Constraints on non-canonical chaotic inflation from ACT DR6 and BICEP/Keck data

In this study, we precisely evaluated the feasibility of the chaotic inflation model within a non-canonical kinetic framework. By applying the slow-roll approximation and imposing constraints on the equilateral non-Gaussianity $f_{\mathrm{N}\mathrm{L}}^{\mathrm{e}\mathrm{q}\mathrm{u}\mathrm{i}\mathrm{l}}$, we imposed constraints on the feasible range of the potential index $n$. We established physical bounds for the non-canonical parameter $\alpha$. To obtain precise parameter constraints, we solved the primordial perturbation equations numerically and conducted a rigorous MCMC analysis by using a comprehensive joint P-ACT-LB-BK18 dataset. For these potentials $n=1\mathrm{/}3$, $2\mathrm{/}3$, and $1$, our results respectively tightly limit $\alpha$ to the levels of $8.8_{-2.8}^{+1.6}$, $11.7_{-2.6}^{+1.7}$, and $16.4_{-7.0}^{+3.7}$, within the corresponding $1\sigma$ confidence intervals. Meanwhile, the required number of $e$-foldings naturally converges to $N\simeq 54$, without the need for fine-tuning. These findings confirm that non-standard mechanisms can resurrect excluded chaotic inflation models within the $1\sigma$ allowed regions of high-precision cosmological data.