Charge Conjugation


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Related to Charge Conjugation: Charge Parity

Charge Conjugation

 

the operation of exchanging all particles that participate in any interaction for their corresponding antiparticles. Experience shows that strong interactions and electromagnetic interactions do not change upon charge conjugation; that is, strong and electromagnetic interactions between particles and corresponding antiparticles in the same state are identical. For example, the electromagnetic interaction of two positrons (or antiprotons) is exactly the same as that between two electrons (or protons). This means that for any process that takes place with some particles under the influence of strong or electromagnetic interaction, there exists exactly the same process for their antiparticles.

Weak interactions, in contrast to strong and electromagnetic interactions, change on charge conjugation. Symmetry between “right” and “left” directions in space (mirror symmetry) is also absent in processes of weak interaction. On violation of charge and mirror symmetry taken separately, there exists in weak interactions (at least to an accuracy of 0.1 percent) a symmetry with respect to the simultaneous accomplishment of both operations—charge conjugation and specular reflection: a process that transpires with some antiparticles as a result of weak interaction is a sort of mirror image of the analogous process that takes place with the particles.

S. S. GERSHTEIN

References in periodicals archive ?
We can summarize the quaternionic physical quantities of dual MHD fields and their changes under charge conjugation, parity inversion, and time reversal given by Table 2 [53, 54].
Norbury, "The invariance of classical electromagnetism under charge conjugation, parity and time reversal (CPT) transformations," European Journal of Physics, vol.
Physical quantities Charge conjugation (C) [[partial derivative].sub.t] [[partial derivative].sub.t] [nabla] [nabla] [a.sub.0] [a.sub.0] [J.sup.e] -[J.sup.e] [J.sup.m] -[J.sup.m] E -E B -B [[rho].sup.e] -[[rho].sup.e] [[rho].sup.m] [[rho].sup.m] Physical quantities Parity inversion (P) [[partial derivative].sub.t] [[partial derivative].sub.t] [nabla] -[nabla] [a.sub.0] -[a.sub.0] [J.sup.e] -[J.sup.e] [J.sup.m] [J.sup.m] E -E B B [[rho].sup.e] [[rho].sup.e] [[rho].sup.m] -[[rho].sup.m] Physical quantities Time reversal (T) [[partial derivative].sub.t] -[[partial derivative].sub.t] [nabla] [nabla] [a.sub.0] -[a.sub.0] [J.sup.e] -[J.sup.e] [J.sup.m] [J.sup.m] E E B B [[rho].sup.e] [[rho].sup.e] [[rho].sup.m] [[rho].sup.m]
Since the corresponding antiparticles should possess a Compton radius like their particle counterparts, the C' operator is not a valid charge conjugation operator.
If it is assumed, however, that the charge conjugation operator C applies to both the free-space particle charge and the PV charge doublet, then (2) and (3) yield
The corresponding positron equation of motion is then obtained from the charge conjugation of (9)
In the case of Dirac bispinor (1/2,0) [direct sum] (0,1/2) C is charge conjugation operator.
Then, we redefine the H-quark fields (the fermion chirality is changed by the charge conjugation):
Thus, we have constructed the right-handed field partner of the first generation, using the second generation of the left-handed fields in two steps: charge conjugation and redefinition.
At the fundamental level, the Lagrangian of the current H-quarks (10) is invariant under modified charge conjugation of the H-quark fields (hyper-G-parity, HG-parity) which is defined as follows:
where C is the charge conjugation, a, b are isotopic indices, and [a.bar], [b.bar] are hypercolor indices (it is the same notation as in the Section 2).
So, the invariance condition results in the transformation [[??].sup.HG.sub.k] = -[[??].sub.k], that is, [??] is odd, while the SM fields are even under modified charge conjugation (44).