Supersymmetry is the most natural framework for physics above the TeV scale, and the corresponding framework for early-Universe cosmology, including inflation, is supergravity. No-scale supergravity emerges from generic string compactifications and yields a non-negative potential, and is therefore a plausible framework for constructing models of inflation. No-scale inflation yields naturally predictions similar to those of the Starobinsky model based on R + R2 gravity, with a tilted spectrum of scalar perturbations: ns ∼ 0.96, and small values of the tensor-to-scalar perturbation ratio r < 0.1, as favoured by Planck and other data on the cosmic microwave background (CMB). Detailed measurements of the CMB may provide insights into the embedding of inflation within string theory as well as its links to collider physics.
Bibliographical noteFunding Information:
The work of JE was supported in part by the London Centre for Terauniverse Studies (LCTS), using funding from the European Research Council via the Advanced Investigator Grant 267352 and from the UK STFC via the research grant ST/L000326/1. The work of DVN. was supported in part by the DOE grant DE-FG03-95-ER-40917 and in part by the Alexander S Onassis Public Benefit Foundation. The work of MAGG and K.A.O. was supported in part by DOE grant DE-SC0011842 at the University of Minnesota.
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