Cosmic-ray induced vacuum decay in the standard model

In the standard model, if the Higgs boson mass, mH, and the top quark mass, mt, satisfy the relationship mt > or approx. 95 GeV + 0.60 mH, then the vacuum is unstable. However, if the top quark mass is less than 190 GeV, then the lifetime is greater than the age of the universe. There is thus a large region of parameter space in which the vacuum is unstable, but sufficiently long-lived. We examine the possibility that high energy cosmic ray collisions could induce the decay of the vacuum, and show that this region of parameter space can be excluded. (orig.)