Finite Field-dependent Symmetry in Thirring Model

In this paper, we consider a $D$-dimensional massive Thirring model with ($2<D<4$). We derive an extended BRST symmetry of the theory with finite field-dependent parameter. Further we compute the Jacobian of functional measure under such an extended transformation. Remarkably, we find that such Jacobian extends the BRST exact part of the action which leads to a mapping between different gauges. We illustrate this with the help of Lorentz and $R_\xi$ gauges. We also discuss the results in Batalin-Vilkovisky framework.