William Chinowsky

Meson exchange in the reaction K+ + p → K∗ + N∗

The four-particle final states of the K/sup +/-p interaction at 1.96 Bev/ c were investigated. It is found that these states are predominantly produced via the double resonance production K/sup +/ + p yields K/sup */ + N/sup */. The experimental data support a spin-zero meson exchange, presumably a meson( pi ), for small four-momentum transfers. The four particles produced in the reaction are in the isotopic spin T = 1 state and occur in five possible charge combinations. The observed cross sections of these reactions and the branching ratios expected on the assumption that the nucleon and meson( pi ) are always produced in the T = 3/2 state and that the meson (K) and ( pi ) are always produced in the T = 1/2 state are presented. (C.E.S.)

Limits on and ϒ production in e+e− interactions at

A search has been made for the inclusive production of Jψ (3.1) and ϒ (9.4) mesons in e+e− interactions at 29 GeV, via their decay into two leptons. No signal is observed in the Jψ region, nor in the ϒ region. The limits on the cross sections are σ(e+e− → ψX) < 4.4 × 10−36cm2, and σ(e+e− → ϒX) < 4.7 × 10−36 cm2. The same data yield limits on the branching ratios for the b quark BR (b → ψX) < 4.9% and BR (b → l+l−X) < 0.8%.Volume 129, number 1,2 PHYSICS LETTERS 15 September 1983 LIMITS ON J / ~ A N D T PRODUCTION IN e+e - INTERACTIONS AT X/s= 29 GeV ~ C. MATTEUZZI, G.S. ABRAMS, D. AMIDEI, C.A. BLOCKER, A.M. BOYARSKI, M. BREIDENBACH, D.L. BURKE, W. CHINOWSKY, W.E. D1ETERLE 1, J.B. DILLON, J.M. DORFAN, M.W. EATON, G.J. FELDMAN, M.E.B. FRANKLIN, G. GIDAL, L. GLADNEY, M.S. GOLD, G. GOLDHABER, L.J. GOLDING, G. HANSON, R.J. HOLLEBEEK, W.R. INNES, J.A. JAROS, A.D. JOHNSON, J.A. KADYK, A.J. LANKFORD, R.R. LARSEN, B. LeCLAIRE, M. LEVI, N. LOCKYER, V. LI]TH, M.E. NELSON, J.F. PATRICK 2, M.L. PERL, B. RICHTER, P.C. ROWSON, T. SCHAAD, H. SCHELLMAN, D. SCHLATTER, R.F. SCHWITTERS, P.D. SHELDON, J. STRAIT 3, G.H. TRILLING, C. de la VAISSIERE, J.M. YELTON and C. ZAISER Stanford Linear Accelerator Center, Stanford UniversiO,, Stanford, CA 94305, USA Lawrence Berkeley Laboratory and Department o f Physies, University of California, Berkeley. CA 94720, USA Department o f Physics, Harvard University, Cambridge, MA 02138, USA Received 29 April 1983 A search has been made for the inclusive production of J/¢, (3.1) and T (9.4) mesons in e+e - interactions at 29 GeV, via their decay into two leptons. No signal is observed in the J/O region, nor in the r region. The limits on the cross sec- tions are o (e+e - ~ ~X) 15 GeV. Very high statistics experiments are needed in order to check these calculations and to identify the differ- ent mechanisms which are involved. The perturbative calculations are however the minimal expected con- tribution to

Measurement of

inclusive production: a large uncer- tainty comes from possible non-perturbative contribu- tions. Some calculations [3] predict a cross section larger than 10 -1 ouu , which would imply a large prob- ability to observe

\gamma \gamma \psi

s at energies Ecru > 15 GeV. In the inclusive

Final States in

production e+e - -+ SX, the ~ leptonic

\psi^-

The decay mode psi ..-->.. ..gamma gamma..psi has been studied with the Mark-II detector at SPEAR. New measurements of branching ratios for decays of the type psi ..-->.. ..gamma..chi, chi ..-->.. ..gamma..psi involving known chi states are presented. The existence of a chi state of mass near 3455 MeV/c/sup 2/ produced in this decay chain is not confirmed, and the upper limit (90% confidence level) of the product of branching ratios is measured to be 0.13%. A new decay mode, psi ..-->.. ..pi../sup 0/psi, which violates isospin conservation is observed with branching ratio (0.15 +- 0.06)%.