  In recent years a consensus has gradually been reached that the previously
proposed deconfined quantum critical point (DQCP) for spin-1/2 systems, an
archetypal example of quantum phase transition beyond the classic Landau's
paradigm, actually does not correspond to a true unitary conformal field theory
(CFT). In this work we carefully investigate another type of quantum phase
transition supposedly beyond the similar classic paradigm, the so called
``symmetric mass generation" (SMG) transition proposed in recent years. We
employ the sharp diagnosis including the scaling of disorder operator and
R\'enyi entanglement entropy in large-scale lattice model quantum Monte Carlo
simulations. Our results strongly suggest that the SMG transition is indeed an
unconventional quantum phase transition and it should correspond to a true
$(2+1)d$ unitary CFT.
