Chargino contributions in light of recent ϵ′/ϵ

Abstract

Recently, the standard model prediction of ϵ′/ϵ was improved, and a discrepancy from the experimental results was reported at the 2.9σ level. We study the chargino contributions to Z penguin especially with the vacuum stability constraint. The vacuum decay rate is investigated, and it is shown that the discrepancy can be explained if superparticles are lighter than 4–6 TeV. Correlations with B(KL→π0νν¯) and other experimental constraints are also discussed.