Testing non-minimally coupled inflation with CMB data: a Bayesian analaysis

We use the most recent cosmic microwave background (CMB) data to perform a Bayesian statistical analysis and discuss the observational viability of inflationary models with a non- minimal coupling, xi, between the inflaton fi eld and the Ricci scalar. We particularize our analysis to two examples of small and large fi eld inflationary models, namely, the Coleman- Weinberg and the chaotic quartic potentials. We fi nd that (i) the xi parameter is closely correlated with the primordial amplitude; (i i) although improving the agreement with the CMB data in the r- n(s) plane, where r is the tensor- to- scalar ratio and n s the primordial spectral index, a non- null coupling is strongly disfavoured with respect to the minimally coupled standard xi CDM model, since the upper bounds of the Bayes factor (odds) for xi parameter are greater than 150 : 1.