  We propose a new mean-field-type framework which can treat the strong
correlation induced by the tensor force. To treat the tensor correlation we
break the charge and parity symmetries of a single-particle state and restore
these symmetries of the total system by the projection method. We perform the
charge and parity projections before variation and obtain a Hartree-Fock-like
equation, which is solved self-consistently. We apply the Hartree-Fock-like
equation to the alpha particle and find that by breaking the parity and charge
symmetries, the correlation induced by the tensor force is obtained in the
projected mean-field framework. We emphasize that the projection before the
variation is important to pick up the tensor correlation in the present
framework.
