2019 Impact factor 4.389
Particles and Fields
Eur. Phys. J. C 9, 409-411
DOI 10.1007/s100529900041

Mixing of two-level unstable systems

G. López Castro1 - J.H. Muñoz1,2 - J. Pestieau3

1 Departamento Física, Centro de Investigación y de Estudios, Avanzados del IPN, Apdo. Postal 14-740, 07000 México, D.F., México
2 Departamento de Física, Universidad del Tolima, A.A. 546, Ibagué, Colombia
3 Institut de Physique Théorique, Université Catholique de Louvain, 2 Ch. du Cyclotron, B-1348 Louvain-la-Neuve, Belgium

Received: 15 December 1998 / Published online: 28 May 1999

Abstract
Unstable particles can be consistently described in the framework of quantum field theory. Starting from the full S matrix amplitudes of $B^+ \rightarrow (2\pi,\ 3\pi) l^+ \nu$ decays as examples of processes where the $\rho-\omega$ resonances dominate, we propose a prescription for the mixing of two "quasi-physical'' unstable states that differs from the one obtained from the diagonalization of the $M-\mathrm{i}\Gamma/2$ non-Hermitian Hamiltonian. We discuss some important consequences for CP violation in the KL-KS system.


Copyright Springer-Verlag