The $\pi \pi \to \pi {\gamma }^{\star }$ amplitude and the resonant $\rho \to \pi {\gamma }^{\star }$ transition from lattice QCD

Raúl A. Briceño, Jozef J. Dudek, Robert G. Edwards +3

We present a determination of the $P$-wave $\pi \pi \to \pi {\gamma }^{\star }$ transition amplitude from lattice quantum chromodynamics. Matrix elements of the vector current in a finite-volume are ex…