2016/10/31 by Kiwoon Choi, Sang Hui Im · 50 citations
Physics and Astronomy · #Cosmological constant #Cosmology #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Hierarchy problem #Hubble's law #Large extra dimension #Parameter space #Particle physics theoretical and experimental studies #Phenomenology (philosophy) #Physics beyond the Standard Model #Standard Model (mathematical formulation) #astro-ph.CO #hep-ph
paper · pdf · doi:10.1007/jhep12(2016)093
published in Journal of High Energy Physics 2016(12) (Springer Nature) · 27 pages, 4 figures; v4: a minor typo correction
openalex created_date 2016/10/14 · openalex publication_date 2016/12/01 · arxiv created 2017/01/02 · arxiv updated 2017/01/03 · openalex updated_date 2026/08/05
We examine the low energy phenomenology of the relaxion solution to the weak scale hierarchy problem. Assuming that the Hubble friction is responsible for a dissipation of the relaxion energy, we identify the cosmological relaxion window which corresponds to the parameter region compatible with a given value of the acceptable number of inflationary e-foldings. We then discuss a variety of observational constraints on the relaxion window, including those from astrophysical and cosmological considerations. We find that majority of the parameter space with a relaxion mass m ϕ ≳ 100 eV or a relaxion decay constant f ≲107GeV is excluded by existing constraints. There is an interesting parameter region with m ϕ ∼ 0.2 − 10 GeV and f ∼ few − 200 TeV, which is allowed by existing constraints, but can be probed soon by future beam dump experiments such as the SHiP experiment, or by improved EDM experiments.