Neutrino-induced and atmospheric single-muon fluxes measured over five decades of intensity by LVD at Gran Sasso laboratory

We report data taken by the LVD Experiment during a live-time period of 11 556 h. We have measured the muon intensity at slant depths of standard rock from about 3000 hg/cm(2) to about 20 000 hg/cm(2). This is an exclusive study, namely our data include only events containing single muons. This interval of slant depth extends into the region where the dominant source of underground muons seen by LVD is the interaction of atmospheric neutrinos with the rock surrounding LVD. The interesting result is that this flux is independent of slant depth beyond a slant depth of about 14 000 hg/cm(2) of standard rock. Due to the unique topology of the Gran Sasso Laboratory the muons beyond about 14 000 hg/cm(2) of standard rock are al a zenithal angle near 90 degrees. Hence we have, for this fixed angle, a muon flux which is independent of slant depth. This is direct evidence that this flux is due to atmospheric neutrinos interacting in the rock surrounding LVD. The value of this flux near 90 degrees is (8.3 +/- 2.6) x 10(-13) cm(-2) s(-1) sr(-1), which is the first reported measurement at a zenithal angle near 90 degrees and for slant depths between 14 000 and 20 000 hg/cm(2). Our data cover over five decades of vertical intensity, and can be fit with just three parameters over the full range of our experiment. This is the first time a single experiment reports the parameters of a fit made to the vertical intensity over such a large range of standard rock slant depth. The results are compared with a Monte Carlo simulation which has as one of the two free parameters gamma(pi k) the power index of the differential energy spectrum of the pions and kaons in the atmosphere. This comparison yields a value of 2.75 +/- 0.03 for gamma(pi k), where the error includes the systematic uncertainties. Our data are compared to other measurements made in our slant depth interval. We also report the value of the muon flux in Gran Sasso at theta = 90 degrees as a function of the azimuthal angle

Multiple muon events observed in the LVD experiment

This is a progress report on the multiple muon events recorded by the first tower of the LVD detector at the Gran Sasso Laboratory. About 17,000 multiple muon events have been observed since the LVD first tower started operation in June 1992. Presented here are the measured multiplicity distribution and separation distribution of muon pairs in the bundles. © 1994

SINGLE MUONS IN THE LARGE-VOLUME DETECTOR

The first angular distribution data from 5547 hours of operation of the LVD detector are presented. A total of 452,630 single muons were reconstructed for this period. We present, for the first time from Gran Sasso Laboratory, data at near-horizontal zenith angles.3524024

MULTIPLE MUON EVENTS OBSERVED IN THE LVD EXPERIMENT

This is a progress report on the multiple muon events recorded by the first tower of the LVD detector at the Gran Sasso Laboratory. About 17,000 multiple muon events have been observed since the LVD first tower started operation in June 1992. Presented here are the measured multiplicity distribution and separation distribution of muon pairs in the bundles.3524324

SEARCH FOR NEUTRINOS FROM COLLAPSING STARS WITH THE LVD AT GRAN-SASSO

The Large Volume Detector (LVD) in the Gran Sasso underground Laboratory is a multipurpose detector consisting of a large volume of liquid scintillator interleaved with limited streamer tubes. In this paper we discuss its power to study low energy cosmic neutrinos. The results show that the first of the five LVD towers, operational since June 1992 with 368 tons of liquid scintillator, is well suited to detect neutrinos from collapsing stars within all our Galaxy, over a wide range of burst duration (up to a few hundreds seconds). One year data, collected since June 1992, have been analized and results are here discussed. No evidence for burst candidates has been found in this period of data taking.3526726