Observation and Mass Measurement of the Baryon ${\Xi }_b^{-}$

T. Aaltonen

We report the observation and measurement of the mass of the bottom, strange baryon ${\Xi }_b^{-}$ through the decay chain ${\Xi }_b^{-}\to J/\psi {\Xi }^{-}$, where $J/\psi \to {\mu }^{+}{\mu }^{-}$, ${\Xi }^{-}\to \Lambda {\pi }^{-}$, and…