Year: 2018
Type: dissertation
Abstract: The stability problem of the electroweak vacuum has been theoretically discussed and widely investigated for quite a long time.However, the recent measurements of the Higgs boson mass m h and the top quark mass m t strongly suggest that the current Higgs vacuum is not stable and would eventually decay into a true Planck-scale vacuum.From the standard analysis of the instanton method with the best fit values of parameters of the Standard Model, the lifetime of the electroweak vacuum exceeds that of the Universe.Therefore, it was thought that the metastability of the Higgs vacuum does not have any serious impact on the observed Universe.However, the situation drastically changes when the quantum influence of the gravity can not be ignored.In particular, whether cosmological inflation of the early Universe or evaporations of the black holes are compatible with the stability problem of the Higgs vacuum has recently attracted significant interest in the high-energy community.In this thesis, I summarize my past research in which I have done so far mainly on the Higgs vacuum stability in gravitational background or cosmological situations.The central issue for this research theme is how gravitationally induced Higgs fluctuation affects the stability of the electroweak vacuum.By using some techniques of quantum field theory in curved spacetime which is consistent with the semiclassical approach of quantum gravity, we derive gravitationally induced vacuum fluctuation and standard effective potential in curved spacetime.However, we clearly show that the induced vacuum fluctuation modifies the standard effective potential [1,2] and the spacetime itself as the gravitational backreaction [3].Based on the formulation, we investigate the electroweak vacuum stability in various background spacetimes or cosmological situations as during inflation corresponding to the de-Sitter spacetime [1,2], after inflation like the preheating or reheating stage [4] and around evaporating black holes [5].
Authors: 松井, 宏樹, マツイ, ヒロキ, MATSUI, Hiroki
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7144768740