Testing an anisotropic spinor field--based Modified Chaplygin Gas model in Kantowski--Sachs spacetime with observational constraints

We investigate a cosmological model based on a massless nonlinear spinor field coupled to a Modified Chaplygin Gas (MCG) in the Kantowski–Sachs spacetime, aiming to probe anisotropies and unified dark sector dynamics. The model parameters are constrained using recent observational data, including Pantheon+, cosmic chronometers, DESI DR2, and CMB distance priors, via a Markov Chain Monte Carlo analysis. We find $H_0\sim 67$–$68\mathrm{k}\mathrm{m}{\mathrm{s}}^{-1}\mathrm{M}\mathrm{p}{\mathrm{c}}^{-1}$, while the shear parameter is consistent with zero, indicating an effectively isotropic Universe at late times. The model reproduces late-time cosmic acceleration with a present-day deceleration parameter $q_0\sim -0.49$, and provides a good fit to the data, yielding a lower minimum ${\chi }^2$ than $\mathrm{\Lambda }$CDM, and is favored by the Akaike Information Criterion. Overall, the spinor field MCG model in Kantowski–Sachs spacetime offers a viable framework that naturally incorporates anisotropy and a unified description of dark matter and dark energy, consistent with current observations.