ICAR: endoscopic skull‐base surgery

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Measurement of the branching fraction of B0 → J/ψπ0 decays

Abstract The ratio of branching fractions between B0 → J/ψπ0 and B+ → J/ψK*+ decays is measured with proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb−1. The measured value is$$\frac{{\mathcal{B}}_{B^0\to J/\psi {\pi}^0}}{{\mathcal{B}}_{B^{+}\to J/\psi {K}^{\ast +}}}=\left(1.153\pm 0.053\pm 0.048\right)\times {10}^{-2},$$ B B 0 → J / ψ π 0 B B + → J / ψ K ∗ + = 1.153 ± 0.053 ± 0.048 × 10 − 2 , where the first uncertainty is statistical and the second is systematic. The branching fraction for B0 → J/ψπ0 decays is determined using the branching fraction of the normalisation channel, resulting in$${\mathcal{B}}_{B^0\to J/\psi {\pi}^0}=\left(1.670\pm 0.077\pm 0.069\pm 0.095\right)\times {10}^{-5},$$ B B 0 → J / ψ π 0 = 1.670 ± 0.077 ± 0.069 ± 0.095 × 10 − 5 , where the last uncertainty corresponds to that of the external input. This result is consistent with the current world average value and competitive with the most precise single measurement to date.</jats:p

Study of Bc+ → χc π+ decays

A study of B-c(+) -&gt; 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 13TeV, corresponding to an integrated luminosity of 9 fb(-1). The decay B-c(+) -&gt; 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(+) -&gt; J/psi pi(+) decay is measured to beBBc+ -&gt;chi c2 pi+/BBc+ -&gt; (J/psi pi+) = 0.37 +/- 0.06 +/- 0.02 +/- 0.01,where the first uncertainty is statistical, the second is systematic, and the third is due to the knowledge of the chi(c2) -&gt; J/psi gamma branching fraction. No significant B-c(+) -&gt; chi(+)(c1 pi) signal is observed and an upper limit for the relative branching fraction for the B-c(+) -&gt; chi(c1)pi(+) and B-c(+) -&gt; chi(c2)pi(+) decays ofBBc+ -&gt;chi c1 pi+/BBc+ -&gt; chi(c2)pi(+) &lt; 0.49is set at the 90% confidence level

Tracking of charged particles with nanosecond lifetimes at LHCb

AbstractA method is presented to reconstruct charged particles with lifetimes between $$10\,\text {ps}$$ 10 ps and $$10\,\text {ns},$$ 10 ns , which considers a combination of their decay products and the partial tracks created by the initial charged particle. Using the $${\varXi } ^-$$ Ξ - baryon as a benchmark, the method is demonstrated with simulated events and proton-proton collision data at $$\sqrt{s} =13\,\text {TeV},$$ s = 13 TeV , corresponding to an integrated luminosity of 2.0$$\,\text {fb} ^{-1}$$ 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.</jats:p