# I Beta decay and CPT symmetry

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1. Jun 19, 2016

### entropy1

I read that CP-symmetry violation occurs (or can occur) in beta decay. Does that mean that, since CPT-symmetry must hold, there is no T-symmetry?

2. Jun 19, 2016

### Paul Colby

yes, within LQFT which appears to be our most complete theory.

3. Jun 20, 2016

### vanhees71

One should note that the violation of P, CP, and T symmetry are all shown directly by observation, most recently the T violation in B decays by the BABAR collaboration. I'm to lazy to google for it. The usual kind of relativistic QT, i.e., local relativistic QFT with a stable ground state, predicts CPT invariance, which so far has not been observerd to be violated.