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From the interactions of a deuteron beam in a liquid-hydrogen target at energies near the d+p-+ 3 He + 77 threshold, r? events were selected on the basis of the momentum-analyzed 3 He with a background of less than 2%. This opens the way to a 3 He-tagged r\ beam at Saturne, with a possible flux of 10 4 -10 5 77' s per pulse. The present data allow an evaluation of the cross section down to less than 0.5 MeV above threshold. The deuteron tensor analyzing power f 20 has also been measured: The small negative value found at threshold (-0.15 ±0.05) seems incompatible with models based on one-pion exchange.

We present a measurement of the flux of neutrino-induced upgoing muons (∼ 100 GeV) using the MACRO detector. The ratio of the number of observed to expected events integrated over all zenith angles is 0.74 ±0.036(stat) ±0.046(systematic) ±0.13(theoretical). The observed zenith distribution for −1.0 ≤ cos θ ≤ −0.1 does not fit well with the no oscillation expectation, giving a maximum probability for χ 2 of 0.1%. The acceptance of the detector has been extensively studied using downgoing muons, independent analyses and Monte-Carlo simulations. The other systematic uncertainties cannot be the source of the discrepancies between the data and expectations.We have investigated whether the observed number of events and the shape of the zenith dis-1

The vertical underground muon intensity has been measured in the slant depth range 3200-7000 hg cm(-2) (standard rock) with the completed lower part of the MACRO detector at the Gran Sasso laboratory, using a large sample of data. These observations are used to compute the surface muon flux and the primary ''all-nucleon'' spectrum. An analysis of systematic uncertainties introduced by the interaction models in the atmosphere and the underground propagation of muons is presented

Using 5.33 × 106 single muons collected in 1.46 × 104 live hours by MACRO during the period 1991–1994, we have searched for a correlation between variations in the underground muon rate, Nμ, and seasonal temperature variations in the atmosphere. These correlations are found to be present with high statistical significance. Analysis of the relatively complete December 1992–December 1994 subset of the data yields a value for the temperature coefficient, . Analysis of the total data set gives consistent results.We have compared this result with the hypothesis that the muons observed in MACRO come from pion decays alone. Although our result is consistent with the ‘pion only’ hypothesis, a discussion of the sensitivity of our data sample to the kaon component of the cascades leading to observed muons underground will also be presented

We report a measurement of the negative pion electromagnetic form factor in the range of space-like four-momentum transfer 0.014 < q2 < 0.122 (GeV/c)2. The measurement was made by the NA7 collaboration at the CERN SPS, by observing the interaction of 300 GeV pions with the electrons of a liquid hydrogen target. The form factor is fitted by a pole form with a pion radius of = 0.657 +- 0.012 fm

We describe a new hadronic-interaction model for the calculation of high-energy cosmic-ray cascades in the atmosphere. High-energy muons above 0.5 TeV at production are transported through 7000 hg/cm2 of rock in order to obtain the multiplicity and lateral distributions at different depths. These distributions are parametrized to facilitate the calculation of the muon-bundle rates deep underground. As an illustration, these results are applied to calculate the rates of coincident multiple muons in a detector of finite area at the Gran Sasso Laboratory. We study in particular the sensitivity of rates of high-multiplicity events to chemical composition of the primary cosmic radiation and to uncertainties in the interaction model. Our results point to the importance of the coincident measurement of showers at the surface to maximize the power of an underground detector to study the primary composition.

Very little is known about the influence of environmental radiation on living matter. In principle, important information can be acquired by analysing possible differences between parallel biological systems, one in a reference-radiation environment (RRE) and the other in a low-radiation environment (LRE). We took advantage of the unique opportunity represented by the cell culture facilities at the Gran Sasso National Laboratories of the Istituto Nazionale di Fisica Nucleare, where environment dose rate reduction factors in the underground (LRE), with respect to the external laboratory (RRE), are as follows: 10(3) for neutrons, 10(7) for directly ionizing cosmic rays and 10 for total γ-rays. Chinese hamster V79 cells were cultured for 10 months in both RRE and LRE. At the end of this period, all the cultures were kept in RRE for another 6 months. Changes in the activities of antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPX) and spontaneous mutation frequency at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus were investigated. The results obtained suggest that environmental radiation might act as a trigger of defence mechanisms in V79 cells, specifically those in reference conditions, showing a higher degree of defence against endogenous damage as compared to cells grown in a very low-radiation environment. Our findings corroborate the hypothesis that environmental radiation contributes to the development of defence mechanisms in today living organisms/systems.