  We consider a Mott transition of the Hubbard model in infinite dimensions.
The dynamical mean- field theory is employed in combination with a
continuous-time quantum Monte Carlo (CTQMC) method for an accurate description
at low temperatures. From the double occupancy and the energy density, which
are directly measured from the CTQMC method, we construct the phase diagram. We
pay particular attention to the construction of the first-order phase
transition line (PTL) in the co- existence region of metallic and insulating
phases. The resulting PTL is found to exhibit reasonable agreement with earlier
finite-temperature results. We also show by a systematic inclusion of low-
temperature data that the PTL, which is achieved independently of the previous
zero-temperature results, approaches monotonically the transition point from
earlier zero-temperature studies.
