Hi, I was reading a lecture of qft and I found that two equations:(adsbygoogle = window.adsbygoogle || []).push({});

[tex]

\begin{flalign*}

i \gamma^\mu \partial_\mu\psi_R - m\psi_L=0 \\

i \gamma^\mu \partial_\mu\psi_L - m\psi_R=0

\end{flalign*}

[/tex]

after splitting in two Dirac's equation with Weyl's projectors.

I found that really interesting that the coupling between the two chiralities is made by the mass term and that a massless fermion would have a symmetry U(1)xU(1) with one parameter for each helicity. But I would like to know if it has a much profound signification that the restriction to one symmetry is due to the mass.

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# Fermions with no mass, and helicity coupling.

Can you offer guidance or do you also need help?

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