%0 Journal Article
%T Decay amplitudes to three hadrons from finite-volume matrix elements
%A Hansen, M. T.
%A Romero-Lopez, F.
%A Sharpe, S. R.
%J Journal of High Energy Physics
%D 2021
%V 04
%N 4
%I Springer
%@ 1029-8479
%G English
%F Hansen_etal2021
%O WOS:000640574400001
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=4789), last updated on Mon, 03 May 2021 07:57:59 +0000
%X We derive relations between finite-volume matrix elements and infinite-volume decay amplitudes, for processes with three spinless, degenerate and either identical or non-identical particles in the final state. This generalizes the Lellouch-Luscher relation for two-particle decays and provides a strategy for extracting three-hadron decay amplitudes using lattice QCD. Unlike for two particles, even in the simplest approximation, one must solve integral equations to obtain the physical decay amplitude, a consequence of the nontrivial finite-state interactions. We first derive the result in a simplified theory with three identical particles, and then present the generalizations needed to study phenomenologically relevant three-pion decays. The specific processes we discuss are the CP-violating K -> 3 pi weak decay, the isospin-breaking eta -> 3 pi QCD transition, and the electromagnetic gamma (*) -> 3 pi amplitudes that enter the calculation of the hadronic vacuum polarization contribution to muonic g – 2.
%K Lattice QCD
%K Kaon Physics
%R 10.1007/JHEP04(2021)113
%U https://arxiv.org/abs/2101.10246
%U https://doi.org/10.1007/JHEP04(2021)113
%P 113-44pp