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Patients' Persistent Symptoms, Clinician Demographics, and Geo-Economic Factors Are Associated with Choice of Therapy for Hypothyroidism by European Thyroid Specialists: The "THESIS" Collaboration. Thyroid 2024; 34:429-441. [PMID: 38368541 DOI: 10.1089/thy.2023.0580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/19/2024]
Abstract
Background: Hypothyroidism is common, however, aspects of its treatment remain controversial. Our survey aimed at documenting treatment choices of European thyroid specialists and exploring how patients' persistent symptoms, clinician demographics, and geo-economic factors relate to treatment choices. Methods: Seventeen thousand two hundred forty-seven thyroid specialists from 28 countries were invited to participate in an online questionnaire survey. The survey included respondent demographic data and treatment choices for hypothyroid patients with persistent symptoms. Geo-economic data for each country were included in the analyses. Results: The response rate was 32.9% (6058 respondents out of 17,247 invitees). Levothyroxine (LT4) was the initial treatment preferred by the majority (98.3%). Persistent symptoms despite normal serum thyrotropin (TSH) while receiving LT4 treatment were reported to affect up to 10.0% of patients by 75.4% of respondents, while 28.4% reported an increasing such trend in the past 5 years. The principal explanations offered for patients' persistent symptoms were psychosocial factors (77.1%), comorbidities (69.2%), and unrealistic patient expectations (61.0%). Combination treatment with LT4+liothyronine (LT3) was chosen by 40.0% of respondents for patients who complained of persistent symptoms despite a normal TSH. This option was selected more frequently by female thyroid specialists, with high-volume practice, working in countries with high gross national income per capita. Conclusions: The perception of patients' dissatisfaction reported by physicians seems lower than that described by hypothyroid patients in previous surveys. LT4+LT3 treatment is used frequently by thyroid specialists in Europe for persistent hypothyroid-like symptoms even if they generally attribute such symptoms to nonendocrine causes and despite the evidence of nonsuperiority of the combined over the LT4 therapy. Pressure by dissatisfied patients on their physicians for LT3-containing treatments is a likely explanation. The association of the therapeutic choices with the clinician demographic characteristics and geo-economic factors in Europe is a novel information and requires further investigation.
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Study of High-Transverse-Momentum Higgs Boson Production in Association with a Vector Boson in the qqbb Final State with the ATLAS Detector. PHYSICAL REVIEW LETTERS 2024; 132:131802. [PMID: 38613283 DOI: 10.1103/physrevlett.132.131802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 02/26/2024] [Indexed: 04/14/2024]
Abstract
This Letter presents the first study of Higgs boson production in association with a vector boson (V=W or Z) in the fully hadronic qqbb final state using data recorded by the ATLAS detector at the LHC in proton-proton collisions at sqrt[s]=13 TeV and corresponding to an integrated luminosity of 137 fb^{-1}. The vector bosons and Higgs bosons are each reconstructed as large-radius jets and tagged using jet substructure techniques. Dedicated tagging algorithms exploiting b-tagging properties are used to identify jets consistent with Higgs bosons decaying into bb[over ¯]. Dominant backgrounds from multijet production are determined directly from the data, and a likelihood fit to the jet mass distribution of Higgs boson candidates is used to extract the number of signal events. The VH production cross section is measured inclusively and differentially in several ranges of Higgs boson transverse momentum: 250-450, 450-650, and greater than 650 GeV. The inclusive signal yield relative to the standard model expectation is observed to be μ=1.4_{-0.9}^{+1.0} and the corresponding cross section is 3.1±1.3(stat)_{-1.4}^{+1.8}(syst) pb.
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Measurement of the Centrality Dependence of the Dijet Yield in p+Pb Collisions at sqrt[s_{NN}]=8.16 TeV with the ATLAS Detector. PHYSICAL REVIEW LETTERS 2024; 132:102301. [PMID: 38518341 DOI: 10.1103/physrevlett.132.102301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/07/2023] [Accepted: 12/04/2023] [Indexed: 03/24/2024]
Abstract
ATLAS measured the centrality dependence of the dijet yield using 165 nb^{-1} of p+Pb data collected at sqrt[s_{NN}]=8.16 TeV in 2016. The event centrality, which reflects the p+Pb impact parameter, is characterized by the total transverse energy registered in the Pb-going side of the forward calorimeter. The central-to-peripheral ratio of the scaled dijet yields, R_{CP}, is evaluated, and the results are presented as a function of variables that reflect the kinematics of the initial hard parton scattering process. The R_{CP} shows a scaling with the Bjorken x of the parton originating from the proton, x_{p}, while no such trend is observed as a function of x_{Pb}. This analysis provides unique input to understanding the role of small proton spatial configurations in p+Pb collisions by covering parton momentum fractions from the valence region down to x_{p}∼10^{-3} and x_{Pb}∼4×10^{-4}.
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Search for New Phenomena in Two-Body Invariant Mass Distributions Using Unsupervised Machine Learning for Anomaly Detection at sqrt[s]=13 TeV with the ATLAS Detector. PHYSICAL REVIEW LETTERS 2024; 132:081801. [PMID: 38457710 DOI: 10.1103/physrevlett.132.081801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 12/13/2023] [Indexed: 03/10/2024]
Abstract
Searches for new resonances are performed using an unsupervised anomaly-detection technique. Events with at least one electron or muon are selected from 140 fb^{-1} of pp collisions at sqrt[s]=13 TeV recorded by ATLAS at the Large Hadron Collider. The approach involves training an autoencoder on data, and subsequently defining anomalous regions based on the reconstruction loss of the decoder. Studies focus on nine invariant mass spectra that contain pairs of objects consisting of one light jet or b jet and either one lepton (e,μ), photon, or second light jet or b jet in the anomalous regions. No significant deviations from the background hypotheses are observed. Limits on contributions from generic Gaussian signals with various widths of the resonance mass are obtained for nine invariant masses in the anomalous regions.
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Observation of WZγ Production in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector. PHYSICAL REVIEW LETTERS 2024; 132:021802. [PMID: 38277610 DOI: 10.1103/physrevlett.132.021802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 09/30/2023] [Accepted: 11/08/2023] [Indexed: 01/28/2024]
Abstract
This Letter reports the observation of WZγ production and a measurement of its cross section using 140.1±1.2 fb^{-1} of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. The WZγ production cross section, with both the W and Z bosons decaying leptonically, pp→WZγ→ℓ^{'}^{±}νℓ^{+}ℓ^{-}γ (ℓ^{(^{'})}=e, μ), is measured in a fiducial phase-space region defined such that the leptons and the photon have high transverse momentum and the photon is isolated. The cross section is found to be 2.01±0.30(stat)±0.16(syst) fb. The corresponding standard model predicted cross section calculated at next-to-leading order in perturbative quantum chromodynamics and at leading order in the electroweak coupling constant is 1.50±0.06 fb. The observed significance of the WZγ signal is 6.3σ, compared with an expected significance of 5.0σ.
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Combined Measurement of the Higgs Boson Mass from the H→γγ and H→ZZ^{*}→4ℓ Decay Channels with the ATLAS Detector Using sqrt[s]=7, 8, and 13 TeV pp Collision Data. PHYSICAL REVIEW LETTERS 2023; 131:251802. [PMID: 38181336 DOI: 10.1103/physrevlett.131.251802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 11/06/2023] [Indexed: 01/07/2024]
Abstract
A measurement of the mass of the Higgs boson combining the H→ZZ^{*}→4ℓ and H→γγ decay channels is presented. The result is based on 140 fb^{-1} of proton-proton collision data collected by the ATLAS detector during LHC run 2 at a center-of-mass energy of 13 TeV combined with the run 1 ATLAS mass measurement, performed at center-of-mass energies of 7 and 8 TeV, yielding a Higgs boson mass of 125.11±0.09(stat)±0.06(syst)=125.11±0.11 GeV. This corresponds to a 0.09% precision achieved on this fundamental parameter of the Standard Model of particle physics.
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Search for Dark Photons in Rare Z Boson Decays with the ATLAS Detector. PHYSICAL REVIEW LETTERS 2023; 131:251801. [PMID: 38181367 DOI: 10.1103/physrevlett.131.251801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 10/11/2023] [Indexed: 01/07/2024]
Abstract
A search for events with a dark photon produced in association with a dark Higgs boson via rare decays of the standard model Z boson is presented, using 139 fb^{-1} of sqrt[s]=13 TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider. The dark boson decays into a pair of dark photons, and at least two of the three dark photons must each decay into a pair of electrons or muons, resulting in at least two same-flavor opposite-charge lepton pairs in the final state. The data are found to be consistent with the background prediction, and upper limits are set on the dark photon's coupling to the dark Higgs boson times the kinetic mixing between the standard model photon and the dark photon, α_{D}ϵ^{2}, in the dark photon mass range of [5, 40] GeV except for the ϒ mass window [8.8, 11.1] GeV. This search explores new parameter space not previously excluded by other experiments.
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Characteristics of specialists treating hypothyroid patients: the "THESIS" collaborative. Front Endocrinol (Lausanne) 2023; 14:1225202. [PMID: 38027187 PMCID: PMC10660282 DOI: 10.3389/fendo.2023.1225202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Thyroid specialists influence how hypothyroid patients are treated, including patients managed in primary care. Given that physician characteristics influence patient care, this study aimed to explore thyroid specialist profiles and associations with geo-economic factors. Methods Thyroid specialists from 28 countries were invited to respond to a questionnaire, Treatment of Hypothyroidism in Europe by Specialists: an International Survey (THESIS). Geographic regions were defined according to the United Nations Statistics Division. The national economic status was estimated using World Bank data on the gross national income per capita (GNI per capita). Results 5,695 valid responses were received (response rate 33·0%). The mean age was 49 years, and 65·0% were female. The proportion of female respondents was lowest in Northern (45·6%) and highest in Eastern Europe (77·2%) (p <0·001). Respondent work volume, university affiliation and private practice differed significantly between countries (p<0·001). Age and GNI per capita were correlated inversely with the proportion of female respondents (p<0·01). GNI per capita was inversely related to the proportion of respondents working exclusively in private practice (p<0·011) and the proportion of respondents who treated >100 patients annually (p<0·01). Discussion THESIS has demonstrated differences in characteristics of thyroid specialists at national and regional levels, strongly associated with GNI per capita. Hypothyroid patients in middle-income countries are more likely to encounter female thyroid specialists working in private practice, with a high workload, compared to high-income countries. Whether these differences influence the quality of care and patient satisfaction is unknown, but merits further study.
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Observation of Single-Top-Quark Production in Association with a Photon Using the ATLAS Detector. PHYSICAL REVIEW LETTERS 2023; 131:181901. [PMID: 37977601 DOI: 10.1103/physrevlett.131.181901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 08/03/2023] [Accepted: 08/09/2023] [Indexed: 11/19/2023]
Abstract
This Letter reports the observation of single top quarks produced together with a photon, which directly probes the electroweak coupling of the top quark. The analysis uses 139 fb^{-1} of 13 TeV proton-proton collision data collected with the ATLAS detector at the Large Hadron Collider. Requiring a photon with transverse momentum larger than 20 GeV and within the detector acceptance, the fiducial cross section is measured to be 688±23(stat) _{-71}^{+75}(syst) fb, to be compared with the standard model prediction of 515_{-42}^{+36} fb at next-to-leading order in QCD.
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Author Correction: A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery. Nature 2023; 623:E5. [PMID: 37853131 PMCID: PMC10620074 DOI: 10.1038/s41586-023-06248-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
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Measurement of Suppression of Large-Radius Jets and Its Dependence on Substructure in Pb+Pb Collisions at sqrt[s_{NN}]=5.02 TeV with the ATLAS Detector. PHYSICAL REVIEW LETTERS 2023; 131:172301. [PMID: 37955510 DOI: 10.1103/physrevlett.131.172301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 05/11/2023] [Accepted: 09/18/2023] [Indexed: 11/14/2023]
Abstract
This letter presents a measurement of the nuclear modification factor of large-radius jets in sqrt[s_{NN}]=5.02 TeV Pb+Pb collisions by the ATLAS experiment. The measurement is performed using 1.72 nb^{-1} and 257 pb^{-1} of Pb+Pb and pp data, respectively. The large-radius jets are reconstructed with the anti-k_{t} algorithm using a radius parameter of R=1.0, by reclustering anti-k_{t} R=0.2 jets, and are measured over the transverse momentum (p_{T}) kinematic range of 158
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Measurement of the Sensitivity of Two-Particle Correlations in pp Collisions to the Presence of Hard Scatterings. PHYSICAL REVIEW LETTERS 2023; 131:162301. [PMID: 37925689 DOI: 10.1103/physrevlett.131.162301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/18/2023] [Accepted: 08/09/2023] [Indexed: 11/07/2023]
Abstract
A key open question in the study of multiparticle production in high-energy pp collisions is the relationship between the "ridge"-i.e., the observed azimuthal correlations between particles in the underlying event that extend over all rapidities-and hard or semihard scattering processes. In particular, it is not known whether jets or their soft fragments are correlated with particles in the underlying event. To address this question, two-particle correlations are measured in pp collisions at sqrt[s]=13 TeV using data collected by the ATLAS experiment at the LHC, with an integrated luminosity of 15.8 pb^{-1}, in two different configurations. In the first case, charged particles associated with jets are excluded from the correlation analysis, while in the second case, correlations are measured between particles within jets and charged particles from the underlying event. Second-order flow coefficients, v_{2}, are presented as a function of event multiplicity and transverse momentum. These measurements show that excluding particles associated with jets does not affect the measured correlations. Moreover, particles associated with jets do not exhibit any significant azimuthal correlations with the underlying event, ruling out hard processes contributing to the ridge.
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Observation of an Excess of Dicharmonium Events in the Four-Muon Final State with the ATLAS Detector. PHYSICAL REVIEW LETTERS 2023; 131:151902. [PMID: 37897770 DOI: 10.1103/physrevlett.131.151902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/31/2023] [Accepted: 08/11/2023] [Indexed: 10/30/2023]
Abstract
A search is made for potential ccc[over ¯]c[over ¯] tetraquarks decaying into a pair of charmonium states in the four muon final state using proton-proton collision data at sqrt[s]=13 TeV, corresponding to an integrated luminosity of 140 fb^{-1} recorded by the ATLAS experiment at LHC. Two decay channels, J/ψ+J/ψ→4μ and J/ψ+ψ(2S)→4μ, are studied. Backgrounds are estimated based on a hybrid approach involving Monte Carlo simulations and data-driven methods. Statistically significant excesses with respect to backgrounds dominated by the single parton scattering are seen in the di-J/ψ channel consistent with a narrow resonance at 6.9 GeV and a broader structure at lower mass. A statistically significant excess is also seen in the J/ψ+ψ(2S) channel. The fitted masses and decay widths of the structures are reported.
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Observation of the γγ→ττ Process in Pb+Pb Collisions and Constraints on the τ-Lepton Anomalous Magnetic Moment with the ATLAS Detector. PHYSICAL REVIEW LETTERS 2023; 131:151802. [PMID: 37897746 DOI: 10.1103/physrevlett.131.151802] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 07/07/2022] [Indexed: 10/30/2023]
Abstract
This Letter reports the observation of τ-lepton-pair production in ultraperipheral lead-lead collisions Pb+Pb→Pb(γγ→ττ)Pb and constraints on the τ-lepton anomalous magnetic moment a_{τ}. The dataset corresponds to an integrated luminosity of 1.44 nb^{-1} of LHC Pb+Pb collisions at sqrt[s_{NN}]=5.02 TeV recorded by the ATLAS experiment in 2018. Selected events contain one muon from a τ-lepton decay, an electron or charged-particle track(s) from the other τ-lepton decay, little additional central-detector activity, and no forward neutrons. The γγ→ττ process is observed in Pb+Pb collisions with a significance exceeding 5 standard deviations and a signal strength of μ_{ττ}=1.03_{-0.05}^{+0.06} assuming the standard model value for a_{τ}. To measure a_{τ}, a template fit to the muon transverse-momentum distribution from τ-lepton candidates is performed, using a dimuon (γγ→μμ) control sample to constrain systematic uncertainties. The observed 95% confidence-level interval for a_{τ} is -0.057
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Strong Constraints on Jet Quenching in Centrality-Dependent p+Pb Collisions at 5.02 TeV from ATLAS. PHYSICAL REVIEW LETTERS 2023; 131:072301. [PMID: 37656838 DOI: 10.1103/physrevlett.131.072301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 10/04/2022] [Accepted: 11/17/2022] [Indexed: 09/03/2023]
Abstract
Jet quenching is the process of color-charged partons losing energy via interactions with quark-gluon plasma droplets created in heavy-ion collisions. The collective expansion of such droplets is well described by viscous hydrodynamics. Similar evidence of collectivity is consistently observed in smaller collision systems, including pp and p+Pb collisions. In contrast, while jet quenching is observed in Pb+Pb collisions, no evidence has been found in these small systems to date, raising fundamental questions about the nature of the system created in these collisions. The ATLAS experiment at the Large Hadron Collider has measured the yield of charged hadrons correlated with reconstructed jets in 0.36 nb^{-1} of p+Pb and 3.6 pb^{-1} of pp collisions at 5.02 TeV. The yields of charged hadrons with p_{T}^{ch}>0.5 GeV near and opposite in azimuth to jets with p_{T}^{jet}>30 or 60 GeV, and the ratios of these yields between p+Pb and pp collisions, I_{pPb}, are reported. The collision centrality of p+Pb events is categorized by the energy deposited by forward neutrons from the struck nucleus. The I_{pPb} values are consistent with unity within a few percent for hadrons with p_{T}^{ch}>4 GeV at all centralities. These data provide new, strong constraints that preclude almost any parton energy loss in central p+Pb collisions.
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Search for Heavy Neutral Leptons in Decays of W Bosons Using a Dilepton Displaced Vertex in sqrt[s]=13 TeV pp Collisions with the ATLAS Detector. PHYSICAL REVIEW LETTERS 2023; 131:061803. [PMID: 37625051 DOI: 10.1103/physrevlett.131.061803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 08/08/2022] [Indexed: 08/27/2023]
Abstract
A search for a long-lived, heavy neutral lepton (N) in 139 fb^{-1} of sqrt[s]=13 TeV pp collision data collected by the ATLAS detector at the Large Hadron Collider is reported. The N is produced via W→Nμ or W→Ne and decays into two charged leptons and a neutrino, forming a displaced vertex. The N mass is used to discriminate between signal and background. No signal is observed, and limits are set on the squared mixing parameters of the N with the left-handed neutrino states for the N mass range 3 GeV
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Test of CP Invariance in Higgs Boson Vector-Boson-Fusion Production Using the H→γγ Channel with the ATLAS Detector. PHYSICAL REVIEW LETTERS 2023; 131:061802. [PMID: 37625052 DOI: 10.1103/physrevlett.131.061802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 02/03/2023] [Indexed: 08/27/2023]
Abstract
A test of CP invariance in Higgs boson production via vector-boson fusion has been performed in the H→γγ channel using 139 fb^{-1} of proton-proton collision data at sqrt[s]=13 TeV collected by the ATLAS detector at the LHC. The optimal observable method is used to probe the CP structure of interactions between the Higgs boson and electroweak gauge bosons, as described by an effective field theory. No sign of CP violation is observed in the data. Constraints are set on the parameters describing the strength of the CP-odd component in the coupling between the Higgs boson and the electroweak gauge bosons in two effective field theory bases: d[over ˜] in the HISZ basis and c_{HW[over ˜]} in the Warsaw basis. The results presented are the most stringent constraints on CP violation in the coupling between Higgs and weak bosons. The 95% C.L. constraint on d[over ˜] is derived for the first time and the 95% C.L. constraint on c_{HW[over ˜]} has been improved by a factor of 5 compared to the previous measurement.
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Observation of WWW Production in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector. PHYSICAL REVIEW LETTERS 2022; 129:061803. [PMID: 36018638 DOI: 10.1103/physrevlett.129.061803] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
This Letter reports the observation of WWW production and a measurement of its cross section using 139 fb^{-1} of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. Events with two same-sign leptons (electrons or muons) and at least two jets, as well as events with three charged leptons, are selected. A multivariate technique is then used to discriminate between signal and background events. Events from WWW production are observed with a significance of 8.0 standard deviations, where the expectation is 5.4 standard deviations. The inclusive WWW production cross section is measured to be 820±100 (stat)±80 (syst) fb, approximately 2.6 standard deviations from the predicted cross section of 511±18 fb calculated at next-to-leading-order QCD and leading-order electroweak accuracy.
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A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery. Nature 2022; 607:52-59. [PMID: 35788192 PMCID: PMC9259483 DOI: 10.1038/s41586-022-04893-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/23/2022] [Indexed: 11/16/2022]
Abstract
The standard model of particle physics1-4 describes the known fundamental particles and forces that make up our Universe, with the exception of gravity. One of the central features of the standard model is a field that permeates all of space and interacts with fundamental particles5-9. The quantum excitation of this field, known as the Higgs field, manifests itself as the Higgs boson, the only fundamental particle with no spin. In 2012, a particle with properties consistent with the Higgs boson of the standard model was observed by the ATLAS and CMS experiments at the Large Hadron Collider at CERN10,11. Since then, more than 30 times as many Higgs bosons have been recorded by the ATLAS experiment, enabling much more precise measurements and new tests of the theory. Here, on the basis of this larger dataset, we combine an unprecedented number of production and decay processes of the Higgs boson to scrutinize its interactions with elementary particles. Interactions with gluons, photons, and W and Z bosons-the carriers of the strong, electromagnetic and weak forces-are studied in detail. Interactions with three third-generation matter particles (bottom (b) and top (t) quarks, and tau leptons (τ)) are well measured and indications of interactions with a second-generation particle (muons, μ) are emerging. These tests reveal that the Higgs boson discovered ten years ago is remarkably consistent with the predictions of the theory and provide stringent constraints on many models of new phenomena beyond the standard model.
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Search for Lepton-Flavor Violation in Z-Boson Decays with τ Leptons with the ATLAS Detector. PHYSICAL REVIEW LETTERS 2021; 127:271801. [PMID: 35061407 DOI: 10.1103/physrevlett.127.271801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 10/05/2021] [Indexed: 06/14/2023]
Abstract
A search for lepton-flavor-violating Z→eτ and Z→μτ decays with pp collision data recorded by the ATLAS detector at the LHC is presented. This analysis uses 139 fb^{-1} of Run 2 pp collisions at sqrt[s]=13 TeV and is combined with the results of a similar ATLAS search in the final state in which the τ lepton decays hadronically, using the same data set as well as Run 1 data. The addition of leptonically decaying τ leptons significantly improves the sensitivity reach for Z→ℓτ decays. The Z→ℓτ branching fractions are constrained in this analysis to B(Z→eτ)<7.0×10^{-6} and B(Z→μτ)<7.2×10^{-6} at 95% confidence level. The combination with the previously published analyses sets the strongest constraints to date: B(Z→eτ)<5.0×10^{-6} and B(Z→μτ)<6.5×10^{-6} at 95% confidence level.
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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. PHYSICAL REVIEW LETTERS 2021; 127:141801. [PMID: 34652194 DOI: 10.1103/physrevlett.127.141801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
A search for new phenomena is presented in final states with two leptons and one or no b-tagged jets. The event selection requires the two leptons to have opposite charge, the same flavor (electrons or muons), and a large invariant mass. The analysis is based on the full run-2 proton-proton collision dataset recorded at a center-of-mass energy of sqrt[s]=13 TeV by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 139 fb^{-1}. No significant deviation from the expected background is observed in the data. Inspired by the B-meson decay anomalies, a four-fermion contact interaction between two quarks (b, s) and two leptons (ee or μμ) is used as a benchmark signal model, which is characterized by the energy scale and coupling, Λ and g_{*}, respectively. Contact interactions with Λ/g_{*} lower than 2.0 (2.4) TeV are excluded for electrons (muons) at the 95% confidence level, still far below the value that is favored by the B-meson decay anomalies. Model-independent limits are set as a function of the minimum dilepton invariant mass, which allow the results to be reinterpreted in various signal scenarios.
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A registry for patients with chronic hypoparathyroidism in Russian adults. Endocr Connect 2020; 9:627-636. [PMID: 32580149 PMCID: PMC7424359 DOI: 10.1530/ec-20-0219] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 06/04/2020] [Indexed: 12/28/2022]
Abstract
Hypoparathyroidism and pseudohypoparathyroidism are rare endocrine disorders, characterized by low serum calcium due to inappropriate parathyroid hormone (PTH) levels or resistance to its action. There is little epidemiological information regarding chronic hypoparathyroidism in Russia. This study aims to build a registry database of Russian patients with chronic hypoparathyroidism who were referred for hospital treatment in order to conduct initial analysis of clinical presentations and hospital management. The Italian registry model was taken to be able to integrate our data in the future. Two hundred patients with hypoparathyroidism (n = 194) and pseudohypoparathyroidism (n = 6) were enrolled over 2 years (2017-2019). The most frequent cause of hypoparathyroidism was neck surgery (82.5%, mostly females), followed by idiopathic hypoparathyroidism (10%), syndromic forms of genetic hypoparathyroidism (4.5%) and forms of defective PTH action (3%). Calcium supplements and alfacalcidol were prescribed in most cases. However, a minority of patients (n = 6) needed to receive teriparatide as the only way to maintain calcium levels and to prevent symptoms of hypocalcemia. Consequently, substitution treatment with parathyroid hormone should be available in certain cases of hypoparathyroidism. This database will be useful to estimate the potential requirement for recombinant PTH in Russia and standards for clinical and therapeutic approaches.
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2012 ETA Guidelines: The Use of L-T4 + L-T3 in the Treatment of Hypothyroidism. Eur Thyroid J 2012; 1:55-71. [PMID: 24782999 PMCID: PMC3821467 DOI: 10.1159/000339444] [Citation(s) in RCA: 237] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 05/07/2012] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Data suggest symptoms of hypothyroidism persist in 5-10% of levothyroxine (L-T4)-treated hypothyroid patients with normal serum thyrotrophin (TSH). The use of L-T4 + liothyronine (L-T3) combination therapy in such patients is controversial. The ETA nominated a task force to review the topic and formulate guidelines in this area. METHODS Task force members developed a list of relevant topics. Recommendations on each topic are based on a systematic literature search, discussions within the task force, and comments from the European Thyroid Association (ETA) membership at large. RESULTS SUGGESTED EXPLANATIONS FOR PERSISTING SYMPTOMS INCLUDE: awareness of a chronic disease, presence of associated autoimmune diseases, thyroid autoimmunity per se, and inadequacy of L-T4 treatment to restore physiological thyroxine (T4) and triiodothyronine (T3) concentrations in serum and tissues. There is insufficient evidence that L-T4 + L-T3 combination therapy is better than L-T4 monotherapy, and it is recommended that L-T4 monotherapy remains the standard treatment of hypothyroidism. L-T4 + L-T3 combination therapy might be considered as an experimental approach in compliant L-T4-treated hypothyroid patients who have persistent complaints despite serum TSH values within the reference range, provided they have previously received support to deal with the chronic nature of their disease, and associated autoimmune diseases have been excluded. Treatment should only be instituted by accredited internists/endocrinologists, and discontinued if no improvement is experienced after 3 months. It is suggested to start combination therapy in an L-T4/L-T3 dose ratio between 13:1 and 20:1 by weight (L-T4 once daily, and the daily L-T3 dose in two doses). Currently available combined preparations all have an L-T4/L-T3 dose ratio of less than 13:1, and are not recommended. Close monitoring is indicated, aiming not only to normalize serum TSH and free T4 but also normal serum free T4/free T3 ratios. Suggestions are made for further research. CONCLUSION L-T4 + L-T3 combination therapy should be considered solely as an experimental treatment modality. The present guidelines are offered to enhance its safety and to counter its indiscriminate use.
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Analysis of extended human leukocyte antigen haplotype association with Addison's disease in three populations. Eur J Endocrinol 2007; 157:757-61. [PMID: 18057383 DOI: 10.1530/eje-07-0290] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Addison's disease is an organ-specific autoimmune disorder with a polygenic background. The aim of the study was to identify non-class II human leukocyte antigen (HLA) susceptibility genes for Addison's disease. DESIGN AND METHODS Addison's disease patients from three European populations were analysed for selected HLA-DR-DQ alleles and for 11 microsatellite markers covering approximately 4 Mb over the HLA region. Subjects were 69 patients with Addison's disease from Estonia (24), Finland (14) and Russia (31). Consecutively recruited healthy newborns from the same geographical regions were used as controls (269 Estonian, 1000 Finnish and 413 Russian). Association measures for HLA-DRB1, DQB1, DQA1 and 11 microsatellites between D6S273 and D6S2223 were taken. A low-resolution full-house typing was used for HLA class II genes, while microsatellite markers were studied using fluorescence-based DNA fragment sizing technology. RESULTS We confirmed that the HLA-DR3-DQ2 and the DQB1*0302-DRB1*0404 haplotypes confer disease susceptibility. In Russian patients, we also found an increase of DRB1*0403 allele, combined with DQB1*0305 allele in three out of six cases (P<0.0001). Analysis of 11 microsatellite markers including STR MICA confirmed the strong linkage in DR3-DQ2 haplotypes but DRB1*0404-DQB1*0302 haplotypes were diverse. MICA5.1 allele was found in 22 out of 24 Estonian patients, but results from Finnish and Russian patients did not support its independent role in disease susceptibility. CONCLUSION HLA-DRB1*0403 was identified as a novel susceptibility allele for Addison's disease. Additionally, we found no evidence of a non-class II HLA disease susceptibility locus; however, the HLA-DR3-DQ2 haplotype appeared more conserved in patient groups with high DR-DQ2 frequencies.
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Abstract
To assess the prevalence of thyroid disorders in a region with mild iodine deficiency, this study was undertaken in a randomized sample of pregnant women during different gestational periods. Evaluations were performed in 215 women: thyroid ultrasound scanning, thyroid stimulating hormone (TSH), free thyroxine (T4) and thyroid peroxidase (TPO) antibodies. At the time of participation in the study, some women (90/215) had been receiving 150-200 micrograms iodine. Hypothyroidism was found in four women (1.86%). Positive TPO antibodies were seen in 34 of 215 women (15.8%), and TPO antibody level over 150 mU/l was found in 9.8% (21/215). There was no significant difference between TSH levels in women with positive or negative TPO antibodies. There were no differences in TSH level between the women receiving and those not receiving iodine prophylaxis. The prevalence of goiter in 211 euthyroid women was found to be 24.2% (51/211). in the group with iodine prophylaxis, thyroid volume was found to be significantly lower (t = 2.5; p = 0.02) than in women who had not received it, or had started it during the second trimester. By comparison of history data on the prevalence of aborted pregnancy between the group with positive (26.5%; 9/34) and the group with negative TPO antibodies (14.3%; 26/181), no significant differences were found. We conclude that, in mild iodine deficiency, pregnancy is related to a high risk of goiter, which can be prevented by iodine prophylaxis. TPO antibody carrier status in pregnant women is probably not associated with a significant risk of thyroid dysfunction or spontaneous abortion.
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Abstract
We have studied two-body charmless decays of the B meson into the final states rho(0)rho(0), K(*0)rho(0), K(*0)K(*0), K(*0)K(*0), K(*+)rho(0), K(*+)K(*0), and K(*+)K(*-) using only decay modes with charged daughter particles. Using 9.7x10(6) BB pairs collected with the CLEO detector, we place 90% confidence level upper limits on the branching fractions (1.4-14.1)x10(-5), depending on final state and polarization.
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Search for the familon via B(+/-) --> pi+/-X(0), B(+/-) --> K(+/-)X(0), and B(0) --> K(0)(S)X(0) decays. PHYSICAL REVIEW LETTERS 2001; 87:271801. [PMID: 11800872 DOI: 10.1103/physrevlett.87.271801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2001] [Indexed: 05/23/2023]
Abstract
We have searched for the two-body decay of the B meson to a light pseudoscalar meson h = pi(+/-),K+/-,K(0)(S) and a massless neutral feebly interacting particle X(0) such as the familon, the Nambu-Goldstone boson associated with a spontaneously broken global family symmetry. We find no significant signal by analyzing a data sample containing 9.7x10(6) BBbar mesons collected with the CLEO detector at the Cornell Electron Storage Ring, and set 90% C.L. upper limits italicB(B(+/-) --> h(+/-)X(0)) = 4.9x10(-5) and italicB(B(0) --> K(0)(S)X(0)) = 5.3x10(-5). These limits correspond to a lower bound of approximately 10(8) GeV on the family symmetry breaking scale with vector coupling involving the third generation of quarks.
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Hadronic mass moments in inclusive semileptonic B meson decays. PHYSICAL REVIEW LETTERS 2001; 87:251808. [PMID: 11736567 DOI: 10.1103/physrevlett.87.251808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2001] [Indexed: 05/23/2023]
Abstract
We have measured the first and second moments of the hadronic mass-squared distribution in B-->X(c)l nu, for P(lepton)>1.5 GeV/c. We find <M(2)(X)-M macro(2)(D)> = 0.251+/-0.066 GeV(2), <(M(2)(X)-<M(2)(X)>)(2)> = 0.576+/-0.170 GeV(4), where M macro(D) is the spin-averaged D meson mass. From that first moment and the first moment of the photon energy spectrum in b-->s gamma, we find the heavy quark effective theory parameter lambda(1) (in the modified minimal subtraction renormalization scheme, to order 1/M(3)(B) and beta(0)alpha(2)(s)) to be -0.24+/-0.11 GeV(2). Using these first moments and the B semileptonic width, and assuming parton-hadron duality, we obtain absolute value of V(cb) = 0.0404+/-0.0013.
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Branching fraction and photon energy spectrum for b --> s gamma. PHYSICAL REVIEW LETTERS 2001; 87:251807. [PMID: 11736566 DOI: 10.1103/physrevlett.87.251807] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2001] [Indexed: 05/23/2023]
Abstract
We have measured the branching fraction and photon energy spectrum for the radiative penguin process b-->s gamma. We find Beta(b-->s gamma) = (3.21+/-0.43+/-0.27(+0.18)(-0.10))x10(-4), where the errors are statistical, systematic, and from theory corrections. We obtain first and second moments of the photon energy spectrum above 2.0 GeV, <E( gamma)> = 2.346+/-0.032+/-0.011 GeV, and <E(2)(gamma)>-<E(gamma)>(2) = 0.0226+/-0.0066+/-0.0020 GeV(2), where the errors are statistical and systematic. From the first moment, we obtain (in the modified minimal subtraction renormalization scheme, to order 1/M(3)(B) and beta(0)alpha(2)(s)) the heavy quark effective theory parameter Lambda = 0.35+/-0.08+/-0.10 GeV.
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Novel AIRE mutations and P450 cytochrome autoantibodies in Central and Eastern European patients with APECED. Hum Mutat 2001; 18:225-32. [PMID: 11524733 DOI: 10.1002/humu.1178] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare recessive disorder that results in several autoimmune diseases due to the mutations in the AIRE (autoimmune regulator) gene. APECED patients develop several autoimmune endocrine disorders and are characterized by the high titer autoantibodies to organ-specific antigens such as the steroidogenic P450 cytochromes. So far, 38 mutations have been identified in the AIRE gene. We report here the genetic and autoantibody analysis of 27 APECED patients of Eastern and Central European origins and one Egyptian patient. From 54 analyzed APECED chromosomes, eight mutations were detected, four of which (T16M, W78R, IVS1_IVS4, 30-53dup23bp) are novel. The most prevalent reason for APECED in these populations was the occurrence of R257X (36 chromosomes) that has been described earlier as a common and recurrent mutation in several other populations. The analysis of humoral immunity to steroidogenic P450 cytochromes by the immunoblotting of E. coli expressed antigens in the 18 APECED patients showed that 67%, 44%, and 61% of the Eastern and Central European APECED patients had autoantibodies to P450c17, P450c21, and P450scc, respectively.
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Rate measurement of D(0)-->K+pi(-)pi(0) and constraints on D(0) -- D(0) mixing. PHYSICAL REVIEW LETTERS 2001; 87:071802. [PMID: 11497880 DOI: 10.1103/physrevlett.87.071802] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2001] [Indexed: 05/23/2023]
Abstract
We present an observation and time-integrated rate measurement of the decay D(0)-->K(+)pi(-)pi(0) produced in 9 fb(-1) of e(+)e(-) collisions near the Upsilon(4S) resonance. The signal is inconsistent with an upward fluctuation of the background by 4.9 standard deviations. We measured the time-integrated rate of D(0)-->K(+)pi(-)pi(0) normalized to the rate of D(0)-->K(+)pi(-)pi(0) to be 0.0043(+0.0011)(-0.0010) (stat)+/-0.0007 (syst). This decay can be produced by doubly Cabibbo-suppressed decays or by the D(0) evolving into a D(0) through mixing, followed by a Cabibbo-favored decay to K(+)pi(-)pi(0). We also found the CP asymmetry A = (9(+25)(-22))% be consistent with zero.
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Experimental investigation of the two-photon widths of the chi(c0) and the chi(c2) mesons. PHYSICAL REVIEW LETTERS 2001; 87:061801. [PMID: 11497821 DOI: 10.1103/physrevlett.87.061801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2001] [Indexed: 05/23/2023]
Abstract
Using 12.7 fb(-1) of data collected with the CLEO detector at CESR, we observed two-photon production of the cc states chi(c0) and chi(c2) in their decay to pi(+)pi(-)pi(+)pi(-). We measured gamma(gammagamma)(chi(c))xB(chi(c)-->pi(+)pi(-)pi(+)pi(-)) to be 75+/-13(stat)+/-8(syst) eV for the chi(c0) and 6.4+/-1.8(stat)+/-0.8(syst) eV for the chi(c2), implying gamma(gammagamma)(chi(c0)) = 3.76+/-0.65(stat)+/-0.41(syst)+/-1.69(br) keV and gamma(gammagamma)(chi(c2)) = 0.53+/-0.15(stat)+/-0.06(syst)+/-0.22(br) keV. Also, cancellation of dominant experimental and theoretical uncertainties permits a precise comparison of gamma(gammagamma)(chi(c0))/gamma(gammagamma)(chi(c2)), evaluated to be 7.4+/-2.4(stat)+/-0.5(syst)+/-0.9(br), with QCD-based predictions.
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35
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Bounds on the CP asymmetry in b --> sgamma decays. PHYSICAL REVIEW LETTERS 2001; 86:5661-5665. [PMID: 11415327 DOI: 10.1103/physrevlett.86.5661] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2000] [Indexed: 05/23/2023]
Abstract
We have measured the CP asymmetry A(CP) identical with[gamma(b-->sgamma)-gammab-->sgamma)]/[gamma(b-->sgamma)+gamma(b-->sgamma)] to be A(CP) = (-0.079+/-0.108+/-0.022) (1.0+/-0.030), implying that, at 90% confidence level, A(CP) lies between -0.27 and +0.10. These limits rule out some extreme non-standard-model predictions, but are consistent with most, as well as with the standard model.
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Bounds on the CP asymmetry in like-sign dileptons from B(0)B*(0) meson decays. PHYSICAL REVIEW LETTERS 2001; 86:5000-5003. [PMID: 11384405 DOI: 10.1103/physrevlett.86.5000] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2001] [Indexed: 05/23/2023]
Abstract
We have measured the charge asymmetry in like-sign dilepton yields from B(0)B*(0) meson decays using the CLEO detector at the Cornell Electron Storage Ring. We find a(0)(ll) identical with[N(l(+)l(+))-N(l(-)l(-))]/[N(l(+)l(+))+N(l(-)l(-))] = +0.013+/-0.050+/-0.005. We combine this result with a previous, independent measurement and obtain Re(epsilon(B))/(1+ the absolute value of epsilon(B)(2)) = +0.0035+/-0.0103+/-0.0015 (uncertainties are statistical and systematic, respectively) for the CP impurity parameter, epsilon(B).
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Study of tau decays to six pions and a neutrino. PHYSICAL REVIEW LETTERS 2001; 86:4467-4471. [PMID: 11384261 DOI: 10.1103/physrevlett.86.4467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2000] [Indexed: 05/23/2023]
Abstract
The tau decays to six-pion final states have been studied with the CLEO detector at the Cornell Electron Storage Ring. The measured branching fractions are B(tau(-)-->2pi(-)pi(+)3pi(0)nu(tau)) = (2.2+/-0.3+/-0.4)x10(-4) and B(tau(-)-->3pi(-)2pi(+)pi(0)nu(tau)) = (1.7+/-0.2+/-0.2)x10(-4). A search for substructure in these decays shows that they are saturated by intermediate states with eta or omega mesons. We present the first observation of the decay tau(-)-->2pi(-)pi(+)omega(nu)tau and the branching fraction is measured to be (1.2+/-0.2+/-0.1)x10(-4). The measured branching fractions are in good agreement with the isospin expectations but somewhat below the conserved-vector-current predictions.
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Observation of new states decaying into Lambda+(c)pi(-)pi(+). PHYSICAL REVIEW LETTERS 2001; 86:4479-4482. [PMID: 11384263 DOI: 10.1103/physrevlett.86.4479] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2000] [Indexed: 05/23/2023]
Abstract
Using 13.7 fb(-1) of data recorded by the CLEO detector at the Cornell Electron Storage Ring, we investigate the spectrum of charmed baryons which decay into Lambda+(c)pi(-)pi(+) and are more massive than the Lambda+(c)(2625) baryon. We find evidence for two new states: one is broad and has an invariant mass roughly 480 MeV above that of the Lambda+(c) baryon; the other is narrow with an invariant mass of 596+/-1+/-2 MeV above the Lambda+(c) mass.
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Evidence of New States Decaying into Xi(*)(c)pi. PHYSICAL REVIEW LETTERS 2001; 86:4243-4246. [PMID: 11328145 DOI: 10.1103/physrevlett.86.4243] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2000] [Indexed: 05/23/2023]
Abstract
Using 13.7 fb(-1) of data recorded by the CLEO detector at Cornell Electron Storage Ring, we report evidence of two new charmed baryons: one decaying into Xi(0')(c)pi(+) with the subsequent decay Xi(0')(c)-->Xi(0)(c)gamma, and its isospin partner decaying into Xi(+')(c)pi(-) followed by Xi(+')(c)-->Xi(+)(c)gamma. We measure the following mass differences for the two states: M(Xi(0)(c)gammapi(+))-M(Xi(0)(c)) = 318.2+/-1.3+/-2.9 MeV and M(Xi(+)(c)gammapi(-))-M(Xi(+)(c)) = 324.0+/-1.3+/-3.0 MeV. We interpret these new states as the J(P) = 1 / 2(-) Xi(c1) particles, the charmed-strange analogs of the Lambda(+)(c1)(2593).
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Observation of B --> phiK and B --> phiK*. PHYSICAL REVIEW LETTERS 2001; 86:3718-3721. [PMID: 11329307 DOI: 10.1103/physrevlett.86.3718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2001] [Indexed: 05/23/2023]
Abstract
We have studied two-body charmless hadronic decays of B mesons into the final states straight phiK and phiK(*). Using 9.7 million B&Bmacr; pairs collected with the CLEO II detector, we observe the decays B- --> phiK- and B0--> phiK(*0) with the following branching fractions: B(B--->phiK-) = (5.5(+2.1)(-1.8)+/-0.6)x10(-6) and B(B0--> phiK(*0)) = (11.5(+4.5+1.8)(-3.7-1.7))x10(-6). We also see evidence for the decays B0-->phiK0 and B---> phiK(*-). However, since the statistical significance is not overwhelming for these modes, we determine upper limits of <12.3x10(-6) and <22.5x10(-6) ( 90% confidence level), respectively.
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Observation of the Omega(0)(c) Charmed Baryon at CLEO. PHYSICAL REVIEW LETTERS 2001; 86:3730-3734. [PMID: 11329310 DOI: 10.1103/physrevlett.86.3730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2000] [Indexed: 05/23/2023]
Abstract
The CLEO experiment at the CESR collider has used 13.7 fb(-1) of data to search for the production of the Omega(0)(c) (css ground state) in e(+)e(-) collisions at square root of (s) approximately 10.6 GeV. The modes used to study the Omega(0)(c) are Omega(-)pi(+), Omega(-)pi(+)pi(0), Xi-K-pi(+)pi(+), Xi0K-pi(+), and Omega(-)pi(+)pi(+)pi(-). We observe a signal of 40.4+/-9.0(stat) events at a mass of 2694.6+/-2.6(stat)+/-1.9(syst) MeV/c(2), for all modes combined.
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Search for B --> tau(nu) and B --> K(nu)nu. PHYSICAL REVIEW LETTERS 2001; 86:2950-2954. [PMID: 11290080 DOI: 10.1103/physrevlett.86.2950] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2000] [Indexed: 05/23/2023]
Abstract
We report results of a search for B-->tau(nu) in a sample of 9.7 x 10(6) charged B meson decays. We exclusively reconstruct the companion B decay to suppress background. We set an upper limit on the branching fraction B(B-->tau(nu))<8.4 x 10(-4) at 90% confidence level. We also establish B(B+/--->K+/-nu(nu))<2.4 x 10(-4) at 90% confidence level.
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Measurement of the relative branching fraction of upsilon(4S) to charged and neutral B-meson pairs. PHYSICAL REVIEW LETTERS 2001; 86:2737-2741. [PMID: 11290027 DOI: 10.1103/physrevlett.86.2737] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2000] [Indexed: 05/23/2023]
Abstract
We analyze 9.7x10(6) B_B pairs recorded with the CLEO detector to determine the production ratio of charged to neutral B-meson pairs produced at the Upsilon(4S) resonance. We measure the rates for B0-->J/psiK((*)0) and B+-->J/psiK((*)+) decays and use the world-average B-meson lifetime ratio to extract the relative widths f(+-) / f(00) = gamma(Upsilon(4S)-->B+B-) / gamma(Upsilon(4S)-->B0 B-0)) = 1.04+/-0.07(stat)+/-0.04(syst). With the assumption that f(+-)+f(00) = 1, we obtain f(00) = 0.49+/-0.02(stat)+/-0.01(syst) and f(+-) = 0.51+/-0.02(stat)+/-0.01(syst). This production ratio and its uncertainty apply to all exclusive B-meson branching fractions measured at the Upsilon(4S) resonance.
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First observation of the decays B(0) --> D(*-)p_p pi+ and B(0) --> D(*-)p_n. PHYSICAL REVIEW LETTERS 2001; 86:2732-2736. [PMID: 11290026 DOI: 10.1103/physrevlett.86.2732] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2000] [Indexed: 05/23/2023]
Abstract
We report the first observation of exclusive decays of the type B-->D(*)N_NX, where N is a nucleon. Using a sample of 9.7x10(6)B_B pairs collected with the CLEO detector operating at the Cornell Electron Storage Ring, we measure the branching fractions B(B0-->D(*-)p_p pi(+)) = (6.5(+1.3)(-1.2)+/-1.0)x10(-4) and B(B0-->D(*-)p_n) = (14.5(+3.4)(-3.0)+/-2.7)x10(-4). Antineutrons are identified by their annihilation in the CsI electromagnetic calorimeter.
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Measurement of the lambda(+)(c) lifetime. PHYSICAL REVIEW LETTERS 2001; 86:2232-2236. [PMID: 11289897 DOI: 10.1103/physrevlett.86.2232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2000] [Indexed: 05/23/2023]
Abstract
The Lambda+c lifetime is measured using 9.0 fb(-1) of e+e- annihilation data collected on or just below the Upsilon(4S) resonance with the CLEO II.V detector at CESR. Using an unbinned maximum likelihood fit, the Lambda+c lifetime is measured to be 179.6+/-6.9(stat)+/-4.4(syst) fs. The precision of this colliding beam measurement is comparable to other measurements, which are based on fixed-target experiments, with different systematic uncertainties.
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First observation of the sigma(*+)(c) baryon and a new measurement of the sigma(*+)(c) mass. PHYSICAL REVIEW LETTERS 2001; 86:1167-1170. [PMID: 11178035 DOI: 10.1103/physrevlett.86.1167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2000] [Indexed: 05/23/2023]
Abstract
Using data recorded with the CLEO II and CLEO II.V detector configurations at the Cornell Electron Storage Rings, we report the first observation and mass measurement of the Sigma(*+)(c) charmed baryon, and an updated measurement of the mass of the Sigma(+)(c) baryon. We find M(Sigma(*+)(c))-M(Lambda(+)(c)) = (231.0+/-1.1+/-2.0) MeV, and M(Sigma(+)(c))-M(Lambda(+)(c)) = (166.4+/-0.2+/-0.3) MeV, where the errors are statistical and systematic, respectively.
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Study of B Decays to Charmonium States: B-->eta(c)K and B --> chi(c0)K. PHYSICAL REVIEW LETTERS 2001; 86:30-34. [PMID: 11136086 DOI: 10.1103/physrevlett.86.30] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2000] [Indexed: 05/23/2023]
Abstract
In a sample of 9.66x10(6)B&Bmacr; pairs collected with the CLEO detector we make the first observation of B decays to an eta(c) and a kaon. We measure branching fractions B(B+-->eta(c)K+) = (0.69(+0.26)(-0.21)+/-0.08+/-0.20)x10(-3) and B(B degrees -->eta(c)K degrees ) = (1.09(+0.55)(-0.42)+/-0.12+/-0.31)x10(-3), where the first error is statistical, the second is systematic, and the third is from the eta(c) branching fraction uncertainty. From these we extract the eta(c) decay constant in the factorization approximation, f(eta(c)) = 335+/-75 MeV. We also search for B decays to a chi(c0) and a kaon. No evidence for a signal is found and we set 90% C.L. upper limits: B(B+-->chi(c0)K+)<4.8x10(-4) and B(B degrees -->chi(c0)K degrees )<5.0x10(-4).
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Measurements of the mass, total width, and two-photon partial width of the eta(c) meson. PHYSICAL REVIEW LETTERS 2000; 85:3095-3099. [PMID: 11019275 DOI: 10.1103/physrevlett.85.3095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2000] [Indexed: 05/23/2023]
Abstract
Using 13.4 fb(-1) of data collected with the CLEO detector at the Cornell Electron Storage Ring, we have observed 300 events for the two-photon production of ground-state pseudoscalar charmonium in the decay eta(c)-->K(0)(S)K-/+pi(+/-). We have measured the eta(c) mass to be [2980.4+/-2.3 (stat)+/-0.6 (syst)] MeV and its full width as [27.0+/-5.8 (stat)+/-1.4 (syst)] MeV. We have determined the two-photon partial width of the eta(c) meson to be [7.6+/-0.8 (stat)+/-0.4 (syst)+/-2.3 (br)] keV, with the last uncertainty associated with the decay branching fraction.
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Study of charmless hadronic B meson decays to pseudoscalar-vector final states. PHYSICAL REVIEW LETTERS 2000; 85:2881-2885. [PMID: 11005959 DOI: 10.1103/physrevlett.85.2881] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2000] [Indexed: 05/23/2023]
Abstract
We report results of searches for charmless hadronic B meson decays to pseudoscalar( pi(+/-), K+/-, pi(0), or K(0)(S))-vector( rho, K(*), or omega) final states. By using 9.7x10(6) BB pairs collected with the CLEO detector, we report the first observation of B(-)--->pi(-)rho(0), B(0)-->pi(+/-)rho(-/+), and B(-)-->pi(-)omega, which are expected to be dominated by hadronic b-->u transitions. The measured branching fractions are (10.4(+3.3)(-3.4)+/-2.1)x10(-6), (27.6(+8.4)(-7.4)+/-4.2)x10(-6), and (11.3(+3.3)(-2.9)+/-1. 4)x10(-6), respectively. Branching fraction upper limits are set for all of the other decay modes investigated.
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Two-body B meson decays to eta and eta('): observation of B --> eta K*. PHYSICAL REVIEW LETTERS 2000; 85:520-524. [PMID: 10991330 DOI: 10.1103/physrevlett.85.520] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/1999] [Indexed: 05/23/2023]
Abstract
In a sample of 19 x 10(6) produced B mesons, we have observed the decays B-->eta K(*) and improved our previous measurements of B-->eta'K. The branching fractions we measure for these decay modes are B(B+-->eta K(*+)) = (26.4(+9.6)(-8.2)+/-3.3)x10(-6), B(B(0)-->eta K(*0)) = (13.8(+5.5)(-4.6)+/-1.6)x10(-6), B(B(+)-->eta'K(+) = (80(+10)(-9)+/-7)x10(-6), and B(B(0)-->eta'K0) = (89(+18)(-16)+/-9)x10(-6). We have searched with comparable sensitivity for related decays and report upper limits for these branching fractions.
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