Speaker
Ivan Heredia De La Cruz
(Centro Invest. Estudios Avanz. IPN (CINVESTAV))
Description
The $\Lambda_{b}(udb)$ baryon is observed in the decay $\Lambda_{b}\to J/\psi \Lambda$ using 6.1 fb$^{-1}$ of $p\bar{p}$ collisions collected with the D0 detector at
$\sqrt{s}=1.96$ TeV. The production fraction multiplied by the branching fraction for this decay relative to that for the decay $B^{0}\to J/\psi K^{0}_{s}$ is measured to be $0.345 \pm 0.034 \mbox{ (stat.)} \pm 0.033\mbox{ (syst.)} \pm 0.003\mbox{ (PDG)}$.
Using the world average value of $f(b\to B^{0})\cdot\mathcal{B}(B^{0}\to J/\psi K^{0}_{s})=(1.74\pm 0.08)\times 10^{-5}$, we obtain $f(b\to\Lambda_{b})\cdot \mathcal{B} \left( \Lambda_{b} \rightarrow J/\psi \Lambda \right) = (6.01\pm 0.60\mbox{ (stat.)}\pm0.58\mbox{ (syst.)} \pm 0.28 \mbox{ (PDG)})\times 10^{-5}$. This measurement represents an improvement in precision by about a factor of three with
respect to the current world average.
Author
Ivan Heredia De La Cruz
(Centro Invest. Estudios Avanz. IPN (CINVESTAV))
