Anomalies in String-inspired Non-local Extensions of QED

TL;DR

This paper explores anomalies in string-inspired non-local extensions of QED, showing gauge invariance is preserved while chiral anomalies depend on fermion mass and non-locality scale.

Contribution

It provides explicit calculations of vector and chiral anomalies in a novel non-local QED model inspired by string theory and quantum gravity approaches.

Findings

Vector anomaly vanishes, respecting gauge invariance.

Chiral anomaly vanishes for massless fermions but not for massive ones.

Results applied to  ightarrow \u03b33 decay.

Abstract

We investigate anomalies in the class of non-local field theories that have been proposed as an ultraviolet completion of 4-D Quantum Field Theory (QFT) with generalizing the kinetic energy operators to an infinite series of higher derivatives inspired by string field theory and ghost-free non-local approaches to quantum gravity. We explicitly calculate the vector and chiral anomalies in a string-inspired non-local extension of QED. We show that the vector anomaly vanishes as required by gauge-invariance and the Ward identity. On the other hand, although the chiral anomaly vanishes to the leading order with massless fermions, it nonetheless does not vanish with the massive fermions and we calculate it to the leading order in scale of non-locality. We also calculate the non-local vector and axial currents explicitly, and present an illustrative example by applying our results to the decay of \pi_0 \rightarrow \gamma\gamma.