A. Nigro

EVIDENCE FOR THE EXISTENCE OF A NEW VECTOR MESON OF MASS 1.82 GeV OBSERVED IN e+e- ANNIHILATIONS AT ADONE

Evidence is presented for the occurrence in e+e− annihilation of a new vector meson of mass 1821 ± 16 MeV and Γ = 31 ± 15 MeV.

Momentum analysis of kaon and pion pairs produced from time-like photons at 1.6 GeV energy

We present results for the total cross section of e+e− annihilation into two hadrons at 1.6 GeV: σππ = σKK = (1.8 ± 1.1) × 10-33 cm2.From these values we obtain the time-like electromagnetic form factors these mesons: |Fπ|2 = 0.24 ± 0.14 and |FK|2 = 0.46 ± 0.26.

Multihadron production from e+e− annihilation at 1.6 c.m. energy

The results obtained in the investigation of the multihadron production in e+e- annihilation at 1.6 GeV cm energy are presented

Multiparticle production from e+e− interactions at high energy

Abstract Measurements of multiple particle production at ADONE, the Frascati e + e − storage ring, have been carried out at C.M. energies 1.4 GeV to 2.4 GeV. The hadronic nature of the observed particles is discussed and a lower limit of 30 nbarn set for the total multiparticle cross section.

Description and performance of MEA, The magnetic detector at adone

Abstract The experimental detector at Adone, MEA, which operates with its magnetic field perpendicular to the e + e − beams is described. Studies of the magnetic compensation for operation at Adone and resulting magnetic fields are presented. Particles are detected and analyzed using narrow-gap and wide-gap spark chambers which are triggered by scintillation and proportional counters. Momentum measurements for charged particles are made with Δ / p / p = ±0.07 at p = 1 Gev/ c ( B = 2.5 kG) and angles are measured to better than ± 1.5° over a solid angle of ∼0.3 × 4 π sr.

Search for narrow resonances in e+e− annihilation into hadrons at adone in the mass region 2.5–3.0 GeV/c2

Abstract The mass region 2.5 to 3.0 GeV/ c 2 has been searched for evidence of ψ-like narrow resonance in e + e − annihilation into hadrons. No evidence for new narrow resonances has been found with a sensitivity of about the 10% of the integrated cross section of the J/ ψ (3100).

Resonant K*(892) Production in Multihadron e+e - Annihilation.

Preliminary results on resonant K*(892) production in multihadron e+e- annihilation are presented

HIGH-ENERGY ELECTRON--POSITRON ELASTIC SCATTERING.

Abstract We present the analysis of 5164 wide angle Bhabha events collected at several c.m. energies between 1.4 and 2.4 GeV using the Frascati e + −e − storage ring, ADONE. The results are in agreement with the predictions of quantum electrodynamics within the experimental errors (±10%).

Angular distribution of Μ+Μ- pairs in the reaction e+e- → Μ+Μ- at the J/ψ energy

We report new experimental results obtained at Adone by the MEA Group on the J/+(3100) decay into much pairs. The statistics has been increased by a factor ~ 3 with respect to previous data (1), and an accurate study of possible energy-dependent effects in the angular distribution has been performed. The Magnet Group experimental set up (fig. 1) is described in detail in ref. (~). The trigger for collinear events is given by the coincidence of counters (SI .S~.S3.S4) . (S~.S~ .S~.S~) and of the multiwire proportional chambers (MWPC, 2 • 2 planes of wires parMlel to the beam direction above and below the vacuum chamber). The MWPC provide a fast selection on the radial position of the source with ~ =k 5 cm acceptance. The trigger requires also a correct timing of the event with respect to the crossing of the e+e bunches and the correct