  Using ultrafast broad-band transient absorption (TA) spectroscopy of
photo-excited MAPbBr3 thin films with probe continua in the visible and the
mid-to-deep-UV ranges, we capture the ultrafast gap renormalization at the
fundamental gap situated at the R symmetry point of the Brillouin Zone (BZ) and
a higher energy gap at the M point. Global Lifetime analysis, Lifetime density
distribution and spectral trace fitting analysis are applied to extract
quantitative information. Our work confirms the similarity of the energy gap
renormalization at both symmetry points, which rises within the instrument
response function (IRF, ~250 fs) and decays in ~400-600 fs times, and an energy
red-shift of ~90-150 meV. The ability to monitor different high symmetry points
in photoexcited perovskites opens exciting prospects into the characterization
of materials, which can be extended to a larger class of materials.
