Local Decay for Weak Interactions with Massless Particles
  We consider a mathematical model for the weak decay of the intermediate boson $Z^0$ into neutrinos and antineutrinos. We prove that the total Hamiltonian has a unique ground state in Fock space and we establish a limiting absorption principle, local decay and a property of relaxation to the ground state for initial states and observables suitably localized in energy and position. Our proofs rest, in particular, on Mourre's theory and a low-energy decomposition. 
Jean-Marie Barbaroux, J\'er\'emy Faupin, Jean-Claude Guillot
math-ph math.MP math.SP