1. Resonant π+γ → π+π0 Amplitude from Quantum Chromodynamics.
- Author
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Briceño, Raúl A., Dudek, Jozef J., Edwards, Robert G., Shultz, Christian J., Thomas, Christopher E., and Wilson, David J.
- Subjects
- *
QUANTUM chromodynamics , *HADRONS , *QUARKS , *PHASE shift (Nuclear physics) , *ELECTROMAGNETIC fields - Abstract
We present the first ab initio calculation of a radiative transition of a hadronic resonance within quantum chromodynamics (QCD). We compute the amplitude for nn ππ→πγ*, as a function of the energy of the nn pair and the virtuality of the photon, in the kinematic regime where nn couples strongly to the unstable p resonance. This exploratory calculation is performed using a lattice discretization of QCD with quark masses corresponding to mπ ≈ 400 MeV. We obtain a description of the energy dependence of the transition amplitude, constrained at 48 kinematic points, that we can analytically continue to the p pole and identify from its residue the ρ → πγ* form factor. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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