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

Paolo Creminelli, Sergei Dubovsky, Diana López Nacir, Marko Simonović, Gabriele Trevisan, Giovanni Villadoro, Matias Zaldarriaga

    Research output: Contribution to journalArticlepeer-review


    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/N∗, where N∗∼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.

    Original languageEnglish (US)
    Article number123528
    JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
    Issue number12
    StatePublished - Dec 23 2015

    ASJC Scopus subject areas

    • Nuclear and High Energy Physics
    • Physics and Astronomy (miscellaneous)


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