Observaciones del rascón pinto, Pardirallus maculatus (Aves: Rallidae) en el centro-occidente de Veracruz

Presentamos los primeros registros del rascón pinto (Pardirallus maculatus) en el centro-oeste de Veracruz, su presencia en esta área puede explicarse por la gran capacidad de dispersión o vagabundeo de la especie o bien, por sesgos en el conocimiento de su distribución. Asimismo, reportamos el consumo de lenteja de agua (Lemnaceae) para este rascón.We report the first records of the Spotted Rail (Pardirallus maculatus) in central-western Veracruz. The presence of Spotted rails in this area can be explained by the high dispersal capabilities or wandering behavior of the species but also it could be due to the fact that there are biases in the knowledge of its distribution. Also, we report the consumption of duckweed plants (Lemnaceae) for this rail

Análisis de la matriz energética de Guatemala, y el comportamiento del precio de los combustibles en función de los precios internacionales.

Desde el inicio del siglo XXI hasta la actualidad, la matriz energética en Guatemala ha variado en precio, capacidad instalada, diversidad de fuentes de generación, tecnología en la transmisión de potencia, y otros factores. Desde el año 1996 cuando se abrió el mercado energético al capital privado, se amplió la variedad de plantas generadoras en el país. En esta situación se hizo necesario analizar variables del sistema como crecimiento anual de la demanda de energía eléctrica, variaciones de los precios del petróleo y sus derivados. Esto con la intención de poder tomar mejores decisiones a la hora de diseñar un plan de expansión del sistema eléctrico para el futuro crecimiento del país. En base a estos datos se pueden encontrar, por medio de métodos estocásticos, relaciones entre los precios de los derivados del petróleo con el precio del petróleo mismo que permiten entender mejor como impactan en la vida cotidiana de los guatemaltecos y guatemaltecas

El Cañón del Río Blanco National Park: A Forgotten Protected Natural Area

Objective: Present the current situation of the Cañón del Río Blanco National Park and gathering in a single document all the existing information of this Protected Natural Area (PNA). Design/methodology/approach: Both a bibliographic research and field work were carried out to determine the current state of the PNA. Results: The decree, the geographical location, history of its protection, biological, sociocultural and economic characteristics, environmental services, CONANP work program, environmental problems and category issues are described. Limitations on study/implications: There were no limitations. Findings/conclusions: The area still protects an important biodiversity, also fulfilling vital environmental services, but it is urgent to assign it an adequate category, as well as a director of the park.Objective: To submit a report about the current situation of the Cañón del Río Blanco National Park and to gather all the existing information about this Protected Natural Area (PNA) in a single document. Design/Methodology/Approach: A bibliographic research and field work were carried out to determine the current state of the PNA. Results: The decree, the geographical location, the history of its protection, the biological, sociocultural and economic characteristics, the environmental services, the CONANP work program, the environmental problems, and the category issues are described. Study Limitations/Implications: There were no limitations. Findings/Conclusions: The area still protects an important biodiversity and fulfills vital environmental services; however, assigning an adequate category to the park and appointing a director is an urgent matter

Tracking of charged particles with nanosecond lifetimes at LHCb

A method is presented to reconstruct charged particles with lifetimes between 10 ps and 10 ns, which considers a combination of their decay products and the partial tracks created by the initial charged particle. Using the $\Xi^-$ baryon as a benchmark, the method is demonstrated with simulated events and proton-proton collision data at $\sqrt{s}=13$ TeV, corresponding to an integrated luminosity of 2.0 fb${}^{-1}$ collected with the LHCb detector in 2018. Significant improvements in the angular resolution and the signal purity are obtained. The method is implemented as part of the LHCb Run 3 event trigger in a set of requirements to select detached hyperons. This is the first demonstration of the applicability of this approach at the LHC, and the first to show its scaling with instantaneous luminosity

Study of Bc+→χcπ+B_c^+ \rightarrow \chi_c \pi^+ decays

International audienceA study of $B_c^+ \rightarrow \chi_c \pi^+$ decays is reported using proton-proton collision data, collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9fb$^{-1}$. The decay $B_c^+ \rightarrow \chi_{c2} \pi^+$ is observed for the first time, with a significance exceeding seven standard deviations. The relative branching fraction with respect to the $B_c^+ \rightarrow J/\psi \pi^+$ decay is measured to be $$\frac{\mathcal{B}_{B_c^+ \rightarrow \chi_{c2} \pi^+}} {\mathcal{B}_{B_c^+ \rightarrow J/\psi \pi^+}} = 0.37 \pm 0.06 \pm 0.02 \pm 0.01 ,$$ where the first uncertainty is statistical, the second is systematic, and the third is due to the knowledge of the $\chi_c \rightarrow J/\psi \gamma$ branching fraction. No significant $B_c^+ \rightarrow \chi_{c1} \pi^+$ signal is observed and an upper limit for the relative branching fraction for the $B_c^+ \rightarrow \chi_{c1} \pi^+$ and $B_c^+ \rightarrow \chi_{c2} \pi^+$ decays of $$\frac{\mathcal{B}_{B_c^+ \rightarrow \chi_{c1} \pi^+}} {\mathcal{B}_{B_c^+ \rightarrow \chi_{c2} \pi^+}} < 0.49$$ is set at the 90% confidence level

Search for the Bs0→μ+μ−γB_s^0 \rightarrow \mu^+\mu^-\gamma decay

International audienceA search for the fully reconstructed $B_s^0 \rightarrow \mu^+\mu^-\gamma$ decay is performed at the LHCb experiment using proton-proton collisions at $\sqrt{s}=13$ TeV corresponding to an integrated luminosity of $5.4\,\mathrm{fb^{-1}}$. No significant signal is found and upper limits on the branching fraction in intervals of the dimuon mass are set \begin{align} {\cal B}(B_s^0 \rightarrow \mu^+\mu^-\gamma) < 4.2\times10^{-8},~&m(\mu\mu)\in[2m_\mu,~1.70]\,\mathrm{GeV/c^2} ,\nonumber {\cal B}(B_s^0 \rightarrow \mu^+\mu^-\gamma) < 7.7\times10^{-8},~&m(\mu\mu)\in[1.70,~2.88]\,\mathrm{GeV/c^2},\nonumber {\cal B}(B_s^0 \rightarrow \mu^+\mu^-\gamma) < 4.2\times10^{-8},~&m(\mu\mu)\in[3.92 ,~m_{B_s^0}]\,\mathrm{GeV/c^2},\nonumber \end{align} at 95% confidence level. Additionally, upper limits are set on the branching fraction in the $[2m_\mu,~1.70]\,\mathrm{GeV/c^2}$ dimuon mass region excluding the contribution from the intermediate $\phi(1020)$ meson, and in the region combining all dimuon-mass intervals

First observation of Λb0→Σc(∗)++D(∗)−K−\Lambda_{b}^{0} \rightarrow \Sigma_c^{(*)++} D^{(*)-} K^{-} decays

International audienceThe four decays, $\Lambda_{b}^{0} \rightarrow \Sigma_c^{(*)++} D^{(*)-} K^{-}$, are observed for the first time using proton-proton collision data collected with the LHCb detector at a centre-of-mass energy of $13\,\rm{TeV}$, corresponding to an integrated luminosity of $6\,\rm{fb}^{-1}$. By considering the $\Lambda_b^0 \rightarrow \Lambda_c^{+} \overline{D}^0 K^{-}$ decay as reference channel, the following branching fraction ratios are measured to be, $$\frac{\cal{B} (\Lambda_{b}^{0} \rightarrow \Sigma_{c}^{++} \rm{D}^{-} {K}^{-})}{\cal{B}(\Lambda_{b}^{0} \rightarrow \Lambda_c^{+} \rm \overline{D}^0 {K}^{-})} = {0.282}\pm{0.016}\pm{0.016}\pm{0.005}, \frac{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_{c}^{*++} \rm {D}^{-} {K}^{-})}{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_c^{++} \rm {D}^{-} {K}^{-})} = {0.460}\pm{0.052}\pm{0.028}, \frac{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_{c}^{++} \rm {D}^{*-} {K}^{-})}{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_c^{++} \rm {D}^{-} {K}^{-})} = {2.261}\pm{0.202}\pm{0.129}\pm{0.046}, \frac{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_{c}^{*++} \rm D^{*-} K^{-})}{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_c^{++} \rm D^{-} K^{-})} = {0.896}\pm{0.137}\pm{0.066}\pm{0.018},$$ where the first uncertainties are statistical, the second are systematic, and the third are due to uncertainties in the branching fractions of intermediate particle decays. These initial observations mark the beginning of pentaquark searches in these modes, with more data set to become available following the LHCb upgrade