High $p_{t}$ squeezed-out nucleons as a probe of $K_{\rm{sym}}$ of the symmetry energy.

In the framework of the Isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model, the effects of the curvature of nuclear symmetry energy at saturation density on the squeezed-out nucleons are demonstrated in the semi-central Au+Au reaction at 400 MeV/nucleon. It is clearly shown that the squeezed-out isospin-dependent nucleon emissions at high transverse momenta, i.e., the isospin-dependent nucleon elliptic flow and the squeezed-out free neutron to proton ratio at high transverse momenta are both sensitive to the curvature of nuclear symmetry energy at saturation density. The curvature of nuclear symmetry energy at saturation density thus can be directly probed by the high momentum squeezed-out nucleons from dense matter formed in the semi-central heavy-ion collisions.