  The presence of a critical point in the QCD phase diagram can deform the
trajectories describing the evolution of the expanding fireball in the
$\mu_B-T$ phase diagram. If the average emission time of hadrons is a function
of transverse velocity, as microscopic simulations of the hadronic freeze-out
dynamics suggest, the deformation of the hydrodynamic trajectories will change
the transverse velocity ($\beta_{\rm T}$) dependence of the proton-antiproton
ratio when the fireball passes in the vicinity of the critical point. An
unusual $\beta_{\rm T}$-dependence of the $\bar{p}/p$ ratio in a narrow beam
energy window would thus signal the presence of the critical point.
