Results are presented on multihadron production by ee− annihilation from the Mark I and Mark II detectors at SPEAR. Other than the narrow resonances psi (3095) and psi' (3684), the total hadronic cross section varies between 36.5 and 6.4 nb over the center-of-mass energy range 2.6 to 7.8 GeV with complicated structure near 4.1 GeV not completely resolved by these measurements. Evidence for scaling of inclusive momentum distributions of hadrons is presented.

We have studied hadron production in ee− annihilation at 29 GeV center-of-mass energy using the PEP-4 Time Projection Chamber Detector. The inclusive cross sections and mean multiplicities for .pi./sup + -/, K/sup + -/ and (p + anti p) production have been measured using ionization energy loss to separate particle species. We find on average 10.7 +- 0.6 .pi./sup + -/, 1.35 +- 13 K/sup + -/ and 0.60 +- 0.08 (p + anti p) per multihadron event. The differential cross section is well described by a number of Monte Carlo hadronization models. In addition, we have observed correlations in rapidity space for identified pions and kaons. Short-range KK correlations provide evidence for local flavor compensation during hadronization. Long-range .pi pi. and KK correlations indicate that the initial partons carry flavor. We also observe significant long-range .pi. K correlations as a result of heavy quark decays. 85 references, 67 figures, 11 tables.

Measurements of multihadron production in ee− annihilation at center-of-mass energies between 2.6 and 7.8 GeV are presented. Aside from the narrow resonances [psi](3095) and [psi](3684), the total hadronic cross section is found to be approximately 2.7 times the cross section for the production of muon pairs at c.m. energies below 3.7 GeV and 4.3 times the muon-pair cross section at c.m. energies above 5.5 GeV. Complicated structure is found at intermediate energies. Charged-particle multiplicities and inclusive momentum distributions are presented.

The production of D mesons in ee− annihilation for the center-of-mass energy range 3.7 to 7.0 GeV was studied with the MARK I magnetic detector at SPEAR. A resonance was observed in the total cross section for hadron production in ee− annihilation at an energy just above the threshold for charm production. This resonance, which is named psi'', has a mass of 3772 +- 6 MeV/c2, a total width of 28 +- 5 MeV/c2, a partial width to electron pairs of 345 +- 85 eV/c2, and decays almost exclusively into D anti D pairs. The psi'' provides a rich source of background-free and kinematically well defined D mesons for study. From produced in the decay of the psi'' the masses of the D° and D/sup +/ mesons were determined to be 1863.3 +- 0.9 MeV/c2 and 1868.3 +- 0.9 MeV/c2 respectively. Also the branching fractions for D° decay to K−.pi./sup +/, anti K°.pi./sup +/.pi.− and K−.pi./sup +/.pi.−.pi./sup +/ were determined to be (2.2 +- 0.6)%, (4.0 +- 1.3)%, and (3.2 +- 1.1)% and the branching fractions for D/sup +/ decay to anti K°.pi./sup +/ and K−.pi./sup +/.pi./sup +/ to be (1.5 +- 0.60)% and (3.9 +- 1.0)%. The average number of kaons per D decay was found to be 0.52 +- 0.14 K°'s and 0.42 +- 0.12 K/sup +/'s. The rate for inclusive production of D mesons at center-of-mass energies above the psi'' was measured; it is found that it can account for most, if not all, of the observed increase in the total hadronic cross-section for center-of-mass energies above 4 GeV. The inclusive momentum and energy spectra for D's were measured at the highest available center-of-mass energy (7 GeV). The energy spectra are rapidly decreasing functions of energy with a slope similar to the slope of the charged pion spectrum at the same center-of-mass energy. This behavior suggests that the fragmentation function of the charmed quark into charmed mesons is a decreasing function of the scaling variable z = 2E/sub D//E/sub CM/. 81 references.