Neutral particle oscillation

In particle physics, neutral particle oscillation is the transmutation of a particle with zero electric charge into another neutral particle due to a change of a non-zero internal quantum number, via an interaction that does not conserve that quantum number. Neutral particle oscillations were first investigated in 1954 by Murray Gell-mann and Abraham Pais. For example, a neutron cannot transmute into an antineutron as that would violate the conservation of baryon number. But in those hypothetical extensions of the Standard Model which include interactions that do not strictly conserve baryon number, neutron–antineutron oscillations are predicted to occur. Such oscillations can be classified into two types: Particle–antiparticle oscillation (for example, _Kaon0 ⇄ _AntiKaon0 oscillation, _B0 ⇄ _antiB0 oscillation, _D0 ⇄ _antiD0 oscillation). Flavor oscillation (for example, _Electron Neutrino ⇄ _Muon Neutrino ⇄ _Tau Neutrino oscillation). In those cases where the particles decay to some final product, then the system is not purely oscillatory, and an interference between oscillation and decay is observed. After the striking evidence for parity violation provided by Wu et al. in 1957, it was assumed that CP (charge conjugation-parity) is the quantity which is conserved. However, in 1964 Cronin and Fitch reported CP violation in the neutral Kaon system. They observed the long-lived KL (with CP = −1 ) undergoing decays into two pions (with CP = [−1]·[−1] = +1 ) thereby violating CP conservation. In 2001, CP violation in the _B0 ⇄ _antiB0 system was confirmed by the BaBar and the Belle experiments. Direct CP violation in the _B0 ⇄ _antiB0 system was reported by both the labs by 2005. The _Kaon0 ⇄ _AntiKaon0 and the _B0 ⇄ _antiB0 systems can be studied as two state systems, considering the particle and its antiparticle as the two states. The pp chain in the sun produces an abundance of _Electron Neutrino. In 1968, R. Davis et al. first reported the results of the Homestake experiment.