Document Type


Publication Date




Publication Title

Physical Review D






114508 (1-20)


We present a determination of the P-wave πœ‹πœ‹ β†’ πœ‹π›Ύβ‹† transition amplitude from lattice quantum chromodynamics. Matrix elements of the vector current in a finite volume are extracted from three-point correlation functions, and from these we determine the infinite-volume amplitude using a generalization of the Lellouch-LΓΌscher formalism. We determine the amplitude for a range of discrete values of the πœ‹πœ‹ energy and virtuality of the photon and observe the expected dynamical enhancement due to the ρ resonance. Describing the energy dependence of the amplitude, we are able to analytically continue into the complex energy plane and from the residue at the ρ pole extract the ρ β†’ πœ‹π›Ύβ‹† transition form factor. This calculation, at mπœ‹ β‰ˆ 400  MeV, is the first to determine the form factor of an unstable hadron within a first principles approach to QCD.


Β© 2016 American Physical Society

"Yes, the author or the author's employer may use all or part of the APS published article, including the APS-prepared version (e.g., the PDF from the online journal) without revision or modification, on the author's or employer's website as long as a fee is not charged. If a fee is charged, then APS permission must be sought. In all cases, the appropriate bibliographic citation and notice of the APS copyright must be included."

An Erratum to this article was published on April 27, 2022.

Original Publication Citation

BriceΓ±o, R.A., Dudek, J.J., Edwards, R.G., Shultz, C.J., Thomas, C.E. & Wilson, D.J. (2016) πœ‹πœ‹ β†’ πœ‹π›Ύ* amplitude and the resonant 𝜌 β†’ πœ‹π›Ύ* transition from lattice QCD Physical Review D. 93(11), 1-20, Article 114508.


0000-0003-1109-1473 (BriceΓ±o), 0000-0003-4327-2121 (Dudek)