Speaker
Description
The implementation of general principles, like analyticity and unitarity, can help to constrain the determination of hadronic properties from lattice QCD (LQCD).
We present the LQCD calculation of the pion vector form factor over spacelike and timelike kinematics, with a pion mass of approximately $284$ MeV.
We go beyond the elastic timelike region, and implement for the first time the generalization of the Lellouch-Lüscher formalism for coupled channels, which in this case corresponds to the pion and kaon vector-isovector timelike form factors.
We show that the spacelike and elastic timelike regions can be described simultaneously with parameterizations satisfying analyticity and unitarity.
Subsequently, we show that our coupled-channel determination is consistent with the determination restricted to the elastic region.
This work demonstrates the capability of LQCD calculations to go beyond the determination of form factors restricted to only spacelike or only elastic timelike regions.
