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arXiv · 1403.2606

Trace anomalies in chiral theories revisited

Loriano Bonora·Stefano Giaccari·Bruno Lima de Souza
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Abstract

Motivated by the search for possible CP violating terms in the trace of the energy-momentum tensor in theories coupled to gravity we revisit the problem of trace anomalies in chiral theories. We recalculate the latter and ascertain that in the trace of the energy-momentum tensor of theories with chiral fermions at one-loop the Pontryagin density appears with an imaginary coefficient. We argue that this may break unitarity, in which case the trace anomaly has to be used as a selective criterion for theories, analogous to the chiral anomalies in gauge theories. We analyze some remarkable consequences of this fact, that seem to have been overlooked in the literature.

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Loriano Bonora, Stefano Giaccari, Bruno Lima de Souza. 2014-08-29. Trace anomalies in chiral theories revisited. https://doi.org/10.1007/jhep07(2014)117

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