False Vacuum Decay Induced by Particle Collisions

The semiclassical formalism for numerical calculation of the rate of tunneling transitions induced by N particles with total energy E of order or higher than the height of the barrier is developed. The formalism is applied to the induced false vacuum decay in the massive four-dimensional −λφ model. The decay rate, as a function of E and N , is calculated numerically in the range 0.4 ∼< E/Esph ∼< 3.5 and 0.25 ∼< N/Nsph ∼< 1.0, where Esph and Nsph are the energy and the number of particles in the analog of the sphaleron configuration. The results imply that the two-particle cross section of the false vacuum decay is exponentially suppressed at least up to energies of order 10Esph. At E ∼ Esph, this exponential suppression is estimated as about 80% of the zero energy suppression.