Radiative-corrected Higgs inflation in light of the latest ACT observations
Jureeporn Yuennan, Farruh Atamurotov, Phongpichit Channuie
Abstract
Recent measurements from the Atacama Cosmology Telescope (ACT), particularly when combined with DESI baryon acoustic oscillation data, have reported a scalar spectral index n s slightly higher than that inferred by Planck 2018, suggesting a mild tension with the predictions of standard inflationary attractor models. In this work, we revisit the quantum-corrected Higgs inflation scenario within the framework of a non-minimally coupled scalar field theory. Starting from the one-loop effective action, we incorporate radiative corrections through the anomalous scaling parameter A I and derive analytic expressions for the inflationary observables n s and r in the Einstein frame. Our analysis demonstrates that quantum corrections naturally shift n s toward higher values while keeping the tensor-to-scalar ratio r suppressed. For N = 60 , the model predicts n s ≃ 0.9743 and r ≃ 5.4 × 10 − 3 , in excellent agreement with the latest ACT+DESI (P-ACT-LB) data and fully consistent with the Planck 2018 limit r < 0.036. The derived constraint 4.36 × 10 − 10 < λ / ξ 2 < 10.77 × 10 − 10 confirms the robustness of the quantum-corrected Higgs framework and indicates that near-future CMB polarization experiments such as CORE, AliCPT, LiteBIRD, and CMB-S4 will be able to probe the predicted parameter space with high precision.