Electromagnetic Studies of Pseudoscalar Mesons Dan Dale Idaho State University For the PrimEx Collaboration

Participating Institutions North Carolina A&T State University University of Massachusetts University of Kentucky Idaho State University Jefferson Lab Hampton University MIT University of North Carolina at Wilmington Catholic University of America Arizona State University University of Virginia ITEP, Russia IHEP, Russia Norfolk State University University of Illinois Kharkov Inst. of Physics and Technology Chinese Institute of Atomic Energy IHEP, Chinese Academy of Sciences George Washington University Yerevan Physics Institute, Armenia Southern University at New Orleans Tomsk Polytechnical University, Russia University of Sao Paulo

Leading order corrections (Donoghue, 1989)

The Primakoff Effect Radiative width Known, measured quantities

Current experimental and theoretical status

Q 2 = (m s 2 – m 2 )/(m d 2 -m u 2 )

The pion transition form factor

The eta transition form factor

In-beam calibration

Pion form factor, 11 GeV, He 4 0 < Q 2 < 0.1 GeV 2

The eta transition form factor

0 < Q 2 < 0.1 GeV 2