Ijjas, AnnaSteinhardt, Paul J.Loeb, Abraham2019-10-032013Ijjas, Anna, Paul J. Steinhardt, and Abraham Loeb. 2013. “Inflationary Paradigm in Trouble after Planck2013.” Physics Letters B 723 (4–5): 261–66. https://doi.org/10.1016/j.physletb.2013.05.023.0370-26931873-2445http://nrs.harvard.edu/urn-3:HUL.InstRepos:41461284Recent results from the Planck satellite combined with earlier observations from WMAP, ACT, SPT and other experiments eliminate a wide spectrum of more complex inflationary models and favor models with a single scalar field, as reported by the Planck Collaboration. More important, though, is that all the simplest inflaton models are disfavored statistically relative to those with plateau-like potentials. We discuss how a restriction to plateau-like models has three independent serious drawbacks: it exacerbates both the initial conditions problem and the multiverse-unpredictability problem and it creates a new difficulty that we call the inflationary "unlikeliness problem." Finally, we comment on problems reconciling inflation with a standard model Higgs, as suggested by recent LHC results. In sum, we find that recent experimental data disfavors all the best-motivated inflationary scenarios and introduces new, serious difficulties that cut to the core of the inflationary paradigm. Forthcoming searches for B-modes, non-Gaussianity and new particles should be decisive.en-USJournal Article2019-10-0310.1016/j.physletb.2013.05.023