Natural tuning: towards a proof of concept

• Published in: The journal of high energy physics Vol. 2013; no. 9; pp. 1 - 24
• Main Authors: Dubovsky, Sergei, Gorbenko, Victor, Mirbabayi, Mehrdad
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2013; Springer Nature B.V
• Subjects: Asymptotic properties; Classical and Quantum Gravitation; Construction; Cosmological constant; Elementary Particles; Fragility; Gravitation theory; High energy physics; Physics; Physics and Astronomy; Proving; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Relativity Theory; Scalars; String Theory; Tuning; Exact S-Matrix; Standard Model; Models of Quantum Gravity
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP09(2013)045

A bstract The cosmological constant problem and the absence of new natural physics at the electroweak scale, if confirmed by the LHC, may either indicate that the nature is fine-tuned or that a refined notion of naturalness is required. We construct a family of toy UV complete quantum theories providing a proof of concept for the second possibility. Low energy physics is described by a tuned effective field theory, which exhibits relevant interactions not protected by any symmetries and separated by an arbitrary large mass gap from the new “gravitational” physics, represented by a set of irrelevant operators. Nevertheless, the only available language to describe dynamics at all energy scales does not require any fine-tuning. The interesting novel feature of this construction is that UV physics is not described by a fixed point, but rather exhibits asymptotic fragility. Observation of additional unprotected scalars at the LHC would be a smoking gun for this scenario. Natural tuning also favors TeV scale unification.