# DPF 2011

8-13 August 2011
Rhode Island Convention Center
US/Eastern timezone

## Measurement of the production fraction times branching fraction f(b->Lambda_b)xB(Lambda_b -> J/psi Lambda)

12 Aug 2011, 16:00
20m
554 (Rhode Island Convention Center)

### 554

#### Rhode Island Convention Center

Parallel contribution Heavy Flavor Physics (bottom, charm, tau)

### 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.

### Primary author

Ivan Heredia De La Cruz (Centro Invest. Estudios Avanz. IPN (CINVESTAV))

 Slides