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Anomalies and WZW-term of two-flavour QCD

Roland Kaiser
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Abstract

The U(2)_R x U(2)_L symmetry of QCD with two massless flavours is subject to anomalies which affect correlation functions involving the singlet currents A^0_μor V^0_μ. These are relevant for pion-photon interactions, because - for two flavours - the electromagnetic current contains a singlet piece. We give the effective Lagrangian required for the corresponding low energy analysis to next-to-leading order, without invoking an expansion in the mass of the strange quark. In particular, the Wess-Zumino-Witten term that accounts for the two-flavour anomalies within the effective theory is written down in closed form.

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Roland Kaiser. 2000-11-29. Anomalies and WZW-term of two-flavour QCD. https://doi.org/10.1103/physrevd.63.076010

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