DPF 2011

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)

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

Speaker

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

Description

The ${\mathrm{\Lambda }}_b(udb)$ baryon is observed in the decay ${\mathrm{\Lambda }}_b\to J/\psi \mathrm{\Lambda }$ using 6.1 fb${}^{-1}$ of $p\overline{p}$ 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 $B^0\to J/\psi K_s^0$ is measured to be $0.345\pm 0.034\text{ (stat.)}\pm 0.033\text{ (syst.)}\pm 0.003\text{ (PDG)}$. Using the world average value of $f(b\to B^0)\cdot \mathcal{B}(B^0\to J/\psi K_s^0)=(1.74\pm 0.08)\times {10}^{-5}$, we obtain $f(b\to {\mathrm{\Lambda }}_b)\cdot \mathcal{B}({\mathrm{\Lambda }}_b\to J/\psi \mathrm{\Lambda })=(6.01\pm 0.60\text{ (stat.)}\pm 0.58\text{ (syst.)}\pm 0.28\text{ (PDG)})\times {10}^{-5}$. This measurement represents an improvement in precision by about a factor of three with respect to the current world average.

Presentation materials

Slides

LbBrDPF2011.pdf