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arXiv · 0707.0589

Observation and Mass Measurement of the Baryon $Ξ^-_b$

T. Aaltonen
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Abstract

We report the observation and measurement of the mass of the bottom, strange baryon $Ξ^-_b$ through the decay chain $Ξ^-_b \to J/ψΞ^-$, where $J/ψ\to μ^+ μ^-$, $Ξ^- \to Λπ^-$, and $Λ\to p π^-$. Evidence for observation is based on a signal whose probability of arising from the estimated background is 6.6 x 10^{-15}, or 7.7 Gaussian standard deviations. The $Ξ^-_b$ mass is measured to be $5792.9\pm 2.5$ (stat.) $\pm 1.7$ (syst.) MeV/$c^2$.

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T. Aaltonen. 2007-07-30. Observation and Mass Measurement of the Baryon $Ξ^-_b$. https://doi.org/10.1103/physrevlett.99.052002

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