Dispersive analysis of the pion transition form factor

作者：Hoferichter M^*; Kubis B; Leupold S; Niecknig F; Schneider S P

来源：European Physical Journal C, 2014, 74(11): 3180.

DOI：10.1140/epjc/s10052-014-3180-0

We analyze the pion transition form factor using dispersion theory. We calculate the singly-virtual form factor in the time-like region based on data for the e(+) e(-) -%26gt; 3 pi cross section, generalizing previous studies on omega, phi -%26gt; 3 pi decays and gamma pi -%26gt; pi pi scattering, and verify our result by comparing to e(+) e(-) -%26gt; pi(0)gamma. data. We perform the analytic continuation to the space-like region, predicting the poorly-constrained space-like transition form factor below 1GeV, and extract the slope of the form factor at vanishing momentum transfer a(pi) = (30.7 +/- 0.6) x10(-3). We derive the dispersive formalism necessary for the extension of these results to the doubly-virtual case, as required for the pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon.

• 出版日期2014-11-27