# I Charge conjugation of Majorana pairs

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1. Mar 19, 2016

### Andrea M.

I was reading this article (http://arxiv.org/abs/1301.0021) about WIMP pair annihilation. At page six the author says that under charge conjugation a state of Majorana particles with orbital angular momentum $L$ and spin angular momentum $S$ take a phase $(-1)^{L+S}$. I understand this for system of particle-antiparticle because under C the particle go into the antiparticle and vice versa so the spatial and spin wave functions give respectively a phase $(-1)^L$ and $(-1)^{S+1}$ on top of this the intrinsic parities give another $(-1)$ factor so we get the total phase factor $(-1)^{L+S}$. But for Majorana two particles system under charge conjugation, being no distinction between particle and antiparticle, I expect than nothing happens under charge conjugation so that the system is CP even independently from the values of $L$ and $S$. Where I'm wrong?

2. Mar 24, 2016