No abstract

200 400 600 800 EFFECTIVE MASS (MeV) 1000FIGo 2. Histogram of the effective mass distribution of the two pions from the reaction p+p-*p+p + ir + + TT~0 The solid curve is the phase-space distribution normalized to the same total area. same spin and parity, and if the £ resonance does not exist, electromagnetic mixing could lead to an order of magnitude higher rate for (a) and (b) than for the usual oo -ir + + -n" + TT° (C). On the other hand, Gell-Mann et_aL 8 calculate the decay mode ratio a/c to be only ~5%.To search for the mode co ^7r + + 7r", we have plotted in Fig. 2 the effective mass m * of the 7r + 77" combination from 683 events of the type £+£-•/>+/> +7T++ 77~. The co decay should appear as a peak at -770 MeV, within the broad band (700-800 MeV) of the p° decay. Neither the twoir decay of the u> nor any sign of the expected p°-*7T + + 77~ is observed. The absence of the p° can possibly be explained by the fact that it has a cross section comparable to the co, and this small number of events, spread over the broad effective-mass range of the p°, would not be observed. Considering the strength of the §, § up isobar, and the possibility of final state interactions, it is not surprising that multiple-pion resonances appear to have small cross sections when there are two nucleons present.A detailed investigation of the energy dependence of the K + -proton scattering cross section at low momenta has been carried out. In the region from 140 to 642 MeV/c, the nuclear cross section varies little with energy. The cross sections are distinctlv lower than values quoted earlier. 1 The momentum dependence of the phase shifts below 300 MeV/ c can only be interpreted as s-wave scattering and does not admit isotropic £-wave solutions such as were obtained as possible ambiguities at 810 MeV/ c. 2 The isotropy in the differential cross sections and the constructive interference with Coulomb scattering at each of the momenta show that the repulsive s-wave character of the K + -p T = l state persists throughout this region.An s-wave effective-range fit to the experimental 135

of the plane of polarization. The interaction, which has been observed from currents of a few amperes up to large currents, is also being studied for the onset of the conversion from damped Alfven waves to propagating helicons.

No abstract

No abstract