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Crunching away the cosmological constant problem: dynamical selection of a small Λ by Itay M. Bloch; Csaba Csáki; Michael Geller; Tomer Volansky is a Physics and Astronomy article available to read on EtoBox.

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## Abstract We propose a novel explanation for the smallness of the observed cosmological constant (CC). Regions of space with a large CC are short lived and are dynamically driven to crunch soon after the end of inflation. Conversely, regions with a small CC are metastable and long lived and are the only ones to survive until late times. While the mechanism assumes many domains with different CC values, it does not result in eternal inflation nor does it require a long period of inflation to populate them. We present a concrete dynamical model, based on a super-cooled first order phase transition in a hidden conformal sector, that may successfully implement such a crunching mechanism. We find that the mechanism can only solve the CC problem up to the weak scale, above which new physics, such as supersymmetry, is needed to solve the CC problem all the way to the UV cutoff scale. The absence of experimental evidence for such new physics already implies a mild little hierarchy problem for the CC. Curiously, in this approach the weak scale arises as the geometric mean of the temperature in our universe today and the Planck scale, hinting at a new “CC miracle”, motivating new physics a

Who reads Crunching away the cosmological constant problem: dynamical selection of a small Λ?

Author

Itay M. Bloch; Csaba Csáki; Michael Geller; Tomer Volansky

Publisher

Springer Science and Business Media LLC

Published

2020

Language

EN

Field

Physics and Astronomy (Physical Sciences)