Observational viability of anisotropic inflation revisited

We investigate anisotropic inflation within the single-field model featuring an intermediate scale factor. Our analysis reveals that the anisotropic nature of the Friedmann equations in this framework affects the slow-roll parameters, which in turn influence key perturbation parameters. Using a numerical approach, we derive constraints on the intermediate parameter beta and the anisotropic parameter c. Our results show that the model is consistent with Planck2018 TT, TE, EE +lowE+lensing+BK14+BAO data at 68% CL, for 0.84 < beta < 1 and 7.34 < c < 27.7. At 95% CL the consistency holds for 0.77 < beta < 1 and 7.17 < c < 28.9. The model is also consistent with Planck2018 TT, TE, EE +lowE+lensing+BK18+BAO data, for 0.91 < beta < 1 and 8.00 < c < 27.4 (at 68% CL), and 0.88 < beta < 1 and 7.40 < c < 28.8 (at 95% CL). Additionally, we examine the reheating phase using these constraints on constraints on beta and c and determine the observationally consistent ranges for the number of e-folds and the temperature during the reheating phase.