Center for Theoretical Physics of the Universe (CTPU)

Precise Determination of Vacuum Decay Rates

by Dr. Yutaro Shoji (Kobayashi-Maskawa Institute for the Origin of Particle and the Universe)

Tuesday, 27 August 2019 from to (Asia/Seoul)
at CTPU Seminar Room
Fourth floor IBS Building, 55, Expo-ro, Yuseong-gu, Daejeon, Korea, 34126
The electroweak vacuum is not absolutely stable in the standard model and various models beyond the standard model. This is due to an appearance of another deeper vacuum, into which the electroweak vacuum can decay. The decay proceeds through quantum tunneling and the rate is expressed with an exponential suppression factor and a pre-factor. The suppression factor has been calculated in many papers, but a naive dimensional analysis has been usually adopted for the pre-factor.We have pointed out that such an evaluation can suffer from large quantum corrections and it is important to calculate the pre-factor as well. To calculate the pre-factor, we had problems in a gauge sector; its gauge invariance is not explicitly shown, and there appear zero modes, which we could not deal with. We have solved these problems and made it possible to determine vacuum decay rates precisely. As applications, we analyzed the decay rates in the standard model and its fermionic extensions.