TwInflation

Journal of High Energy Physics

Soubhik Kumar¹  Kaustubh Deshpande²  Raman Sundrum² 

[1] Berkeley Center for Theoretical Physics, Department of Physics, University of California, 94720, Berkeley, CA, USA;Theoretical Physics Group, Lawrence Berkeley National Laboratory, 94720, Berkeley, CA, USA;Maryland Center for Fundamental Physics, Department of Physics, University of Maryland, 20742, College park, MD, USA;

关键词: Cosmology of Theories beyond the SM;    Discrete Symmetries;    Effective Field Theories;    Global Symmetries;   

DOI  :  10.1007/JHEP07(2021)147

来源: Springer

【 摘 要 】

The general structure of Hybrid Inflation remains a very well-motivated mechanism for lower-scale cosmic inflation in the face of improving constraints on the tensor-to-scalar ratio. However, as originally modeled, the “waterfall” field in this mechanism gives rise to a hierarchy problem (η−problem) for the inflaton after demanding standard effective field theory (EFT) control. We modify the hybrid mechanism and incorporate a discrete “twin” symmetry, thereby yielding a viable, natural and EFT-controlled model of non-supersymmetric low-scale inflation, “Twinflation”. Analogously to Twin Higgs models, the discrete exchange-symmetry with a “twin” sector reduces quadratic sensitivity in the inflationary potential to ultra-violet physics, at the root of the hierarchy problem. The observed phase of inflation takes place on a hilltop-like potential but without fine-tuning of the initial inflaton position in field-space. We also show that all parameters of the model can take natural values, below any associated EFT-cutoff mass scales and field values, thus ensuring straightforward theoretical control. We discuss the basic phenomenological considerations and constraints, as well as possible future directions.

【 授权许可】

CC BY