TY - JOUR
T1 - πγ →ππ transition and the ρ radiative decay width from lattice QCD
AU - Alexandrou, Constantia
AU - Leskovec, Luka
AU - Meinel, Stefan
AU - Negele, John
AU - Paul, Srijit
AU - Petschlies, Marcus
AU - Pochinsky, Andrew
AU - Rendon, Gumaro
AU - Syritsyn, Sergey
N1 - Publisher Copyright:
© 2018 authors. Published by the American Physical Society.
PY - 2018/10/1
Y1 - 2018/10/1
N2 - We report a lattice QCD determination of the πγ→ππ transition amplitude for the P-wave, I=1 two-pion final state, as a function of the photon virtuality and ππ invariant mass. The calculation was performed with 2+1 flavors of clover fermions at a pion mass of approximately 320 MeV, on a 323×96 lattice with L≈3.6 fm. We construct the necessary correlation functions using a combination of smeared forward, sequential and stochastic propagators, and determine the finite-volume matrix elements for all ππ momenta up to |P→|=32πL and all associated irreducible representations. In the mapping of the finite-volume to infinite-volume matrix elements using the Lellouch-Lüscher factor, we consider two different parametrizations of the ππ scattering phase shift. We fit the q2 and s dependence of the infinite-volume transition amplitude in a model-independent way using series expansions, and compare multiple different truncations of this series. Through analytic continuation to the ρ resonance pole, we also determine the πγ→ρ resonant transition form factor and the ρ meson photocoupling, and obtain |Gρπγ|=0.0802(32)(20).
AB - We report a lattice QCD determination of the πγ→ππ transition amplitude for the P-wave, I=1 two-pion final state, as a function of the photon virtuality and ππ invariant mass. The calculation was performed with 2+1 flavors of clover fermions at a pion mass of approximately 320 MeV, on a 323×96 lattice with L≈3.6 fm. We construct the necessary correlation functions using a combination of smeared forward, sequential and stochastic propagators, and determine the finite-volume matrix elements for all ππ momenta up to |P→|=32πL and all associated irreducible representations. In the mapping of the finite-volume to infinite-volume matrix elements using the Lellouch-Lüscher factor, we consider two different parametrizations of the ππ scattering phase shift. We fit the q2 and s dependence of the infinite-volume transition amplitude in a model-independent way using series expansions, and compare multiple different truncations of this series. Through analytic continuation to the ρ resonance pole, we also determine the πγ→ρ resonant transition form factor and the ρ meson photocoupling, and obtain |Gρπγ|=0.0802(32)(20).
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U2 - 10.1103/PhysRevD.98.074502
DO - 10.1103/PhysRevD.98.074502
M3 - Article
AN - SCOPUS:85056178910
SN - 2470-0010
VL - 98
JO - Physical Review D
JF - Physical Review D
IS - 7
M1 - 074502
ER -