Observational constraints on decaying vacuum dark energy model
  The decaying vacuum model (DV), treating dark energy as a varying vacuum, has
been studied well recently. The vacuum energy decays linearly with the Hubble
parameter in the late-times, $\rho_\Lambda(t) \propto H(t)$, and produces the
additional matter component. We constrain the parameters of the DV model using
the recent data-sets from supernovae, gamma-ray bursts, baryon acoustic
oscillations, CMB, the Hubble rate and x-rays in galaxy clusters. It is found
that the best fit of matter density contrast $\Omega_m$ in the DV model is much
lager than that in $\Lambda$CDM model. We give the confidence contours in the
$\Omega_m-h$ plane up to $3\sigma$ confidence level. Besides, the normalized
likelihoods of $\Omega_m$ and $h$ are presented, respectively. %
