Measurement of the neutral pion transition form factor at low Q² at Jefferson Lab

The neutral pion transition form factor (TFF) plays an important role in tests of low energy QCD, and in the determination of the hadronic-light-by-light (HLbL) scattering contribution to the muon anomalous magnetic moment, (g-2). Several measurements of this form factor exist in the large space-like Q² region, but the low Q² space-like region remains largely unexplored.

This talk will present the details and impact of a proposed precision measurement of the TFF to be carried out in Hall B of Jefferson Lab. This experiment will use a 10.5 GeV electron beam, silicon target and a low background beamline in Hall B to measure the virtual Primakoff cross section for neutral pion electro-production. These data will be used to extract the pion TFF in the Q² range of 0.001‑0.1 GeV², and constrain calculations for the HLbL contribution to muon (g-2) at low Q².