πγ → ππ transition and the ρ radiative decay width from lattice QCD
Name
PhysRevD.98.074502.pdf
Size
5.37 MB
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Adobe PDF
Checksum (MD5)
25c94c7ee78e2c550ca2057094d2dcaa
Author(s)
Negele, John W.
Date Issued
October 2018
Journal
Physical review D
Publisher
American Physical Society
Citation
Alexandrou, Constantia, et al., "πγ → ππ transition and the ρ radiative decay width from lattice QCD." Physical review D 98 (October 2018): no. 074502 doi 10.1103/PhysRevD.98.074502 ©2018 Author(s)
Version
Final published version
Abstract
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 32^{3}×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[over →]|=sqrt[3]2π/L 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 q^{2} 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 |G_{ρπγ}|=0.0802(32)(20). ©2018
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Center for Theoretical Physics
Terms of Use
Creative Commons Attribution 3.0 unported license
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DOI of Published Version
https://doi.org/10.1103/PhysRevD.98.074502
