C. Mencuccini

Multihadronic cross sections from e+e− annihilation at C.M. energies between 1.4 and 2.4 GeV

Abstract Multihadronic production has been observed at the Adone e + e − storage ring, in the c.m. energy range 1.4 - 2.4 GeV. The cross sections for the reactions e + + e − → 2 π ± + nπ o (1 ⩽ n ⩽ 4) and e + + e − → (4 π ± + nπ ± ) (0 ⩽ n ⩽ 2) have been measured, assuming that the produced particles are only pions with a pure phase space momentum distribution.

Multihadronic cross sections from e+ e− annihilation up to 3 GeV c.m. energy

Abstract With an apparatus slightly improved with respect to a previous one we have studied multihadronic production at the Adone e + e − storage ring up to a maximum center of mass energy of 3 GeV.

PHOTOPRODUCTION OF THE ETA MESON ON DEUTERIUM.

Abstract The differential cross section at several c.m. angles for inelastic eta meson photoproduction on deuterium has been measured at an incident photon energy of about 850 MeV. Our results indicate that the photoproduction cross section on the neutron is quite similar to that on the proton. Both these c.m. angular distributions are consistent with isotropy. Remarks are made on the relative contribution of the isoscalar and isovector parts of the eta photoproduction amplitude.

Experimental results on a search for narrow resonances in e+e- annihilation into hadrons in the mass region 2520–2990 MeV

Abstract A search for possible new resonances produced in e + e - annihilation at Adone has been performed in the mass region 2520–2990 MeV. No evidence has been found for new resonances. We obtain an upper limit on the energy integrated resonant cross section of about 6% of the J/ψ (3100) corresponding value.

Search for narrow resonances in e+e− annihilation into hadrons in the mass regions 1910–2545 MeV and 2970–3090 MeV

Abstract We have searched for possible narrow resonances produced in e + e − annihilation at Adone, in the mass regions 1910–2545 MeV and 2970–3090 MeV. No evidence has been found for narrow resonances, within the sensitivity of the present work: we deduce an upper limit on the energy integrated resonant cross section of about 10% of the J/ψ(3100) corresponding value.

Electron-positron bremsstrahlung at ADONE. A new limit for the existence of a heavy electron

Abstract A new measurement of the cross section for the reaction e+e− → e+e− γ has been performed at the ADONE storage ring, using a wide angle electromagnetic detector together with tagging counters for detecting small-angle electrons. The results are in agreement with the QED predictons. New limits for the mass and coupling constant (e∗, eγ) of a heavy electron, e∗, have been established.

Angular distributions for single neutral pion photoproduction from neutrons at 450–800 MeV

Abstract Differential cross sections for single photoproduction of neutral pion on neutron have been measured at different c.m. angles for photon energies, between 450–800 MeV. The results are compared with the existing theories and seem to favour the hypothesis of an appreciable presence of the P 11 (1470) in the neutron photoexcitation.

Search for narrow resonances in the mass region 1.45–1.92 GeV, in e+e− annihilation into hadrons

Abstract We have searched for possible narrow resonances produced in the reaction e + e − → hadrons, at Adone, in the mass interval. 1.45–1.92 GeV. Within the present statistics, no evidence has been found. We obtain an upper limit on the energy integrated resonant cross section of about 6% of the corresponding J/ψ(3.1) value.

Wide angle electron-positron bremsstrahlung at adone a new limit for the existence of a heavy electron

Abstract The cross section for the reaction e++e−→e++e−+γ has been measured at the Adone storage ring. The results in agreement with the QED predictions, establish a new limit for the mass and the coupling constant e ∗ e γ of a heavy electron e∗.

Search for the radiative η′(958)+γ decay of the J/Ψ (3100) resonance produced in e+e− annihilation

Abstract The decay J/ Ψ (3100)→ η (958) + γ has been searched for at tthe Adone e + e +- storage ring. No candidate event has been found. This allows to set an upper limit of 1.0 keV (90% C.L.) for this decay partial width.