D. Coffman

Measurement of the inclusive decay properties of charmed mesons

Abstract We report a high statistics study of the inclusive decay properties of the charmed D0 and D+ mesons, and the first inclusive study of the charmed Ds+. The data are collected at s =3.77 GeV and s =4.14 GeV with the Mark III detector at the e+e− storage ring SPEAR. For each charmed meson species, the charged-particle multiplicity, the strangeness content of the final state, and the average π0 multiplicity are determined.

The Mark III spectrometer

Abstract This paper describes the design, construction and performance of the Mark III, a new general purpose large solid angle spectrometer at SPEAR, the SLAC 2–8 GeV e+e− storage ring. The detector has been designed for the study of exclusive final states in e+e− annihilation, which requires large solid angle coverage combined with charged particle momentum resolution, particle identification, and photon detection efficiency at low energies.

Observation of f1(1285)→π+π−π+π− in radiative decays ☆

Abstract We present an analysis of J ψ →γf 1 (1285) , f 1 (1285)→ π + π − π + π − , using the Mark III detector at SPEAR, based on 5.8 × 10 6 produced J ψ events. We measure B( J ψ →γf 1 (1285) , f 1 (1285)→ π + π − π + π − )=(4.8±1.3±0.9) × 10 −5 . We obtain a new measurement of the absolute branching ratio of J ψ →γf 1 (1285) . The mixing angle of the f 1 (1285) and the f 1 (1420) in the 1 ++ nonet is determined.

Recent Ψ′ results from Mark III☆

This paper presents recent results from the Mark III detector at SPEAR, in the open charm sector. The first topic discussed is the reanalysis of the direct measurement of the D hadronic branching fractions, where a detailed study has been made of the Cabibbo suppressed and multi-..pi../sup 0/s D decays backgrounds in the double tag sample. Next, the Dalitz plot analysis of the D decays to K..pi pi.. is presented, leading to the relative fractions of three-body versus pseudoscalarvector decays. 7 refs., 5 figs.

Search for the decay D0K0e+e-

A search for the decay of the charmed meson /ital D//sup 0//r arrow//bar K//sup 0/e/sup +/e/sup /minus// is presented, based on data collected at the /psi/(3770) resonance with the Mark III detector at the SLAC storage ring SPEAR. No evidence for this process is found, resulting in an upper limit on the decay branching ratio of 1.7/times/10/sup /minus/3/ at the 90% confidence level.