Implications of the scalar tilt for the tensor-to-scalar ratio

PAOLO CREMINELLI; SERGEI DUBOVSKY; DIANA LOPEZ NACIR; MARKO SIMONOVIC; GABRIELE TREVISAN; MATIAS ZALDARRIAGA

PHYSICAL REVIEW D - PARTICLE AND FILDS

AMER PHYSICAL SOC

Lugar: NEW YORK; Año: 2015 vol. 92 p. 281 - 285

0556-2821

We investigate the possible implications of the measured value of the scalar tilt ns for the tensor-to-scalar ratio r in slow-roll, single-field inflationary models. The measured value of the tilt satisfies ns − 1 ∼ 1/N0, where N0 ∼ 60 is the number of e-folds for observationally relevant scales. If this is not a coincidence and the scaling holds for different values of N, it strongly suggests that either r is as big as 10^(−1) (a possibility in tension with the recent data), or smaller than 10^(−2) and exponentially dependent on ns. A large region of the (ns, r) plane is not compatible with this scaling.