  Using a proton-proton collision data sample collected by the LHCb experiment,
corresponding to an integrated luminosity of 8.5 fb$^{-1}$, the observation of
a new excited $\Xi_b^0$ resonance decaying to the $\Xi_b^-\pi^+$ final state is
presented. The state, referred to as $\Xi_b(6227)^0$, has a measured mass and
natural width of
  $m(\Xi_b(6227)^0) = 6227.1^{\,+1.4}_{\,-1.5}\pm0.5$ MeV,
  $\Gamma(\Xi_b(6227)^0) = 18.6^{\,+5.0}_{\,-4.1}\pm1.4$ MeV, where the
uncertainties are statistical and systematic. The production rate of the
$\Xi_b(6227)^0$ state relative to that of the $\Xi_b^-$ baryon in the kinematic
region $2<\eta<5$ and $p_{\rm T}<30$ GeV is measured to be
  $\frac{f_{\Xi_b(6227)^0}}{f_{\Xi_b^-}}{\mathcal{B}}(\Xi_b(6227)^0\to\Xi_b^-\pi^+)
= 0.045\pm0.008\pm0.004$, where ${\mathcal{B}}(\Xi_b(6227)^0\to\Xi_b^-\pi^+)$
is the branching fraction of the decay, and $f_{\Xi_b(6227)^0}$ and
$f_{\Xi_b^-}$ represent fragmentation fractions.
  Improved measurements of the mass and natural width of the previously
observed $\Xi_b(6227)^-$ state, along with the mass of the $\Xi_b^-$ baryon,
are also reported. Both measurements are significantly more precise than, and
consistent with, previously reported values.
