  Supersymmetry does not dictate the way we should quantize the fields in the
supermultiplets, and so we have the freedom to quantize the Standard Model (SM)
particles and their superpartners differently. We propose a generalized
quantization scheme under which a particle can only appear off-shell, while its
contributions to quantum corrections are exactly the same as those in the usual
quantum field theory. We apply this quantization scheme solely to the
sparticles in the $R$-parity preserving Minimal Supersymmetric Standard Model
(MSSM). Thus sparticles can only appear off-shell. They could be light but
would completely escape the direct detection at any experiments such as the
LHC. However, our theory still retains the same desirable features of the usual
MSSM at the quantum level. For instance, the gauge hierarchy problem is solved
and the three MSSM gauge couplings are unified in the usual way. Although
direct detection of sparticles is impossible, their existence can be revealed
by precise measurements of some observables (such as the running QCD coupling)
that may receive quantum corrections from them and have sizable deviations from
the SM predictions. Also the experimental constraints from the indirect
sparticle search are still applicable.
