscopy
• Test of lepton flavour universality with $B_s^0\to \varphi {\ell }^{+}{\ell }^{-}$ decays
• Measurement of the ${\Lambda }_b^0\to \Lambda (1520){\mu }^{+}{\mu }^{-}$ differential branching fraction
• Diffractive Dissociation of Alpha Particles as a Test of Isophobic Short-Range Correlations inside Nuclei
• New Physics in $b\to s\ell \ell$ anomalies and its implications for the complementary neutral current decays
• Towards an amplitude analysis of the decay ${\Lambda }_b^0\to p{K}^{-}\gamma$
• Angular analysis of the rare decay $B_s^0\to \varphi {\mu }^{+}{\mu }^{-}$
• Test of lepton flavour universality with $B^{+}\to K^{+}{\pi }^{+}{\pi }^{-}{\ell }^{+}{\ell }^{-}$ decays
• Assessing Lepton Flavor Universality Violations in Semileptonic Decays
• Implications of new physics in $B\to K_1{\mu }^{+}{\mu }^{-}$ decay processes
• Constraints on new physics from decays of polarized ${\Lambda }_b^0$ baryons at the FCC-ee
• Recent progress in decays of $b$ and $c$ hadrons
• Prospects for $B_c^{+}\to {\tau }^{+}{\nu }_{\tau }$ at FCC-ee
• Heavy quark expansion of ${\Lambda }_b\to {\Lambda }^{\ast }(1520)$ form factors beyond leading order
• Anomalies in the heavy sector
• Flavour Physics at LHCb -- 50 years of the KM paradigm
• Rare decays at LHCb
• Non-parametric and continuous extraction of amplitudes in electroweak penguin decays
• Lepton Flavour Universality tests and Lepton Flavour Violation searches at LHCb