E. Iarocci

Experimental Study of Atmospheric Neutrino Flux in the NUSEX Experiment

The fully contained events detected in the NUSEX nucleon stability experiment have been analysed to search for possible anomalies in the fluxes of atmospheric neutrinos. The measured flux of muon neutrinos is in very good agreement with predictions and no anomaly has been found in the ratio between the rate of electron and muon neutrino events.

TOTAL CROSS-SECTION FOR HADRONIC PRODUCTION BY E+E- ANNIHILATION IN THE TOTAL CM ENERGY-RANGE 1.42-3.09 GEV

Abstract We report experimental results on the cross section for the reaction e + e − → hadrons as a function of the total c.m. energy in the range W = 1.42–3.09 GeV. The results, combined with those already existing below the charm threshold, clearly indicate a structure for R ( W ) = α ( e + e − → hadrons)/ α ( e + e − → μ + μ − ) in that energy region.

Observation of a time modulated muon flux in the direction of Cygnus X-3

Abstract The analysis of angular and phase distribution is reported for high energy muons recorded in the NUSEX nucleon decay detector, located in the Mont Blanc tunnel at a depth of about 5000 hg of standard rock. Evidence is found for a signal correlated to the direction and time modulation of Cygnus X-3.

The NUSEX detector

Abstract We present in this paper the characteristics, trigger system and performance of the NUSEX detector, designed to study nucleon stability, running in the Mt. Blanc laboratory.

Nucleon stability, magnetic monopoles and atmospheric neutrinos in the Mont-Blanc experiment

Abstract Ten totally confined events have been found in the Mont-Blanc Nucleon Stability Experiment. While nine can be interpreted as interactions of atmospheric neutrinos, one could be a proton decay. Limits are given for nucleon stability, n- n oscillations, magnetic monopoles and monopole catalysis of nucleon decay.

Measurement of hadronic exclusive cross sections in e+e− annihilation from 1.42 to 2.20 GeV

Abstract Total cross sections for reactions e+e−→π+π−π0, π+π−π0, 2π+2π−π0, 2π+2π−2π0, 3π+3π− have been measured in the total c.m. energy range 1.42–2.20 GeV. Partial R=σhad/σσ+μ− values for two and four produced charged pions, and cross sections for positive and negative G-parity states are also reported.

Measurement of the e+e-→π+π-π+π- cross section in the ϱ′(1600) energy region

Abstract The cross section for the reaction e + e - →π + π - π + π - has been measured at the e + e - storage ring Adone, in the to tal c.m. energy range 1.42–2.20 GeV. The peak and the following descent of the ϱ′(1600) resonance is observed. Using also lower energy data, and assuming that only one resonant amplitude contributes to the observed cross section, the parameters of the ϱ′(1600) are deduced.

Primary cosmic-ray spectrum at energies ∼(1013÷1016) eV from multiple muon events in NUSEX experiment

SummaryThe multiple-muon rates measured in the NUSEX experiment at a vertical depth of 5000 hg/cm2 s.r. are compared with some current models of the primary cosmic-ray composition. Monte Carlo simulations as well as analytical formulae which take into account the geometrical and acceptance features of the apparatus have been used in calculations. A good agreement is found with a model in which the relative fraction of primary heavy nuclei does not increase significantly up to about 1016 eV. This model reproduces very well both the all-nucleon flux measured in the range (1013÷1014) eV and the all-particle spectrum up to 1016 eV.RiassuntoLe frequenze di muoni multipli ottenute con il rivelatore NUSEX ad una profondità verticale di 5000 hg/cm2 sono confrontate con diversi modelli sulla composizione di primari cosmici. Questo studio è fatto usando Montecarlo e formule analitiche che tengono conto degli aspetti geometrici e dellaccettanza dellapparato. Un buon accordo è trovato con un modello nel quale la relativa frazione di nuclei pesanti non cresce significatamente fino a 1016 eV. Questo modello riproduce bene sia il flusso totale di nuclei misurato nellintervallo (1013÷1014) eV che lo spettro di particelle fino a 1016 eV.РезюмеИнтенсивности множественных мюонных событий, измеренных в NUSEX эксперименте на глубине 5000 hg/cm2 s.r., сравниваются с имеющимися моделями первичного состава космических лучей. При вычислениях используются моделирования по методу Монте-Карло и аналитические формулы, которые учитывают геометрические характеристики аппаратуры. Получается хорошее согласие с моделью, в которой относительная доля первичных, тяжелых ядер существенно не увеличивается вплоть до энергий 1016 эВ. Эта модель очень хорошо воспроизводит поток всех нуклонов, измеренных в области (1013÷1014) эВ, и спектр всех частиц вплоть до 1016 эВ.

Evidence for a resonant behaviour in e+e− annihilation into hadrons, around 1820 MeV, at adone

Abstract Multihadron production has been measured at the Adone e+e− storage ring in the c.m. energy region 1600 ÷ 1900 MeV. A resonant behaviour is observed, centered at 1819 ± 5 (±2) MeV, with a width of 24 ± 5 (±4) MeV. This effect is observed only in the events with 3 or 4 charged particles together with photons, but not in those without photons.

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.