F. Felicetti

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

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

Inclusive study of hadron production by e+e− annihilation for 1.4⩽√s⩽2.3 GeV at adone

SummaryResults are reported on the inclusive study of the production of charged particles in the reaction e+e− → many hadrons in the c.m. energy range √s=(1.4 ÷ 2.3) GeV. The ratio between the kaons detected in the MEA apparatus at Adone and the corresponding total number of particles has been measured. The inclusive momentum distributions of the detected particles are given and the mean charged-particle energy and the mean observed multiplicity are evaluated.RiassuntoSi riportano i risultati di uno studio inclusivo sulla produzione di particelle cariche prodotte nella reazione e+e−→molti adroni nell’intervallo di energia del centro di massa √s=(1.4÷2.3) GeV. È stato misurato il rapporto tra il numero di K± rivelato dall’apparato MEA ed il corrispondente numero totale di particelle cariche. Si presentano le distribuzioni inclusive dei momenti delle particelle cariche rivelate per tre intervalli di √s ed inoltre — in funzione di √s — l’energia media e la molteplicità media delle particelle cariche rivelate.

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