Calculating the Two-photon Contribution to π⁰ → e⁺ e^- Decay Amplitude

2020/01/16 by Norman H. Christ, Christ, Norman H., Xu Feng +7
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #hep-lat

paper · pdf · doi:10.48550/arxiv.2001.05642

7 pages, 4 figures, Proceedings of the 37th Annual International Symposium on Lattice Field Theory (Lattice 2019), 16-22 June 2019, Wuhan, China

arxiv created 2020/01/16 · arxiv updated 2020/01/17

Abstract

We develop a new method that allows us to deal with two-photon intermediate states in a lattice QCD calculation. We apply this method to perform a first-principles calculation of the π⁰ → e⁺ e^- decay amplitude. Both the real and imaginary parts of amplitude are calculated. The imaginary part is compared with the prediction of optical theorem to demonstrate the effectiveness of this method. Our result for the real part of decay amplitude is 19.68(52)(1.10) eV, where the first error is statistical and the second is systematic.

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