Lett. The analysis technique used to obtain the results presented in this paper is essentially identical to that used to obtain the previous LHCb RK measurement, described in ref. Charpentier,G. Ciezarek,M. Clemencic,J. Closier,V. Coco,P. Collins,T. Colombo,G. Corti,B. Couturier,C. DAmbrosio,P. dArgent,H. Dijkstra,L. Dufour,P. Durante,T. Evans,M. Fo,M. Ferro-Luzzi,R. Forty,M. Frank,C. Frei,W. Funk,S. Gambetta,C. Gaspar,C. Giugliano,E. L. Gkougkousis,E. Govorkova,L. A. Granado Cardoso,T. Gys,C. Haen,J. Haimberger,C. Hasse,M. Hatch,A. M. Hennequin,R. Jacobsson,S. Jakobsen,D. Johnson,B. Jost,N. Jurik,M. Karacson,F. Keizer,R. D. Krawczyk,D. Lacarrere,R. Lindner,B. Malecki,C. Marin Benito,L. Martinazzoli,R. Matev,Z. Mathe,M. Mazurek,M. Mikhasenko,M. Milovanovic,D. S. Mitzel,F. Muheim,M. Mulder,D. Mller,P. Muzzetto,N. Neufeld,P. R. Pais,A. Pearce,M. Pepe Altarelli,M. Petric,F. Pisani,S. Ponce,D. Popov,L. Promberger,P. Roloff,T. Ruf,M. Salomoni,H. Schindler,B. Schmidt,A. Schopper,R. Schwemmer,P. Seyfert,F. Stagni,S. Stahl,M. Szymanski,F. Teubert,E. Thomas,N. Tuning,A. Valassi,C. Vzquez Sierra,K. Wyllie&O. Zenaiev, School of Physics and Astronomy, University of Glasgow, Glasgow, UK, M. Alexander,D. Bobulska,G. Coombs,L. Douglas,L. Eklund,D. A. Friday,I. Longstaff,M. Petric,G. Sarpis,M. Schiller,F. J. P. Soler&P. Spradlin, ICCUB, Universitat de Barcelona, Barcelona, Spain, A. Alfonso Albero,A. Camboni,J. M. Fernandez-tenllado Arribas,P. Garcia Moreno,L. Garrido,P. Gironella Gironell,S. Gomez Fernandez,E. Graugs,J. Mauricio&D. Sanchez Gonzalo, Department of Physics and Astronomy, University of Manchester, Manchester, UK, Z. Aliouche,R. J. Barlow,A. Bitadze,S. Borghi,J. L. Cobbledick,A. Davis,O. The theory predicts that the different charged leptons, the electron, muon and tau . The rJ/ ratio is therefore also computed as a function of different kinematic variables. Use the Previous and Next buttons to navigate the slides or the slide controller buttons at the end to navigate through each slide. Extended Data Fig. One method to search for new physics is to compare measurements of the properties of hadron decays, where hadrons are bound states of quarks, with their SM predictions. The m(K++) mass ranges and the q2 regions used to select the different decay modes are shown in Extended Data Table 1. Angular analysis of the B+K*++ decay. A consistent model-independent interpretation of all these data is possible via a modification of the \(\overline{b}\to \overline{s}\) coupling strength48,49,50,51,52,53,54. The invariant mass of the final state particles, m(K++), is used to discriminate between signal and background contributions, with the signal expected to accumulate around the known mass of the B+ meson. LHCb collaboration et al. Methods A 764, 150155 (2014). The authors declare no competing interests. 4 from a normal distribution stems from the definition of RK. B 753, 424448 (2016). 2. Phys. J. Nikhef National Institute for Subatomic Physics, Amsterdam, Netherlands, R. Aaij,J. S. Butter,K. Carvalho Akiba,S. Ferreres Sole,E. Gabriel,R. E. Geertsema,L. M. Greeven,K. Heijhoff,W. Hulsbergen,D. Hynds,E. Jans,S. Klaver,P. Koppenburg,I. Kostiuk,H. S. Kuindersma,M. Lucio Martinez,V. Lukashenko,A. Mauri,M. Merk,A. Pellegrino,C. Sanchez Gras,M. Schubiger,A. Snoch,N. Tuning,A. Usachov,M. van Beuzekom&M. Veronesi, Physik-Institut, Universitt Zrich, Zrich, Switzerland, C. Abelln Beteta,M. Atzeni,R. Bernet,C. Betancourt,Ia. The B+K++ and B+J/(+)K+ candidates must be triggered by one of the muons, whereas B+K+e+e and B+J/(e+e)K+ candidates must be triggered in one of three ways: by either one of the electrons, by the kaon from the B+ decay or by other particles in the event that are not decay products of the B+ candidate. Straub, D. M. flavio: a python package for flavour and precision phenomenology in the standard model and beyond. The y-axis in each figure shows the number of candidates in an interval of the indicated width. Part. CERN experiment found that beauty quarks not behaving in the way they The theory predicts that the di erent charged leptons, the electron, muon and tau, have identical electroweak interaction strengths. To suppress background, each final-state particle is required to have sizeable pT and to be inconsistent with coming from a PV. A. Bertolin. 08, 098 (2016). Steven D. Bass, Albert De Roeck & Marumi Kado, Nature Physics Aaij, R. et al. The value of q2 is calculated using only the lepton momenta, without imposing any constraint on the m(K++) mass. Google Scholar. J. Instrum. Test of lepton universality in beauty-quark decays - NASA/ADS The theory predicts that the different charged leptons, the electron, muon and tau, have identical electroweak interaction. Combining the uncertainties gives \({R}_{K}=0.84{6}_{-\ 0.041}^{+\ 0.044}\). Test of lepton universality with beauty baryons, RpK Lett. Stanford Libraries' official online search tool for books, media, journals, databases, government documents and more. The results are consistent between the different data-taking periods and with previous LHCbmeasurements37. For the electron modes that dictate the RK precision, this requirement reduces the combinatorial background by approximately 99% while retaining 85% of the signal mode. C 78, 451 (2018). Theor. Phys. The LHCb collaboration et al. J. Bremsstrahlung emission in the decay of particles is simulated using the PHotos software in the default configuration89, which is observed to agree with an independent quantum electrodynamics calculation at the level of 1% (ref. Measurements of branching fractions, rate asymmetries, and angular distributions in the rare decays BK+ and BK*+. Tension with the SM is also seen in the combination of several ratios that test lepton universality in \(\overline{b}\to \overline{c}{\ell }^{+}{\nu }_{\ell }\) transitions55,56,57,58,59,60,61,62,63. Previous measurements have shown a wide range of particle decays are consistent with this principle of lepton universality. Geant4: a simulation toolkit. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. The dominant such background for the non-resonant and resonant modes comes from partially reconstructed B(0,+)K+(,0)e+e and B(0,+)J/(e+e)K+(,0) decays, respectively, where the pion is not included in the B+ candidate. Test of lepton universality in beauty-quark decays. D 95, 035029 (2017). 2016, 65 (2016). ISSN 1745-2481 (online) Predictions for lepton flavor universality violation in rare B decays in models with gauged LL. Eur. Breiman, L., Friedman, J. H., Olshen, R. A., & Stone C. J. Ciuchini, M. et al. Nucl. Phys. The latter also tend to accumulate around specific values of m(K++). Eur. 331, 032023 (2011). The corresponding parameters are then fixed in the fits to the relevant non-resonant modes. Background from other exclusive B-hadron decays requires at least two particles to be misidentified. In the fit for RK, these yields and the efficiencies are incorporated as Gaussian-constraint terms. 12, 040 (2007). The LHCbdetector at the LHC. High. To avoid unconscious bias, the analysis procedure was developed and the cross-checks described below performed before the result for RK was examined. We are indebted to the communities behind the multiple open-source software packages on which we depend. In the fits to non-resonant B+K+e+e candidates, the mass shape of the background from B+J/(e+e)K+ decays with an emitted photon that is not reconstructed is also taken from simulation and, adjusting for the relevant selection efficiency, its yield is constrained to the value from the fit to the resonant mode within its uncertainty. Lett. The systematic uncertainty (Methods) from the choice of signal and background mass-shape models in the fits is estimated by fitting pseudo-experiments with alternative models that still describe the data well. J. The lack of any dependence of the value of \({r}_{J/\psi }/ < {r}_{J/\psi } >\) as a function of B+ pT demonstrates control of the efficiencies. The J/ meson consists of a charm quark and antiquark, \(c\overline{c}\), and is produced resonantly at q2=9.59GeV2c4. For the non-resonant B+K+e+e decays, the systematic uncertainties are dominated by the modelling of the signal and background components used in the fit. The value of RK is found to be consistent in subsets of the data divided on the basis of data-taking period, different selection categories and magnet polarity (Methods). High Energy Phys. Lett. 12, 104 (2020). ADS The y-axis in each figure shows the number of candidates in an interval of the indicated width. Test of the universality of and lepton couplings in W-boson decays with the ATLAS detector, A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery, Search for charged-lepton-flavour violation in Z-boson decays with the ATLAS detector, Evidence for intrinsic charm quarks in the proton, Precise determination of the Phys. The theory predicts that the different charged leptons, the electron, muon and tau, have identical electroweak interaction strengths. You are using a browser version with limited support for CSS. Rev. The value of rJ/ is measured to be 0.9810.020. Lett. In the software trigger, the tracks of the final-state particles are required to form a displaced vertex with good fit quality. For each of the classifiers, a requirement is placed on the output variable to maximize the predicted significance of the non-resonant signal yield. J. The LHCb collaboration et al. & Virto, J. Today at the CERN seminar and at the Rencontres de Blois the LHCb Collaboration presented new tests of lepton universality, one of the basic principles of the Standard Model (SM) of particle physics. J. 178, 852867 (2008).

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