  Exploiting the theoretical potential of the modified Bonora-Tonin superfield
approach (MBTSA) as well as the (anti-)chiral superfield approach (ACSA) to
Becchi-Rouet-Stora-Tyutin (BRST) formalism, we derive the complete set of
off-shell nilpotent (anti-)BRST symmetry transformations corresponding to the
classical two $(1 + 1)$-dimensional (2D) diffeomorphism symmetry
transformations on the world-sheet (that is traced out by the motion of a model
of bosonic string). Only the BRST symmetry transformations for this model have
been discussed in the earlier literature. We derive the (anti-)BRST invariant
Curci-Ferrari (CF) type restrictions (using MBTSA) which turn out to be the
root-cause behind the absolute anticommutativity of the above (anti-)BRST
symmetry transformations. We capture the symmetry invariance of the (anti-)BRST
invariant Lagrangian densities within the ambit of ACSA. The derivation of the
proper anti-BRST transformations (corresponding to the already known BRST
transformations) and the (anti-)BRST invariant CF-type restrictions are the
novel results in our present endeavor.

High Energy Physics - Theory