616 research outputs found

    Study of the B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

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    The decay B−→Λc+Λˉc−K−B^{-} \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 fb−1\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±1.1 MeV,m(Ξc(2939)0)=2938.5±0.9±2.3 MeV,Γ(Ξc(2923)0)=0004.8±0.9±1.5 MeV,Γ(Ξc(2939)0)=0011.0±1.9±7.5 MeV, 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 3.8 σ3.8\,\sigma, whose mass and width are measured to be 2881.8±3.1±8.5 MeV2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV} and 12.4±5.3±5.8 MeV12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}, respectively. In addition, evidence of a new decay mode Ξc(2790)0→Λc+K−\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-} is found with a significance of 3.7 σ3.7\,\sigma. The relative branching fraction of B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} with respect to the B−→D+D−K−B^{-} \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(Bˉ→D∗τ−Μˉτ)/B(Bˉ→D∗Ό−ΜˉΌ)\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(B−→D0τ−Μˉτ)/B(B−→D0Ό−ΜˉΌ)\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 fb−1{ }^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τ−→Ό−ΜτΜˉΌ\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

    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 fb−1^{-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

    Compromiso hepåtico por dengue en niños del huila, colombia

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    Objetivo Determinar la frecuencia y severidad del compromiso hepĂĄtico en niños con Dengue.MĂ©todos Estudio descriptivo que incluyĂł a 108 niños menores de 13 años con diagnĂłstico de infecciĂłn por virus de Dengue, confirmada por detecciĂłn plasmĂĄtica de NS1 e IgM dengue-especĂ­fica, que consultaron al Hospital Universitario de Neiva, en el perĂ­odo de junio de 2009 a mayo de 2010.El grado de daño hepĂĄtico fue evaluado por criterios clĂ­nicos y bioquĂ­micos que incluyeron transaminasas y albĂșmina. El diagnĂłstico de infecciĂłn con Leptospira o Hepatitis A fue realizado por detecciĂłn de IgM plasmĂĄtica especĂ­fica medida en fase aguda y convaleciente.Resultados De los casos incluidos, 98 y 10 casos fueron clasificados como dengue con signos de alarma y Dengue grave, respectivamente. Dos de cada tres pacientes con Dengue presentaron signos de alarma y todos los pacientes con Dengue grave presentaron algĂșn grado de compromiso hapĂĄtico evidenciado clĂ­nica y bioquĂ­micamente. Independientemente de la clasificaciĂłn clĂ­nica, la hepatomegalia fue el signo clĂ­nico cardinal del compromiso hepĂĄtico y se presentĂł en el 85 % del total de niños incluidos. De resaltar, 5 de los pacientes presentaron probable coinfecciĂłn de dengue y leptospira, siendo la primera descripciĂłn en Colombia. En ninguno de los casos analizados se presentĂł enfermedad aguda por Hepatitis A.ConclusiĂłn El compromiso hepĂĄtico es muy frecuente en la infecciĂłn por virus Dengue. Enfermedades como la leptospirosis deben ser tenidas en cuenta no sĂłlo en el diagnĂłstico diferencial del paciente pediĂĄtrico febril con compromiso hepĂĄtico, sino como causa de coinfecciĂłn en el niño con Dengue en el sur de Colombia

    Spatio-temporal dynamics of Plasmodium falciparum transmission within a spatial unit on the Colombian Pacific Coast.

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    As malaria control programmes concentrate their efforts towards malaria elimination a better understanding of malaria transmission patterns at fine spatial resolution units becomes necessary. Defining spatial units that consider transmission heterogeneity, human movement and migration will help to set up achievable malaria elimination milestones and guide the creation of efficient operational administrative control units. Using a combination of genetic and epidemiological data we defined a malaria transmission unit as the area contributing 95% of malaria cases diagnosed at the catchment facility located in the town of Guapi in the South Pacific Coast of Colombia. We provide data showing that P. falciparum malaria transmission is heterogeneous in time and space and analysed, using topological data analysis, the spatial connectivity, at the micro epidemiological level, between parasite populations circulating within the unit. To illustrate the necessity to evaluate the efficacy of malaria control measures within the transmission unit in order to increase the efficiency of the malaria control effort, we provide information on the size of the asymptomatic reservoir, the nature of parasite genotypes associated with drug resistance as well as the frequency of the Pfhrp2/3 deletion associated with false negatives when using Rapid Diagnostic Tests

    XV International Congress of Control Electronics and Telecommunications: "The role of technology in times of pandemic and post-pandemic: innovation and development for strategic social and productive sectors"

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    La anterior selecciĂłn, motivados por la aseveraciĂłn de Manuel Castells -hace casi 20 años ya- que la innovaciĂłn y la difusiĂłn de la tecnologĂ­a parecĂ­a ser la herramienta apropiada para el desarrollo en la era de la informaciĂłn. Este 2020, sin embargo, ante la situaciĂłn disruptiva que aquejĂł y aqueja a la sociedad red como una estructura social emergente de la Era de la InformaciĂłn basada en redes de producciĂłn, energizadas por el poder y la experiencia; fallĂł y debe reencontrar su rumbo. Es asĂ­ que los problemas acuciantes, ahora, fueron: la atenciĂłn sanitaria y la superaciĂłn de la epidemia de Sars Cov 2; tomĂł forma la, hasta entonces, visiĂłn irrealista de Castells que 
 no podemos avanzar con nuestros modelos de desarrollo actual, destruyendo nuestro entorno y excluyendo a la mayor parte de la humanidad de los beneficios de la revoluciĂłn tecnolĂłgica mĂĄs extraordinaria de la historia, sin sufrir una devastadora reacciĂłn por parte de la sociedad y la naturaleza. Fue asĂ­ que el Cuarto Mundo, especĂ­ficamente, donde la suficiencia de recurso humano, de capital, trabajo, informaciĂłn y mercado -vinculados todos a travĂ©s de la tecnologĂ­a- supuso que atenderĂ­a eficazmente a travĂ©s de la poblaciĂłn que podĂ­a por su capacidad hacer uso racional y profesional del conocimiento, las necesidades de la mayoritaria poblaciĂłn vulnerable y vulnerada. Por lo anterior, poner en el centro a las personas, en entornos de tarea y trabajo globales hiperconectados combinando espacios fĂ­sicos, corrientes de informaciĂłn con canales de conexiĂłn expeditos, y formando profesionales del conocimiento que asuman y afronten los retos derivados de la transformaciĂłn digital de empresas, universidades, y organizaciones, pero en condiciones de equidad y sujetos de prosperidad, serĂĄ el desafĂ­o en los escenarios presentes y futuros inmediatos.The previous selection, motivated by the assertion of Manuel Castells -almost 20 years ago- that innovation and diffusion of technology seemed to be the appropriate tool for development in the information age. This 2020, however, in the face of the disruptive situation that afflicted and continues to afflict the network society as an emerging social structure of the Information Age based on production networks, energized by power and experience; He failed and must find his way again. Thus, the pressing problems now were: health care and overcoming the Sars Cov 2 epidemic; Castells' until then unrealistic vision took shape that... we cannot advance with our current development models, destroying our environment and excluding the majority of humanity from the benefits of the most extraordinary technological revolution in history, without suffering a devastating reaction from society and nature. It was thus that the Fourth World, specifically, where the sufficiency of human resources, capital, work, information and market - all linked through technology - meant that it would serve effectively through the population that could, due to its capacity, make rational use. and knowledge professional, the needs of the majority vulnerable and vulnerable population. Therefore, putting people at the center, in hyperconnected global task and work environments, combining physical spaces, information flows with expedited connection channels, and training knowledge professionals who assume and face the challenges derived from the digital transformation of companies, universities, and organizations, but in conditions of equality and subject to prosperity, will be the challenge in the present and immediate future scenarios.Bogot

    Improved measurement of CPCP violation parameters in Bs0→J/ψK+K−B_s^0\to J/\psi K^+K^- decays in the vicinity of the ϕ(1020)\phi(1020) resonance

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    The decay-time-dependent CPCP asymmetry in Bs0→J/ψ(→Ό+Ό−)K+K−B_s^0\to J/\psi(\to \mu^+\mu^-) K^+ K^- decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 6fb−16 {\rm fb}^{-1}, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 Bs0B_s^0 signal decays with an invariant K+K−K^+ K^- mass in the vicinity of the ϕ(1020)\phi(1020) resonance, the CPCP-violating phase ϕs\phi_s is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the Bs0B_s^0-B‟s0\overline{B}_s^0 system, ΔΓs\Delta\Gamma_s, and the difference of the average Bs0B_s^0 and B0B^0 meson decay widths, Γs−Γd\Gamma_s-\Gamma_d. The values obtained are ϕs=−0.039±0.022±0.006\phi_s = -0.039 \pm 0.022 \pm 0.006 rad, ΔΓs=0.0845±0.0044±0.0024 ps−1\Delta\Gamma_s = 0.0845 \pm 0.0044 \pm 0.0024 ~{\rm ps}^{-1} and Γs−Γd=−0.056 − 0.0015 + 0.0013±0.0014 ps−1\Gamma_s-\Gamma_d = -0.056^{\:+\:0.0013}_{\:-\:0.0015} \pm 0.0014 ~{\rm ps}^{-1}, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements to date and are consistent with expectations based on the Standard Model and with the previous LHCb analyses of this decay. These results are combined with previous independent LHCb measurements. The phase ϕs\phi_s is also measured independently for each polarization state of the K+K−K^+K^- system and shows no evidence for polarization dependence.The decay-time-dependent CPCP asymmetry in Bs0→J/ψ(→Ό+Ό−)K+K−B^0_s\to J/\psi(\to \mu^{+}\mu^{-}) K^{+}K^{-} decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 6 fb−1fb^{-1}, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 Bs0B^{0}_{s} signal decays with an invariant K+K−K^{+}K^{-} mass in the vicinity of the ϕ(1020)\phi(1020) resonance, the CPCP-violating phase ϕs\phi_s is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the Bs0B^0_s-Bˉs0\bar{B}^0_s system, ΔΓs\Delta\Gamma_s, and the difference of the average Bs0B^0_s and B0B^0 meson decay widths, Γs−Γd\Gamma_s-\Gamma_d. The values obtained are ϕs= −0.039±0.022±0.006\phi_s = \ -0.039 \pm 0.022 \pm 0.006 rad, ΔΓs=0.0845±0.0044±0.0024\Delta\Gamma_s = 0.0845 \pm 0.0044 \pm 0.0024 ps−1^{-1} and Γs−Γd=−0.0056−0.0015+0.0013±0.0014\Gamma_s-\Gamma_d = -0.0056 ^{+ 0.0013}_{-0.0015} \pm 0.0014 ps−1^{-1}, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements to date and are consistent with expectations based on the Standard Model and with the previous LHCb analyses of this decay. These results are combined with previous independent LHCb measurements. The phase ϕs\phi_s is also measured independently for each polarization state of the K+K−K^{+}K^{-} system and shows no evidence for polarization dependence

    Measurement of CP violation in B0→ψ(→ℓ+ℓ−)KS0(→π+π−)B^0\to\psi(\to\ell^+\ell^-)K^0_S(\to\pi^+\pi^-) decays

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    International audienceA measurement of time-dependent CP violation in the decays of B0B^0 and B‟0\overline{B}^0 mesons to the final states J/ψ(→Ό+Ό−)KS0J/\psi(\to\mu^+\mu^-)K^0_S, ψ(2S)(→Ό+Ό−)KS0\psi(2S)(\to\mu^+\mu^-)K^0_S and J/ψ(→e+e−)KS0J/\psi(\to e^+e^-)K^0_S with KS0→π+π−K^0_S\to\pi^+\pi^- is presented. The data correspond to an integrated luminosity of 6 fb−1{}^{-1} collected at a centre-of-mass energy of s=13\sqrt{s}=13 TeV with the LHCb detector. The CP-violation parameters are measured to be \begin{align*} S_{\psi K^0_S} &= 0.717 \pm 0.013 (\text{stat}) \pm 0.008 (\text{syst}), \\ C_{\psi K^0_S} &= 0.008 \pm 0.012 (\text{stat}) \pm 0.003 (\text{syst}). \end{align*} This measurement of SψKS0S_{\psi K^0_S} represents the most precise single measurement of the CKM angle ÎČ\beta to date and is more precise than the current world average. In addition, measurements of the CP-violation parameters of the individual channels are reported and a combination with the LHCb Run 1 measurements is performed

    Measurement of CP violation in B0→ψ(→ℓ+ℓ−)KS0(→π+π−)B^0\to\psi(\to\ell^+\ell^-)K^0_S(\to\pi^+\pi^-) decays

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    International audienceA measurement of time-dependent CP violation in the decays of B0B^0 and B‟0\overline{B}^0 mesons to the final states J/ψ(→Ό+Ό−)KS0J/\psi(\to\mu^+\mu^-)K^0_S, ψ(2S)(→Ό+Ό−)KS0\psi(2S)(\to\mu^+\mu^-)K^0_S and J/ψ(→e+e−)KS0J/\psi(\to e^+e^-)K^0_S with KS0→π+π−K^0_S\to\pi^+\pi^- is presented. The data correspond to an integrated luminosity of 6 fb−1{}^{-1} collected at a centre-of-mass energy of s=13\sqrt{s}=13 TeV with the LHCb detector. The CP-violation parameters are measured to be \begin{align*} S_{\psi K^0_S} &= 0.717 \pm 0.013 (\text{stat}) \pm 0.008 (\text{syst}), \\ C_{\psi K^0_S} &= 0.008 \pm 0.012 (\text{stat}) \pm 0.003 (\text{syst}). \end{align*} This measurement of SψKS0S_{\psi K^0_S} represents the most precise single measurement of the CKM angle ÎČ\beta to date and is more precise than the current world average. In addition, measurements of the CP-violation parameters of the individual channels are reported and a combination with the LHCb Run 1 measurements is performed
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