Search for Slowly Moving Magnetic Monopoles with the MACRO Detector

A search for slowly moving magnetic monopoles in the cosmic radiation was conducted from October 1989 to November 1991 using the large liquid scintillator detector subsystem of the first supermodule of the MACRO detector at the Gran Sasso underground laboratory. The absence of candidates established an upper limit on the monopole flux of 5.6 × 10^(−15) cm^(−2) sr^(−1) s^(−1) at 90% confidence level in the velocity range of 10^(−4)≲β<4×10^(−3). This result places a new constraint on the abundance of monopoles trapped in our solar system

New MACRO results on atmospheric neutrino oscillations

The final results of the MACRO experiment on atmospheric neutrino oscillations are presented and discussed. The data concern different event topologies with average neutrino energies of ~3 and ~50 GeV. Multiple Coulomb Scattering of the high energy muons in absorbers was used to estimate the neutrino energy of each event. The angular distributions, the L/E_nu distribution, the particle ratios and the absolute fluxes all favour nu_mu --> nu_tau oscillations with maximal mixing and Delta m^2 =0.0023 eV^2. A discussion is made on the Monte Carlos used for the atmospheric neutrino flux. Some results on neutrino astrophysics are also briefly discussed.Comment: Invited Paper at the NANP03 Int. Conf., Dubna, 200

SEARCH FOR SLOWLY MOVING MAGNETIC MONOPOLES WITH THE MACRO DETECTOR

A search for slowly moving magnetic monopoles in the cosmic radiation was conducted from October 1989 to November 1991 using the large liquid scintillator detector subsystem of the first supermodule of the MACRO detector at the Gran Sasso underground laboratory. The absence of candidates established an upper limit on the monopole flux of 5.6 x 10(-15) cm-2 sr-1 s-1 at 90% confidence level in the velocity range of 10(-4) less than or similar to beta < 4 x 10(-3). This result places a new constraint on the abundance of monopoles trapped in our solar system

Search for neutrinos from the Sun and the Earth with the MACRO detector

Upward-going muon events collected with the lower half of the MACRO detector have been analyzed in order to search for Weakly Interacting Massive Particles possibly trapped in the core of the Sun and of the Earth. No statistically significant signal could be discriminated over the possible fluctuations of the atmospheric neutrino background. Assuming a particular neutralino model, the explorable neutralino mass region has been considered

Study of primary interactions with multiple muons in MACRO

The MACRO underground experiment has started a systematic experimental study of the structure of a very high multiplicity event sample, with the aim of gaining a better understanding of the features of the high energy showers. We present here two new analyses: a) the analysis of the distribution of the separation between pairs of high multiplicity muons (''decoherence'' function); b) the search for clusters of muons within high multiplicity events. The first results are discussed together with a comparison between the real data and the Monte Carlo predictions