W.E. Dieterle

Observation of the radiative transition ψ → γE(1420)

Abstract We have observed a radiative transition from the ψ to a state decaying into K S K ± π ∓ , with mass M = 1.44 −0.015 +0.01 GeV/ c 2 and width Γ = 0.05 −0.02 +0.03 GeV/ c 2 . We tentatively identify this state as the E(1420). Assuming that this state is an isospin singlet, we have determined the branching fraction product B(ψ → γ E ) × B( E × K K π) = (3.6 ± 1.4) × 10 −3 .

A measurement of the cross section for four-pion production in λλ collisions at spear☆

Abstract We present a measurement of the cross section for the reaction e + e − → e + e − π + π − π + π − at SPEAR. This channel is found to be large and dominated by the process γγ → ϱ 0 ϱ 0 → π + π − π + π − . The cross section, which is small just above the four-pion threshold, exhibits a large enhancement near the ϱ 0 ϱ 0 threshold.

Observations of S∗ → π+π−in ψ decay

Abstract Copious production of S ∗ decaying into π + π − is observed in ψ decay. (974 ± 4 - i 14 ± 5) MeV, consistent with the parameters extracted from couplede channel; fits to pheripheral π + π − and K + K − production experiments. The inclusive branching ratio for ψ → S ∗ + X is found to be (0.42 ± 0.08)%.

Observation of the Decay 00

The prompt photon decay psi(3095)..--> gamma pi../sup +/..pi../sup -/..pi../sup +/..pi../sup -/ has been studied with the Mark II detector at SPEAR. This channel is found to contain a ..gamma..rho/sup 0/rho/sup 0/ component with rho/sup 0/rho/sup 0/ masses concentrated between 1.4 and 2.0 GeV/c/sup 2/. The branching fraction for the psi..--> gamma..rho/sup 0/rho/sup 0/ decay with masses less than 2.0 GeV/c/sup 2/ is measured to be (1.25 +- 0.35 +- 0.40) x 10/sup -3/.The prompt photon decay (3095)+-+- has been studied with the Mark II detector at SPEAR. This channel is found to contain a 00 component with 00 masses concentrated between 1.4 and 2.0 GeV/c2. The branching fraction for the 00 decay with masses less than 2.0 GeV/c2 is measured to be (1.25±0.35±0.40)×10-3.

A study of the decayτ−→π−μτ

We present a high statistics measurement of the branching ratio for the decay τ-→π-μτ using data obtained with the Mark II detector at the SLAC e+e- storage ring SPEAR. We have used events from the center-of-mass energy region 3.52 to 6.7 GeV to determine that B(τ-→π-μτ)=0.117±0.004±0.018. From electron-muon events in the same data sample, we have determined that B(τ-→π-μτ) B(τ-→e--μeμτ)=0.66±0.03±0.11. We present measurements of the mass and spin of the τ and the mass of the τ neutrino based, for the first time, on a hadronic decay mode of the τ.

A search for stable particles heavier than the proton and for q = 2/3 quarks produced in e+ e- annihilation

Abstract We have searched 1.4 × 10 6 e + e − annihilation events for particles with 1–3 GeV/ c 2 mass and charge Q = − 2 3 from the processes e + e − →q q X and e + e − → q q . Upper limits of RQ ∼ 10 −4 for each process are presented which improve the previous limits on free quark production in electromagnetic interactions by 2 orders of magnitude.

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

Results on two-photon interactions from Mark II at SPEAR

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

Observation of charmed-baryon production in e+e- annihilation

s at energies Ecru > 15 GeV. In the inclusive

Measurement of the radiative width of the in two-photon interaction at SPEAR

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