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EDIT: Completely rewritten because of the 'needs clarity' tag and some useful related questions appearing in the side-bar. I hope this is clear now

This answer gives a long list of properties of particles whose value differs by a minus sign when comparing a particle to its antiparticle. We know that anti-particles exist, so apparently for every particle there is a particle where the value of all the properties in this list are 'flipped': i.e. the same magnitude but of opposite sign.

My question is: given a particle, say an electron, does there exist a different particle where some of the properties in the list in the linked answer are flipped and some are not?

If the answer is no, why is this not possible?

If the answer is yes, what is an example of such a pair of particles?

Vincent
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1 Answers1

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All charge-like quantum numbers flip upon a change of a particle to an anti-particle. In other words, charge-like quantum numbers are correlated.

It is not like that one has a distinct particle with Lepton number +1 and another one with Lepton number -1 and each has a distinct anti-particle. The particle with Lepton number -1 is the anti-particle of the particle of Lepton number +1.

This is the same for particles with non-zero Baryon number and so on.

EDIT

Actually, there exist also particles which are their own anti-particle. The most prominent one is the photon. In the standard model there exist only one photon with no partners or anti partners.

In a wider sense also triplets exist, for instance $\pi^+$, $\pi^0$ and $\pi^{-}$. They form a triplet in the vector representation of SU(2). But in a strict sense $\pi^0$ has nothing to do with $\pi^+$ and $\pi^{-}$ which are anti-particles of each other. Because the mass of $\pi^0$ has not the same mass as a $\pi^{\pm}$. In the pure viewpoint of particle-antiparticle symmetry the $\pi^0$ is not part of $\pi^{\pm}$. The $\pi^0$ is anti-particle of its own like the photon. In particular there is nothing to flip. Because the number one might want to flip is zero.

Needless to say, this applies for the standard model, i.e. the actual valid description for elementary particles which has been successfully checked in many experiments. Hypothetical theories are not considered here.

Lagrangian
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