A new measurement of the elastic scattering of 250-GeV/e negative pions by electrons provides form-factor results from 0.0368&q~& 0.0940 (Gev/c)2. These measurements determine the mean square pion radius to be (r~~) = 0.439 + 0.030 fm' or (r~~) 'I~= 0.663 + 0.023 fm. Comparisons are made with previous elastic-scattering experiments as well as with results obtained from electroproduction experiments, e e annihilation experiments, and phenomenological analyses.

The reaction e+e~e+e m. m has been analyzed using 97 pb ' of data taken with the Crystal Ball detector at the DESY e e+ storage ring DORIS II at beam energies around 5.3 GeV. For the first time we have measured the cross section for yy~m. m. for n m invariant masses ranging from threshold to about 2 GeV. We measure an approximately flat cross section of about 10 nb for 8'=m 0 0 (0.8 GeV, which is below 0.6 GeV, in good agreement with a theoretical prediction 'tr n' based on an unitarized Born-term model. At higher invariant masses we observe formation of the ft(1270) resonance and a hint of the fo(975). We deduce the following two-photon widths: I rr(f, (1270)) =3.19+0. 1620 z, keV and I "(fo( 975)) (0.53 keV at 90% CL. The decayangular distributions show the m~system to be dominantly spin 0 for W &0.7 GeV and spin 2, helicity 2 in the f, (1270) region, with helicity 0 contributing at most 22% (90% C.L.).

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Results from a detailed study using the Crystal Ball detector at the SLAC e+e storage ring SPEAR of the inclusive photon spectra from 1.8 X 106 i(t' and 2.2&& 106 J/P decays are presented. Radiative transitions from the P to the 1'2~o states are observed with photon energies of 126.0+0.2+4, 169.6+0.3 +4, and 258.4+0.4+4 Mev and branching ratios 8(i('~y X2, &, p) =(8.0%0.5+0.7)%, (9.0+0.5+0.7)%, and (9.9+0.5+0.8)%, respectively. Values for the natural linew'idths of the p states are obtained: I (p2 l 0)=0.8-4.9, &3.8, and 13-21 MeV, respectively (90% C.L.). Improved values are found for the branchmg ratios 8(g'~yg,) =(0.28+0.06)% and B(J//~yes,) =(1.27+0.36)%, and for the natural width I (g,) =11.524.5 MeV.