Observation of Spin 1 F1 (1285) in the Reaction $\gamma \gamma^* \to$ Eta0 $\pi^+ \pi^-$

Author(s): Gidal, G; Boyer, J; Butler, F; Cords, D; Abrams, GS; Amidei, D; Baden, AR; Barklow, T; Boyarski, AM; Burchat, P; Burke, DL; Dorfan, JM; Feldman, GJ; Gladney, L; Gold, MS; Goldhaber, G; Golding, LJ; Haggerty, J; Hanson, G; Hayes, K; Herrup, D; Hollebeek, RJ; Innes, WR; Jaros, JA; Juricic, I; Kadyk, JA; Karlen, D; Klein, SR; Lankford, AJ; Larsen, RR; LeClaire, BW; Levi, ME; Lockyer, NS; Luth, V; Matteuzzi, C; Nelson, ME; Ong, RA; Perl, ML; Richter, B; Riles, K; Rowson, PC; Schaad, T; Schellman, H; Schmidke, WB; Sheldon, PD; Trilling, GH; de la Vaissiere C; Wood, DR; Yelton, JM; Zaiser, C | Abstract: We observe both the JPC=1++ f1(1285) and the JPC=0-+ (958) in tagged two-photon interactions and the (958) in untagged interactions. The measured Q2 dependence and decay distribution support the f1(1285) spin and parity assignment. The radiative width of the f1(1285) is measured as (M2/Q2)*=9.4±2.5±1.7 keV, on the assumption of a -pole form factor. © 1987 The American Physical Society.