  An inclusive search for supersymmetry in events with at least one b-tagged
jet is performed using proton-proton collision data collected by the CMS
experiment in 2012 at a center-of-mass energy of 8 TeV. The data set size
corresponds to an integrated luminosity of 19.3 inverse femtobarns. The
two-dimensional distribution of the razor variables R^2 and M[R] is studied in
events with and without leptons. The data are found to be consistent with the
expected background, which is modeled with an empirical function. Exclusion
limits on supersymmetric particle masses at a 95% confidence level are derived
in several simplified supersymmetric scenarios for several choices of the
branching fractions. By combining the likelihoods of a search in events without
leptons and a search that requires a single lepton (electron or muon), an
improved bound on the top-squark mass is obtained. Assuming the lightest
supersymmetric particle to be stable and weakly interacting, and to have a mass
of 100 GeV, the branching-fraction-dependent (-independent) production of
gluinos is excluded for gluino masses up to 1310 (1175) GeV. The corresponding
limit for top-squark pair production is 730 (645) GeV.
