A modified gravity model fitted to supernova data with extra ingredients

A flat FLRW cosmology is built inside F(R,Σ,T) gravity — a theory where the action depends on the Ricci scalar, a matter-coupling term, and the trace of the stress-energy tensor — and then further augmented with gravitationally induced particle creation and a variable generalized Chaplygin gas as dark energy. Free parameters are constrained against the Pantheon+ Type Ia supernova compilation and Hubble data via chi-squared minimisation. The model reproduces accelerated expansion and passes thermodynamic consistency checks at the apparent horizon, but the result is a confirmation that the framework is viable rather than a new prediction or tight observational constraint.