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.).

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.

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Charged-particle multiplicity distributions in 300-GeV/c pd interactions have been determined from an exposure of the Fermi National Accelerator Laboratory 30-in. bubble chamber. The data show clear evidence for double scattering inside the deuterium nucleus. We have been able to correct for the effects of the second scatters using a simple semiempirical model. The resulting pp multiplicity distribution is in excellent agreement with the pp data obtained from a p-H, experiment at the same energy. The pn multiplicity distribution appears to be shifted from the pp distribution with (n,),, = 7.84+0.17.

The Crystal Ball detector at SPEAR has been used to investigate the decays '#'+YYJ/9,J/J~(ete-or b+v') resulting from production of 8x105 .#f. From this selection of the data we measure the branching ratios for the processes q'-'(7) or T~)J/$ and.$'+yx,x-+yJ/+. An analysis of the angular correlations in the latter process furnishes measurements of the x(3.55) and x(3.51) spins and of the multipole structure of the radiative transitions.