  The anisotropic two-orbital Hubbard model is investigated at low temperatures
using high-precision quantum Monte Carlo (QMC) simulations within dynamical
mean-field theory (DMFT). We demonstrate that two distinct orbital-selective
Mott transitions (OSMTs) occur for a bandwidth ratio of 2 even without
spin-flip contributions to the Hund exchange, and we quantify numerical errors
in earlier QMC data which had obscured the second transition. The limit of
small inter-orbital coupling is introduced via a new generalized Hamiltonian
and studied using QMC and Potthoff's self-energy functional method, yielding
insight into the nature of the OSMTs and the non-Fermi-liquid OSM phase and
opening the possibility for a new quantum-critical point.
