The region between the dashed vertical lines is rejected. Eur. Instrum. D 93, 014028 (2016). Calculation of the SM predictions for the branching fractions of B+K++ and B+K+e+e decays is complicated by the strong nuclear force that binds together the quarks into hadrons, as described by quantum chromodynamics (QCD). This article presents evidence for the breaking of lepton universality in beauty-quark decays, with a significance of 3.1 standard deviations, based on proton-proton collision data collected with the LHCb detector . Measurable quantities can be predicted precisely in the decays of a charged beauty hadron, B +, into a charged kaon, K +, and two charged leptons, + . Measurements of the angular distributions in the decays BK(*)+ at CDF. The B+J/(+)K+ decays are not suppressed and hence have a branching fraction orders of magnitude larger than that of B+K++ decays. This article presents evidence for the breaking of lepton universality in beauty-quark decays, with a significance of 3.1 standard deviations, based on proton-proton collision data collected with the LHCb detector at CERN's Large Hadron Collider. As detailed below, percent-level control of the efficiencies is verified with a direct comparison of the B+J/(e+e)K+ and B+J/(+)K+ branching fractions in the ratio. However, the intervals of the likelihood distribution are found to be the same when estimated with 1/RK as the fit parameter. The value of rJ/ is measured to be 0.9810.020. Test of lepton universality in beauty-quark decays - INSPIRE Rev. The measurements are of processes in which a beauty meson transforms into a strange meson with the emission of either an electron and a positron, or a muon and an antimuon. 3 Resonant candidates invariant mass distributions. This uncertainty includes both statistical and systematic effects, where the latter dominate. Such decays also exhibit some tension with the SM predictions but the extent of residual QCD effects is still the subject of debate3,21,39,40,41,42,43,44,45,46,47. Phys. A. Bertolin. The residual contribution from such decays is considered as a source of systematic uncertainty. Phys. Other experiments should also be able to determine RH ratios, with the Belle II experiment in particular expected to have competitive sensitivity72. Skwarnicki, T. A Study of the Radiative Cascade Transitions between the Upsilon-Prime and Upsilon Resonances. The distributions of the B+ transverse momentum (pT, left) and the ratio rJ/ (right) relative to its average value \(< {r}_{J/\psi } >\) as a function of pT. 2). This is the most precise measurement to date and is consistent with the SM expectation, 1.000.01 (refs. Simulated events are weighted to correct for the imperfect modelling using control channels. The vertical dashed line indicates the SM prediction. Distribution of the invariant mass m(K+e+e) for B+K+e+e candidates. In both cases, for both signal and background, the efficiency of the BDT selection has negligible dependence on m(K++) and q2 in the regions used to determine the event yields. refers to partially reconstructed B hadron decays. Bay,V. Bellee,F. Blanc,S. A. Bouchiba,S. Celani,S. Cholak,M. De Cian,S. Ek-In,L. Ferreira Lopes,E. Graverini,G. Haefeli,D. Hill,V. S. Kirsebom,V. Macko,M. Marinangeli,T. Nakada,T. Nanut,T. D. Nguyen,C. Nguyen-Mau,G. Pietrzyk,F. Redi,A. New physics in bs+ confronts new data on lepton universality. Phys. LHCb explores the beauty of lepton universality | CERN 24, 01025 (2020). 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. Pseudo-experiments are also used to assess the degree of bias originating from the fitting procedure. In the SM description of such processes, these virtual particles include the electroweak force carriers, the , W and Z0 bosons, and the top quark (Fig. In the electron minimum pT spectra, the structure at 2800 MeV/c is related to the trigger threshold. LHCb collaboration et al. 2019, 89 (2019). Agostinelli, S. et al. For the non-resonant candidates, the m(K+e+e)and m(K++)distributions are fitted with a likelihood function that has the B+K++ yield and RK as fit parameters and the resonant decay mode yields incorporated as Gaussian-constraint terms. Eur. Ser. Phys. Due to the small masses of both electrons and muons compared with that of b quarks, this ratio is predicted to be close to unity, except where the value of the dilepton invariant mass-squared (q2) significantly restricts the phase space available to form the two leptons. B. Coelho,F. Desse,F. Machefert,E. M. Niel,P. Robbe,M. H. Schune&G. Wormser, L. Anderlini,A. Bizzeti,G. Graziani,S. Mariani,G. Passaleva&M. Veltri, M. Andreotti,W. Baldini,C. Bozzi,R. Calabrese,M. Fiorini,E. Franzoso,C. Giugliano,P. Griffith,M. Guarise,S. Kotriakhova,E. Luppi,A. Minotti,L. Minzoni,I. Neri,L. L. Pappalardo,B. Passalacqua,B. G. Siddi,I. Slazyk,L. Tomassetti&S. Vecchi, Physikalisches Institut, Ruprecht-Karls-Universitt Heidelberg, Heidelberg, Germany, F. Archilli,S. Bachmann,D. Berninghoff,M. Borsato,G. Frau,D. Gerick,J. P. Grabowski,P. A. Gnther,X. Han,S. Hansmann-Menzemer,J. Hu,R. Kopecna,B. Leverington,P. Li,H. Malygina,J. Lett. The J/ meson consists of a charm quark and antiquark, \(c\overline{c}\), and is produced resonantly at q2=9.59GeV2c4. Aad, G. et al. Nucl. Correlations between different categories of selected events and data-taking periods are taken into account in these constraints. 1 (left). The latest LHCb result is the first test of lepton universality made using the decays of beauty baryonsthree-quark particles containing at least one beauty quark. This effect is accounted for using simulation (Extended Data Figs. For RK the LHCb measurements are in the range 1.1New tests of lepton universality show the same pattern as deviations Angular analysis of \({B}_{d}^{0}\to {K}^{* }{\mu }^{+}{\mu }^{-}\) decays in pp collisions at \(\sqrt{s}=8\) TeV with the ATLAS detector. Prog. Aaij, R. et al. Lett. Mar 22, 2019. Uncertainties on the data points are the combination of statistical and systematic and represent one standard deviation. Test of lepton universality in beauty-quark decays. Phys. The corresponding significance in terms of standard deviations is computed using the inverse Gaussian cumulative distribution function for a one-sided conversion. We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); MOST and NSFC (China); CNRS/IN2P3 (France); BMBF, DFG and MPG (Germany); INFN (Italy); NWO (Netherlands); MNiSW and NCN (Poland); MEN/IFA (Romania); MSHE (Russia); MICINN (Spain); SNSF and SER (Switzerland); NASU (Ukraine); STFC (United Kingdom); DOE NP and NSF (United States). Test of lepton universality in beauty-quark decays - NASA/ADS Kaon and muon candidates are identified using the output of multivariate classifiers that exploit information from the tracking system, the ring-imaging Cherenkov detectors, the calorimeters and the muon chambers. A significant proportion (0.7%) of this uncertainty comes from the limited knowledge of the K spectrum in B(0,+)K+(,0)e+e decays. Jan 2019; PHYS REV LETT; The PVs are reconstructed by searching for space points where an accumulation of track trajectories is observed. oscillation frequency, Probing CP symmetry and weak phases with entangled double-strange baryons, Polarization and entanglement in baryonantibaryon pair production in electronpositron annihilation, The Higgs boson implications and prospects for future discoveries, http://opendata.cern.ch/record/410/files/LHCb-Data-Policy.pdf, https://www.hepdata.net/record/ins1852846?version=1. Gligorov, V. V. & Williams, M. Efficient, reliable and fast high-level triggering using a bonsai boosted decision tree. s Only potentially interesting events, selected using real-time event filters referred to as triggers, are recorded. The particles are required to originate from a common vertex, displaced from the protonproton interaction point, with good vertex-fit quality. Google Scholar. Distribution of the invariant mass mJ/(K++) for resonant candidates in the (left) sample previously analysed11 and (right) the new data sample. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Measurement of \({{{\mathcal{R}}}}(D)\) and \({{{\mathcal{R}}}}({D}^{* })\) with a semileptonic tagging method. Fan,J. Particle physicists have therefore been searching for new physics, that is, new particles and interactions that can explain the SMs shortcomings. In the software trigger, the tracks of the final-state particles are required to form a displaced vertex with good fit quality. The four signal modes are modelled by multiple Gaussian functions with power-law tails on both sides of the peak91,92, although the differing detector response gives different shapes for the electron and muon modes. Uncertainties on the data points are statistical only and represent one standard deviation. This is the most precise measurement of this ratio to date and is compatible with the SM prediction with a P value of 0.10%. D 94, 072007 (2016). 18, 277282 (2022). Huber, P. J. in Robust Estimation of a Location Parameter (eds Kotz S. & Johnson N. L.) 492518 (Springer, 1992). Rev. Introduction In the Standard Model of particle physics (SM), the interactions of the three lepton avours with the gauge bosons exhibit the same coupling strength. A 30, 1530022 (2015). Test of lepton universality using \({\Lambda }_{b}^{0}\to p{K}^{-}{\ell }^{+}{\ell }^{-}\) decays. As the detector signature of each resonant decay is similar to that of its corresponding non-resonant decay, systematic uncertainties that would otherwise dominate the calculation of these efficiencies are suppressed. Sun, Institute of Nuclear Physics, Moscow State University (SINP MSU), Moscow, Russia, I. Belov,A. Berezhnoy,I. V. Gorelov,M. Korolev,A. Leflat,N. Nikitin,D. Savrina&V. Zhukov, Institute of Theoretical and Experimental Physics NRC Kurchatov Institute (ITEP NRC KI), Moscow, Russia, I. Belyaev,A. Danilina,V. Egorychev,D. Golubkov,P. Gorbounov,A. Konoplyannikov,T. Kvaratskheliya,V. Matiunin,T. Ovsiannikova,D. Pereima,D. Savrina,A. Semennikov&A. Smetkina, INFN Laboratori Nazionali di Frascati, Frascati, Italy, G. Bencivenni,L. Calero Diaz,S. Cali,P. Campana,P. Ciambrone,P. De Simone,P. Di Nezza,M. Giovannetti,G. Lanfranchi,G. Morello,M. Palutan,M. Poli Lener,M. Rotondo,M. Santimaria&B. 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Watson, Universit di Modena e Reggio Emilia, Modena, Italy, Department of Physics, University of Oxford, Oxford, UK, M. Bjrn,K. M. Fischer,F. Goncalves Abrantes,B. R. Gruberg Cazon,T. H. Hancock,N. Harnew,M. John,L. Li,S. Malde,R. A. Mohammed,C. H. Murphy,T. Pajero,M. Pili,H. Pullen,V. Renaudin,A. Rollings,L. G. Scantlebury Smead,J. C. Smallwood,F. Suljik,G. Wilkinson&Y. Zhang, Massachusetts Institute of Technology, Cambridge, MA, USA, T. Boettcher,D. C. Craik,O. Kitouni,C. Weisser&M. Williams, National Research University Higher School of Economics, Moscow, Russia, A. Boldyrev,D. Derkach,M. Hushchyn,M. Karpov,A. Maevskiy,F. Ratnikov,A. Ryzhikov&A. Ustyuzhanin, Budker Institute of Nuclear Physics (SB RAS), Novosibirsk, Russia, A. Bondar,S. Eidelman,P. Krokovny,V. Kudryavtsev,T. Maltsev,L. Shekhtman&V. Vorobyev, University of Maryland, College Park, MD, USA, S. Braun,A. D. Fernez,M. Franco Sevilla,P. M. Hamilton,A. Jawahery,W. Parker,Y. Angular analysis of the B0K*0+ decay using 3fb1 of integrated luminosity. Rev. The fits to the non-resonant (resonant) decay modes in different data-taking periods and trigger categories are shown in Extended Data Fig. Energy Phys. The LHCb collaboration et al. Novel Tests of Lepton Universality Boost Evidence for 'New Physics Has a new particle called a 'leptoquark' been spotted at CERN? 10, 075 (2016). Program of Guangzhou (China); RFBR, RSF and Yandex LLC (Russia); GVA, XuntaGal and GENCAT (Spain); the Leverhulme Trust, the Royal Society and UKRI (United Kingdom). Extensions to the SM that aim to address many of its shortfalls predict new virtual particles that could contribute to \(\overline{b}\to \overline{s}\) transitions (Fig. Left: the SM contribution involves the electroweak bosons ,W+ and Z0, and the up-type quarks , \(\bar{c}\) and \(\bar{t}\). Rev. Phys. J. LHCb collaboration, Test of lepton universality in beauty-quark decays, Nature Phys. For decays with H=K+ and H=K*0 such ratios, denoted by RK and RK*0, respectively, have previously been measured by the Large Hadron Collider beauty (LHCb)11,12, Belle13,14 and BaBar15 collaborations. The fitted yields for the resonant and non-resonant decays are given in Extended Data Table 2. Aaij, R. et al. 2 (Extended Data Fig. Lees, J. P. et al. The energy of any such deposit is added to the electron energy that is derived from the measurements made in the tracker. Measurable quantities can be predicted precisely in the decays of a charged beauty hadron, B+, into a charged kaon, K+, and two charged leptons, +. C 79, 840 (2019). Lett. 14, P11023 (2019). The LHCbdetector at the LHC. Lett. We are indebted to the communities behind the multiple open-source software packages on which we depend. The Belle collaboration et al. Rev. Use the Previous and Next buttons to navigate the slides or the slide controller buttons at the end to navigate through each slide. J. The calibrated simulation is used subsequently to obtain the m(K++) mass shape and relative fractions of these background components. Energy Phys. Rev. Clemencic, M. et al. The theory predicts that the different charged leptons, the electron, muon and tau, have identical electroweak interaction strengths. Lees, J. P. et al. The region to the left of the vertical dashed line is rejected. J. The 1.9% uncertainty on the B+J/K+ branching fraction2 gives rise to the dominant systematic uncertainty. The results presented today focus on lepton flavour universality, but the LHCb experiment also studies matter-antimatter differences. Eur. J. 2021, 105 (2021). Distribution of the invariant mass m(J/)(K++) for candidates with electron (left) and muon (right) pairs in the final state for the non-resonant B+K++ signal channels (top) and resonant B+J/(+)K+ decays (bottom). Phys. (Left, with log y-scale) the bremsstrahlung correction to the momentum of the electron is applied, resulting in a tail to the right. 2). The LHCb Collaboration, Test of lepton universality in beauty-quark decays, Nature Physics 18, (2022) 277-282. The B + hadron contains a beauty antiquark, b, and the K + a strange antiquark, s, such that at the quark level the decay involves a b s transition . The weights are calculated by requiring that simulated B+J/(+)K+ events exhibit the same trigger performance as the control data. Eur. Ghez,J. F. Marchand,M.-N. Minard,B. Pietrzyk,B. Quintana,M. Reboud&S. TJampens, Center for High Energy Physics, Tsinghua University, Beijing, China, C. Chen,J. Explore our virtual experience B. Zonneveld, Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele, Romania, L. Cojocariu,A. Ene,L. Giubega,A. Grecu,F. Maciuc,V. Placinta&M. Straticiuc, L. Congedo,M. De Serio,R. A. Fini,A. Palano,M. Pappagallo,A. Pastore&S. Simone, L. Congedo,M. De Serio,M. Pappagallo&S. Simone, Los Alamos National Laboratory (LANL), Los Alamos, NM, USA, J. Crkovsk,C. L. Da Silva,C. T. Dean,J. M. Durham,E. Epple&G. J. Kunde, Van Swinderen Institute, University of Groningen, Groningen, Netherlands, K. De Bruyn,C. J. G. Onderwater&M. van Veghel, Universiteit Maastricht, Maastricht, Netherlands, Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Krakw, Poland, A. Dendek,M. Firlej,T. Fiutowski,M. Idzik,P. Kopciewicz,W. Krupa,O. Madejczyk,M. W. Majewski,J. Moron,A. Oblakowska-Mucha,B. Rachwal,J. Ryzka,K. Swientek&T. Szumlak, F. Dettori,C. Giugliano,G. Manca,R. Oldeman&B. Saitta, Eotvos Lorand University, Budapest, Hungary, Institute for Nuclear Research of the National Academy of Sciences (KINR), Kyiv, Ukraine, V. Dobishuk,S. Koliiev,I. Kostiuk,O. Kot&V. Pugatch, School of Physics, University College Dublin, Dublin, Ireland, A. M. Donohoe,L. Mcconnell,R. McNulty,N. V. Raab&C. B. This estimate takes into account the spectrum of the relevant variables in the non-resonant decay modes of interest and is compatible with the estimated systematic uncertainties on RK. This article presents evidence for the breaking of lepton universality in beauty-quark decays, with a significance of 3.1 standard deviations, based on protonproton collision data collected with the LHCb detector at CERNs Large Hadron Collider. The shape of the B+J/+ background contribution is taken from simulation, but the size with respect to the B+J/K+ mode is constrained using the known ratio of the relevant branching fractions2,94 and efficiencies. An uncertainty comparable to that from the modelling of the signal and background components is induced by the limited sizes of calibration samples. Measurements of the S-wave fraction in B0K++ decays and the B0K*(892)0+ differential branching fraction. The only exception to this is due to the Higgs field, since the leptonHiggs interaction strength gives rise to the differing lepton masses m>m>me. Although this may not be happening, it suggests a new study by the LHCb Collaboration at CERN. Measurement of the ratio of branching fractions \({{{\mathcal{B}}}}({\overline{B}}^{0}\to {D}^{* +}{\tau }^{-}{\overline{\nu }}_{\tau })/{{{\mathcal{B}}}}({\overline{B}}^{0}\to {D}^{* +}{\mu }^{-}{\overline{\nu }}_{\mu })\). Rev. The trigger selection algorithms are based on identifying key characteristics of B hadrons and their decay products, such as high pT final-state particles, and a decay vertex that is significantly displaced from any of the PVs in the event. Recent evidence of a possible fifth force of nature Publishers note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. The performance of the particle identification requirements is then evaluated from the proportion of events in these samples which fulfil the particle identification selection criteria. Classification and Regression Trees (Wadsworth, 1984). The standard model of particle physics currently provides our best description of fundamental particles and their interactions. Energy Phys. 331, 032023 (2011). In the measurement of the rJ/ ratio, the systematic uncertainty is dominated by the imperfect modelling of the B+ production kinematics and the modelling of selection requirements, which have a negligible impact on the RK measurement. No significant trend is observed in the differential determination of rJ/ as a function of any considered variable. A comparable uncertainty arises from the limited size of the calibration samples, with negligible contributions from the calibration of the B+ production kinematics and modelling of the selection and particle-identification efficiencies. J. Hambrock, C., Hiller, G., Schacht, S. & Zwicky, R. BK* form factors from flavor data to QCD and back. and JavaScript. He,W. Huang,H. Liu,X. Lyu,R. Ma,W. Qian,J. Qin,Z. Xiang,J. Xu,Q. Xu,Z. Xu,S. Yang,Y. Yang,Y. Zheng,X. Zhou,Y. Zhou&Z. Zhu, L. Capriotti,A. Carbone,A. Falabella,F. Ferrari,D. Galli,S. Maccolini,D. Manuzzi,U. Marconi,C. Patrignani,S. Perazzini,M. Soares,V. Vagnoni,G. Valenti&S. Zucchelli, L. Capriotti,A. Carbone,F. Ferrari,D. Galli,S. Maccolini,D. Manuzzi,C. Patrignani&S. Zucchelli, INFN Sezione di Roma Tor Vergata, Roma, Italy, Institute Of High Energy Physics (IHEP), Beijing, China, I. Carli,S. Chen,Y. Li,Y. Li,S. Liu,Y. Lu,L. Ma,M. Tobin,J. Wang&Q. Zou, Univ.
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