C. C. Morehouse

Properties of anomalous eμ events produced in e+e− annihilation☆☆☆

Abstract We present the properties of 105 events of the form e + + e − → e +- + μ ∓ + missing energy, in which no other charged particles or photons are detected. The simplesthypothesis compatible with all the data is that these events come from the production of a pair of heavy leptons, the mass of the lepton being in the range 1.6 to 2.0 GeV/ c 2

Test of a lead/liquid argon electromagnetic shower detector☆

Abstract The design and construction of two lead/liquid argon electromagnetic shower detectors are described. Test results in beams of electrons and π − of momenta 0.125-4 GeV/ c and 1–4 GeV/ c respectively are presented. Measurements were made of the energy resolution for electromagnetic showers, the position resolution, the behavior of the device in a transverse magnetic field and the radial and longitudinal characteristics of energy deposition, especially as they apply to π − /e − discrimination.

D meson production and decay in e+e− annihilation at 4.03 and 4 GeV c.m. energy☆

Abstract Decay modes of the charmed mesons, D 0 and D + , are studied in e + e − annihilation data at 4.03 and 4.41 GeV c.m. energy. The products of cross section times branching ratio are measured for the K − π + , K − π + π + π − , K S π + π − and K − π + π + final states. Upper limits are established for the Cabibbo forbidden decays via π + π − , K + K − , K + K − π + , K + π + π − and π + π − π + . The K − π + π + π − final state is shown to be dominated by K − π + ρ 0 .

The production of ∑±'s in e+e− annihilations

We find an increase in ∑± production between Ecm = 4 and 7 GeV which is consistent with charmed baryon production models. A search for the decay ∧c−→∑±π±π− yields no significant peaks.

Recent Results for e + e − Annihilation at Spear

In this presentation I shall assume that everyone is familiar with the existence of two narrow resonances coupling to electrons1,2,3 at masses of 3.1 and 3.7 GeV. Properties of these resonances will be described at length. I shall also discuss upper limits which we can place for the production of other such resonances in the range 3.2 to 5.9 GeV.4 Lastly, I shall discuss some tantalizing structure at 4.1 GeV.5 This talk will concentrate upon the experimental facts, various speculations will be left for other speakers. It should be emphasized that most results described are preliminary and are subject to refinement.