L. Monari

Limits of the mass of heavy leptons

SummaryA further search for heavy leptons at the ADONE e+e− storage ring has revealed no events. This establishes, with 95% confidence, that, if a heavy lepton exists and is universally coupled only to ordinary leptons, its mass must be heavier than 1.4 GeV. If it is also coupled to the hadrons, its mass must be greater than 1 GeV, again with 95% confidence.RiassuntoUn’ulteriore ricerca dei leptoni pesanti agli anelli di accumulazione e+e− ADONE, non ha rivelato alcun evento. Ciò permette di stabilire, con un livello di fiducia del 95%, che se esite un leptone pesante ed è accoppiato universalmente soltanto ai leptoni ordinari, la sua massa deve essere maggiore di 1.4 GeV. Se esso è accoppiato anche agli adroni, la sua massa deve essere maggiore di 1 GeV, al medesimo livello di fiducia del 95%.

The energy dependence of σ(e+e− → hadrons) in the total centre-of-mass energy range 1.2 to 3.0 GeV

Abstract We have observed 1085 events of the type e + e − → hadrons, in the total centre-of-mass energy range √ s = 1.2 to 3.0 GeV. The energy dependence of the total annihilation cross-section, parametrized in the form σ ( e + e − → hadrons ) = A · s n , is measured to be n = -(1.54 −0.29 +0.17 ) in the above energy range.

Cross-section measurements for the exclusive reaction e+e− → 4π± in the energy range 1.2–3.0 GeV☆

Abstract We have measured the crosss section for the reaction e + e − → 4 π ± in the energy range 1 2–3.0 GeV.No statistically significant evidence for a new vector meson in the ϱ″ region is found.

A study of the possible existence of ρ′ and ρ″

SummaryThe possible existence of new vector mesons above the ρ is investigated. The conclusion is that our data are compatible with the existence of the ρ′-meson only if we assume as a firm theoretical prediction the Gounaris-Sakurai tail of the standard ρ-meson. Furthermore our data are compatible with the existence of the ρ″-meson if we assume the validity of the

Limits on the couplings of ϱ′ (1300 Me) and rhov;″ (1700 MeV) to the photon and to the (ππ) system

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Erratum to: Direct check of QED in e+e− interaction at highq2-values

p model for the calculation of the multihadron cross-section.RiassuntoSi indaga la possibile esistenza di nuovi mesoni vettoriali con masse maggiori di quelle della ρ. Si conclude che i nostri dati sono compatibili con l’esistenza della risonanza ρ′ soltanto se si fa l’ipotesi che la coda della ρ sia descritta dalla formula di Gounaris-Sakurai. Inoltre i nostri dati sono compatibili con l’esistenza del mesone ρ″ solo se si calcola la sezione d’urto multiadronica basandosi sulla validità del modello di annichilazione antiprotone-protone.

Erratum to: A check of quantum electrodynamics and of electron-muon equivalence

Abstract The analysis of 1466 events of the type e + e − → μ ± μ ± , in the time-lifke range from 1.44 to 9.00 GeV 2 , sh that the absolute value of the cross-section and its energy dependence follow QED expectations within (± 3.2%) and (± 1.2%), respectively.

Measurements of sigma(e+e- --> mu+/-mu+/-) in the energy range 1.2-3.0 GeV

Abstract The analysis of the reaction e+e−→π+π− measured at the e+e− colliding beam machine ADONE shows that, if ϱ′ and ϱ″ exist, the cross sections compare as follows (taking the ϱ as the reference point): σ( e + e − → ϱ → π + π − ) : σ(e+e− → ϱ′ → π+π−): σ(e+e− → ϱ″ → π+π−) = 1: (7 ± 4) × 10−3: (1 ± 5) × 10−4. The square of the product of their couplings to the photon (γϱ) and the γγ system (gϱππ) are derived.