496 research outputs found

    Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

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    Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a ZZ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 <pT<100< p_{\textrm{T}} < 100 GeV and in the pseudorapidity range 2.5<η<42.5 < \eta < 4. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb1^{-1}. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages

    Study of the BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

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    The decay BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} is studied in proton-proton collisions at a center-of-mass energy of s=13\sqrt{s}=13 TeV using data corresponding to an integrated luminosity of 5 fb1\mathrm{fb}^{-1} collected by the LHCb experiment. In the Λc+K\Lambda_{c}^+ K^{-} system, the Ξc(2930)0\Xi_{c}(2930)^{0} state observed at the BaBar and Belle experiments is resolved into two narrower states, Ξc(2923)0\Xi_{c}(2923)^{0} and Ξc(2939)0\Xi_{c}(2939)^{0}, whose masses and widths are measured to be m(Ξc(2923)0)=2924.5±0.4±1.1MeV,m(Ξc(2939)0)=2938.5±0.9±2.3MeV,Γ(Ξc(2923)0)=0004.8±0.9±1.5MeV,Γ(Ξc(2939)0)=0011.0±1.9±7.5MeV, m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV}, where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt Λc+K\Lambda_{c}^{+} K^{-} sample. Evidence of a new Ξc(2880)0\Xi_{c}(2880)^{0} state is found with a local significance of 3.8σ3.8\,\sigma, whose mass and width are measured to be 2881.8±3.1±8.5MeV2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV} and 12.4±5.3±5.8MeV12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}, respectively. In addition, evidence of a new decay mode Ξc(2790)0Λc+K\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-} is found with a significance of 3.7σ3.7\,\sigma. The relative branching fraction of BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} with respect to the BD+DKB^{-} \to D^{+} D^{-} K^{-} decay is measured to be 2.36±0.11±0.22±0.252.36 \pm 0.11 \pm 0.22 \pm 0.25, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

    Measurement of the ratios of branching fractions R(D)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

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    The ratios of branching fractions R(D)B(BˉDτνˉτ)/B(BˉDμνˉμ)\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu}) and R(D0)B(BD0τνˉτ)/B(BD0μνˉμ)\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu}) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb1{ }^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τμντνˉμ\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}. The measured values are R(D)=0.281±0.018±0.024\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024 and R(D0)=0.441±0.060±0.066\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is ρ=0.43\rho=-0.43. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Cultivo de tambaqui em canais de abastecimento sob diferentes densidades de peixes

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    A piscicultura moderna baseia-se no melhor sistema de criação, qualidade ambiental e ganhos de produtividade. Neste experimento foi analisado o efeito da densidade de cultivo na qualidade da água, e posteriormente, no desempenho zootécnico dos tambaquis (Colossoma macropomum). Os juvenis de tambaqui com 13,6 ± 4,1g de peso médio foram mantidos em canais de abastecimento com 40 metros de extensão, dividido em quinze seções de um metro cúbico. Foram testadas três densidades (60, 90 e 120 peixe m-³) em delineamento experimental inteiramente casualizado, com cinco repetições. Os resultados dos parâmetros físico-químicos da água foram: temperatura variou de 28,0-31,7 °C, o oxigênio dissolvido de 5,9-7,4 mg L-1, o pH de 6,8-7,5, a concentração média de amônia ficou ao redor de 0,1-0,3 mg L-1. Os valores de alcalinidade e dureza foram de 24,0-34,0 mg L-1 (CaCO3) e 24,0-37,0 mg L-1 (CaCO3, MgCO3). A condutividade elétrica variou entre 0,07-106 µS cm-1 e a concentração do total de sólidos dissolvidos ficou entre 18,37-53,00 mg L-1. Já o ganho de peso final foi de 35,76, 32,95 e 36,25 g para as densidades de 60, 90 e 120 peixes m-3, respectivamente, não sendo verificadas diferenças significativas nos tratamentos avaliados. Os dados do presente estudo abrem precedentes para que cultivo de peixes em canais de irrigação possa ser integrado com outras culturas, maximizando o uso da água

    Neotropical freshwater fisheries : A dataset of occurrence and abundance of freshwater fishes in the Neotropics

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    The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications

    Transverse polarisation measurement of Λ\Lambda hyperons in ppNe collisions at sNN\sqrt{s_{NN}}=68.4 GeV with the LHCb detector

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    A measurement of the transverse polarization of the Λ\Lambda and Λˉ\bar{\Lambda}hyperons in ppNe fixed-target collisions at sNN\sqrt{s_{NN}}=68.4 GeV is presented using data collected by the LHCb detector. The polarization is studied using the decay Λpπ\Lambda \rightarrow p \pi^- together with its charge conjugated process, the integrated values measured are PΛ=0.029±0.019(stat)±0.012(syst), P_{\Lambda} = 0.029 \pm 0.019 \, (\rm{stat}) \pm 0.012 \, (\rm{syst}) \, , PΛˉ=0.003±0.023(stat)±0.014(syst) P_{\bar{\Lambda}} = 0.003 \pm 0.023 \, (\rm{stat}) \pm 0.014 \,(\rm{syst}) \, Furthermore, the results are shown as a function of the Feynman xx variable, transverse momentum, pseudorapidity and rapidity of the hyperons, and are compared with previous measurements.A measurement of the transverse polarization of the Λ\Lambda and Λˉ\bar{\Lambda} hyperons in ppNe fixed-target collisions at sNN\sqrt{s_{NN}} = 68.4 GeV is presented using data collected by the LHCb detector. The polarization is studied using the decay Λpπ\Lambda \rightarrow p \pi^- together with its charge conjugated process, the integrated values measured are PΛ=0.029±0.019(stat)±0.012(syst), P_{\Lambda} = 0.029 \pm 0.019 \, (\rm{stat}) \pm 0.012 \, (\rm{syst}) \, , PΛˉ=0.003±0.023(stat)±0.014(syst). P_{\bar{\Lambda}} = 0.003 \pm 0.023 \, (\rm{stat}) \pm 0.014 \,(\rm{syst}) \,. Furthermore, the results are shown as a function of the Feynman~xx~variable, transverse momentum, pseudorapidity and rapidity of the hyperons, and are compared with previous measurements

    Comprehensive analysis of local and nonlocal amplitudes in the B0K0μ+μB^0 \to K^{*0} \mu^+\mu^- decay

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    A comprehensive study of the local and nonlocal amplitudes contributing to the decay B0K0(K+π)μ+μB^0\rightarrow K^{*0}(\to K^+\pi^-) \mu^+\mu^- is performed by analysing the phase-space distribution of the decay products. The analysis is based on pppp collision data corresponding to an integrated luminosity of 8.4fb1^{-1} collected by the LHCb experiment. This measurement employs for the first time a model of both one-particle and two-particle nonlocal amplitudes, and utilises the complete dimuon mass spectrum without any veto regions around the narrow charmonium resonances. In this way it is possible to explicitly isolate the local and nonlocal contributions and capture the interference between them. The results show that interference with nonlocal contributions, although larger than predicted, only has a minor impact on the Wilson Coefficients determined from the fit to the data. For the local contributions, the Wilson Coefficient C9C_9, responsible for vector dimuon currents, exhibits a 2.1σ2.1\sigma deviation from the Standard Model expectation. The Wilson Coefficients C10C_{10}, C9C_{9}' and C10C_{10}' are all in better agreement than C9C_{9} with the Standard Model and the global significance is at the level of 1.5σ1.5\sigma. The model used also accounts for nonlocal contributions from B0K0[τ+τμ+μ]B^{0}\to K^{*0}\left[\tau^+\tau^-\to \mu^+\mu^-\right] rescattering, resulting in the first direct measurement of the bsττb s\tau\tau vector effective-coupling C9τC_{9\tau}.A comprehensive study of the local and nonlocal amplitudes contributing to the decay B0K0(K+π)μ+μB^0\rightarrow K^{*0}(\to K^+\pi^-) \mu^+\mu^- is performed by analysing the phase-space distribution of the decay products. The analysis is based on \proton\proton collision data corresponding to an integrated luminosity of 8.4fb1^{-1} collected by the LHCb experiment. This measurement employs for the first time a model of both one-particle and two-particle nonlocal amplitudes, and utilises the complete dimuon mass spectrum without any veto regions around the narrow charmonium resonances. In this way it is possible to explicitly isolate the local and nonlocal contributions and capture the interference between them. The results show that interference with nonlocal contributions, although larger than predicted, only has a minor impact on the Wilson Coefficients determined from the fit to the data. For the local contributions, the Wilson Coefficient C9C_9, responsible for vector dimuon currents, exhibits a 2.1σ2.1\sigma deviation from the Standard Model expectation. The Wilson Coefficients C10C_{10}, C9C_{9}' and C10C_{10}' are all in better agreement than C9C_{9} with the Standard Model and the global significance is at the level of 1.5σ1.5\sigma. The model used also accounts for nonlocal contributions from B0K0[τ+τμ+μ]B^{0}\to K^{*0}\left[\tau^+\tau^-\to \mu^+\mu^-\right] rescattering, resulting in the first direct measurement of the bsττb s\tau\tau vector effective-coupling C9τC_{9\tau}

    Study of bb-hadron decays to Λc+hh\Lambda_c^+h^-h^{\prime -} final states

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    Decays of Ξb\Xi_{b}^{-} and Ωb\Omega_{b}^{-} baryons to Λc+hh\Lambda_{c}^{+} h^- h^{\prime -} final states, with hhh^- h^{\prime -} being ππ\pi^{-}\pi^{-}, KπK^{-}\pi^{-} and KKK^{-}K^{-} meson pairs, are searched for using data collected with the LHCb detector. The data sample studied corresponds to an integrated luminosity of 8.7fb18.7 \rm fb^{-1} of pppp collisions collected at centre-of-mass energies s=7\sqrt{s} = 7, 88 and 13TeV13 \rm TeV. The products of the relative branching fractions and fragmentation fractions for each signal mode, relative to the BΛc+pˉπB^{-} \rightarrow \Lambda_{c}^{+} \bar{p} \pi^{-} mode, are measured, with ΞbΛc+Kπ\Xi_{b}^{-} \rightarrow\Lambda_{c}^{+} K^{-} \pi^{-}, ΞbΛc+KK\Xi_{b}^{-} \rightarrow\Lambda_{c}^{+} K^{-} K^{-} and ΩbΛc+KK\Omega_{b}^{-} \rightarrow\Lambda_{c}^{+} K^{-} K^{-} decays being observed at over 5σ5\,\sigma significance. The ΞbΛc+Kπ\Xi_{b}^{-} \rightarrow\Lambda_{c}^{+} K^{-} \pi^{-} mode is also used to measure the Ξb\Xi_{b}^{-} production asymmetry, which is found to be consistent with zero. In addition, the BΛc+pˉKB^{-} \rightarrow \Lambda_{c}^{+} \bar{p} K^{-} decay is observed for the first time, and its branching fraction is measured relative to that of the BΛc+pˉπB^{-} \rightarrow \Lambda_{c}^{+} \bar{p} \pi^{-} mode.Decays of Ξb\Xi_b^- and Ωb\Omega_b^- baryons to Λc+hh\Lambda_c^+ h^- h^{\prime -} final states, with hhh^- h^{\prime -} being ππ\pi^-\pi^-, KπK^-\pi^- and KKK^-K^- meson pairs, are searched for using data collected with the LHCb detector. The data sample studied corresponds to an integrated luminosity of 8.7fb18.7\,\mathrm{fb}^{-1} of pppp collisions collected at centre-of-mass energies s=7\sqrt{s} = 7, 88 and 13TeV13\,\mathrm{Te\kern -0.1em V}. The products of the relative branching fractions and fragmentation fractions for each signal mode, relative to the BΛc+pπB^- \to \Lambda_c^+ \overline{p} \pi^- mode, are measured, with ΞbΛc+Kπ\Xi_{b}^- \to\Lambda_{c}^+ K^- \pi^-, ΞbΛc+KK\Xi_{b}^- \to\Lambda_{c}^+ K^- K^- and ΩbΛc+KK\Omega_{b}^- \to\Lambda_{c}^+ K^- K^- decays being observed at over 5σ5\,\sigma significance. The ΞbΛc+Kπ\Xi_{b}^- \to\Lambda_{c}^+ K^- \pi^- mode is also used to measure the Ξb\Xi_{b}^- production asymmetry, which is found to be consistent with zero. In addition, the BΛc+pKB^- \to \Lambda_{c}^+ \overline{p} K^- decay is observed for the first time, and its branching fraction is measured relative to that of the BΛc+pπB^- \to \Lambda_{c}^+ \overline{p} \pi^- mode
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