Flavon Stabilization in Models with Discrete Flavor Symmetry

We propose a simple mechanism for stabilizing flavon fields with aligned vacuum structure in models with discrete flavor symmetry. The basic idea is that flavons are stabilized by the balance between the negative soft mass and non-renormalizable terms in the potential. We explicitly discuss how our mechanism works in $A_4$ flavor model, and show that the field content is significantly simplified. It also works as a natural solution to the cosmological domain wall problem.Comment: 14 pages, 2 figure

State-of-the-Art Calculation of the Decay Rate of Electroweak Vacuum in Standard Model

The decay rate of the electroweak (EW) vacuum is calculated in the framework of the standard model (SM) of particle physics, using the recent progresses in the understanding of the decay rate of metastable vacuum in gauge theories. We give a manifestly gauge-invariant expression of the decay rate. We also perform a detailed numerical calculation of the decay rate. With the best-fit values of the SM parameters, we find that the decay rate of the EW vacuum per unit volume is about $10^{-554}\ {\rm Gyr^{-1}Gpc^{-3}}$; with the uncertainty in the top mass, the decay rate is estimated as $10^{-284}-10^{-1371}\ {\rm Gyr^{-1}Gpc^{-3}}$.Comment: 5 pages, 1 figure, published versio

Indirect Studies of Electroweakly Interacting Particles at 100 TeV Hadron Colliders

There are many extensions of the standard model that predict the existence of electroweakly interacting massive particles (EWIMPs), in particular in the context of the dark matter. In this paper, we provide a way for indirectly studying EWIMPs through the precise study of the pair production processes of charged leptons or that of a charged lepton and a neutrino at future 100 TeV collider experiments. It is revealed that this search method is suitable in particular for Higgsino, providing us the $5\sigma$ discovery reach of Higgsino in supersymmetric model with mass up to 850 GeV. We also discuss how accurately one can extract the mass, gauge charge, and spin of EWIMPs in our method.Comment: 20 pages, 7 figures, 5 table

Stability of Electroweak Vacuum and Supersymmetric Contribution to Muon g-2

We study the stability of the electroweak vacuum in the supersymmetric (SUSY) standard model (SM), paying particular attention to its relation to the SUSY contribution to the muon anomalous magnetic moment $a_\mu$. If the SUSY contribution to $a_\mu$ is sizable, the electroweak vacuum may become unstable because of enhanced trilinear scalar interactions in particular when the sleptons are heavy. Consequently, assuming enhanced SUSY contribution to $a_\mu$, an upper bound on the slepton masses is obtained. We give a detailed prescription to perform a full one-loop calculation of the decay rate of the electroweak vacuum for the case that the SUSY contribution to $a_\mu$ is enhanced. We also give an upper bound on the slepton masses as a function of the SUSY contribution to $a_\mu$.Comment: 44 pages, 8 figure