Mainz 2012 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 54: Hadronenstruktur und -spektroskopie

HK 54.2: Talk

Friday, March 23, 2012, 11:30–11:45, RW 1

Meson Transition Form Factors at BABAR — •Konrad Griessinger — Institut für Kernphysik, Universität Mainz, Deutschland

At electron-positron colliders like the PEP-II rings at SLAC (Stanford), meson transition form factors can be accessed through γ^(∗) γ^(∗)-processes. We present recent BABAR results for the cross sections of the γ γ^∗-fusion reaction resulting in either π⁰, η or η^′, where one of the photons is quasi-real (Q² ≈ 0). The γ γ^∗ production cross section in such a single-tag measurement is proportional to the transition form factor F(Q²). After extracting F(Q²), models to compute the contribution of the hadronic light-by-light scattering process to the standard model predicition of the muon anomaly (g_µ−2) can be tested via the transition form factor’s Q² dependence.