Is a Higgs vacuum instability fatal for high-scale inflation?

Journal Article · Thu Jun 25 00:00:00 EDT 2015 · Physical Review. D, Particles, Fields, Gravitation and Cosmology

DOI:https://doi.org/10.1103/PhysRevD.91.123537· OSTI ID:1226319

Kearney, John ^[1]; Yoo, Hojin ^[2]; Zurek, Kathryn M. ^[2]

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1. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)

We study the inflationary evolution of a scalar field h with an unstable potential for the case where the Hubble parameter H during inflation is larger than the instability scale Λ_I of the potential. Quantum fluctuations in the field of size δh ~ H/2π imply that the unstable part of the potential is sampled during inflation. We investigate the evolution of these fluctuations to the unstable regime and in particular whether they generate cosmological defects or even terminate inflation. We apply the results of a toy scalar model to the case of the Standard Model (SM) Higgs boson, the quartic of which evolves to negative values at high scales, and extend previous analyses of Higgs dynamics during inflation utilizing statistical methods to a perturbative and fully gauge-invariant formulation. We show that the dynamics are controlled by the renormalization group-improved quartic coupling λ(μ) evaluated at a scale μ = H, such that Higgs fluctuations are enhanced by the instability if H > Λ_I. Even if H > Λ_I, the instability in the Standard Model Higgs potential does not end inflation; instead the universe slowly sloughs off crunching patches of space that never come to dominate the evolution. As inflation proceeds past 50 e-folds, a significant proportion of patches exits inflation in the unstable vacuum, and as much as 1% of the spacetime can rapidly evolve to a defect. Depending on the nature of these defects, however, the resulting universe could still be compatible with ours.

• Research Organization: Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: AC02-07CH11359; AC02-05CH11231; SC0007859
• OSTI ID: 1226319
• Alternate ID(s): OSTI ID: 1198521
• Report Number(s): FERMILAB-PUB-15-090-T; PRVDAQ; arXiv eprint number arXiv:1503.05193
• Journal Information: Physical Review. D, Particles, Fields, Gravitation and Cosmology, Vol. 91, Issue 12; ISSN 1550-7998
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS