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.
|Titolo:||Trace anomalies in chiral theories revisited|
|Autori:||Bonora L.; Giaccari S.; Lima de Souza B.|
|Rivista:||JOURNAL OF HIGH ENERGY PHYSICS|
|Data di pubblicazione:||2014|
|Digital Object Identifier (DOI):||10.1007/JHEP07(2014)117|
|Fulltext via DOI:||10.1007/JHEP07(2014)117|
|Appare nelle tipologie:||1.1 Journal article|