Бейтарап бөлшектердің кванттық механикалық түрленуі

Quantum mechanical transmutation of neutral particles
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, oscillation). Flavor oscillation (for example, 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. Direct CP violation in the system was reported by both the labs by 2005. The and the systems can be studied as two state systems, considering the particle and its antiparticle as the two states.

If in a system and represent CP conjugate states (i. e. particle antiparticle) of one another (i. e. and ), and certain other conditions are met, then CP violation can be observed as a result of this phenomenon. Depending on the condition, CP violation can be classified into three types:

The above description refers to flavor (or strangeness) eigenstates and energy (or CP) eigenstates. But which of them represents the "real" particle? What do we really detect in a laboratory? Quoting David J. Griffiths:

If the system is a three state system (for example, three species of neutrinos , three species of quarks ), then, just like in the two state system, the flavor eigenstates (say , , ) are written as a linear combination of the energy (mass) eigenstates (say , , ). That is,

In case of leptons (neutrinos for example) the transformation matrix is the PMNS matrix, and for quarks it is the CKM matrix. The off diagonal terms of the transformation matrix represent coupling, and unequal diagonal terms imply mixing between the three states. The transformation matrix is unitary and appropriate parameterization (depending on whether it is the CKM or PMNS matrix) is done and the values of the parameters determined experimentally.