Exploring mutated hilltop inflation in $f(\phi ,T)$ gravity with latest CMB and DESI observations

The high-precision observations from the $Planck$ and BICEP/$Keck$ have imposed stringent bounds on the tensor-to-scalar ratio, ruling out many standard inflationary models. The recent bound from Atacama and SPT along with DESI provides a different viable landscape, making it difficult for the inflationary models to sustain. Amid these increasingly stringent and conflicting observational constraints, modified gravity theories offer a compelling avenue to restore the viability of inflationary models. With this motivation, we study mutated hilltop inflation within $f(\phi ,T)$ gravity, where a scalar field is non-minimally coupled to the trace of the energy-momentum tensor. The scalar spectral index $n_s$, the tensor spectral index $n_t$, and the tensor-to-scalar ratio $r$ are calculated, and their trajectories are presented in the $n_s-r$ plane. The results are then confronted with the latest combined CMB bounds from $Planck$, BICEP/$Keck$, ACT DR6, SPT, and DESI DR2. We report that MHI can predict $r\sim {10}^{-3}$ and is compatible with the latest CMB & DESI bound SPA+BK+DESI at $1\sigma$ CL.