Understanding Proton Decay: College Physics Help

[Breo]

It is an old textbook in russian: Particle physics and Symmetries - Svörtynsky

The problem says:

Of all the fermion bilinears (scalar, pseudoscalar, vector, axialvector and tensor), which of them cancel for a Majorana fermion such that $\psi = \psi^c$? Does a kinetic term of the form $\bar{\psi}\gamma_{\mu}\partial^{\mu}\psi^c$ cancel?

 

[mfb]

@Breo: open a new thread for a new question please.

 

[Breo]

I still do not understand one thing. Probably is a small misconception.

If protons are generally considered to be stable because the baryon number symmetry protects them, but it is broken in the Standard Model at the quantum level (chiral anomaly, but still SM), why we still say that protons are stable in SM? (forget about GUTs)

 

[magnetic flux]

In last week's seminar, a professor said that the chiral anomaly will lead to a lifetime of $10^{70}$ years.

From this I conclude the following: The SU(5) GUT have lifetimes of sometimes less than $10^{35}$ years. Therefore the difference is so large, that one can consider the protons stable even with the chiral anomaly in the standard model.

 

[ChrisVer]

zombie post...