Calculating the $\rho$ radiative decay width with lattice QCD

Luka Leskovec, Constantia Alexandrou, John Negele, Stefan Meinel, Srijit Paul, Marcus Petschlies, Andrew Pochinsky, Gumaro Rendon, Sergey Syritsyn
2019 Proceedings of The 36th Annual International Symposium on Lattice Field Theory — PoS(LATTICE2018)   unpublished
We present the results of our lattice QCD study of the πγ → ππ process, where the ρ resonance appears as an enhancement in the transition amplitude. We use N f = 2 + 1 clover fermions on a lattice of L = 3.6 fm and a pion mass of 320 MeV. Using a combination of forward, stochastic, and sequential propagators, we calculate the two-point and three-point functions that allow us to determine the πγ → ππ matrix elements for several values of the invariant mass s and momentum transfer q 2 . To fit
more » ... q 2 and s dependence of the πγ → ππ amplitude, we explore a set of general parametrizations based on a Taylor expansion. By analytic continuation to the complex pole corresponding to the ρ resonance, we determine the resonant form factors and calculate the radiative decay width of the ρ.
doi:10.22323/1.334.0065 fatcat:ng2a6vzhszh6fbgcch75ryojza