The LVD experiment at Gran Sasso |
| |
Authors: | M Aglietta P Antonioli G Badino M Bertaina R Bertoni A Castellina A Chiavassa W Fulgione P Galeotti P Ghia A Giuliano R Granella C Melagrana C Morello G Navarra L Panaro L Periale P Picchi O Saavedra G C Trinchero P Vallania S Vernetto and C Vigorito |
| |
Institution: | (1) Istituto di Fisica dell'Università e Sezione INFN, Torino, Italy;(2) Istituto di Cosmogeofisica del CNR, Torino, Italy |
| |
Abstract: | Summary The Large-Volume Detector (LVD) in the Gran Sasso underground Laboratory is a multipurpose detector consisting of a large
volume of liquid scintillator (at present 562 tons are in data taking) interleaved with limited-streamer tubes. Several physical
problems are investigated with LVD, the major being the search for neutrino bursts from gravitational stellar collapses in
our Galaxy. In this paper we discuss some results on cosmic neutrinos and cosmic-ray muons obtained with the first of the
five towers of LVD (operational since June 1992) and part of the second tower (operational since June 1994). The results of
the search for supernovae neutrinos show that LVD is a neutrino observatory able to detect neutrinos of different flavours
from gravitational stellar collapses in all our Galaxy, over a wide range of burst durations. Indeed, the carbon-based liquid-scintillator
target gives a unique possibility to directly detect neutral- and charged-currents neutrino interactions with a very good
signature. This characteristic of LVD allows us to make an indirect estimate of the neutrino rest mass and of neutrino oscillations
from supernovae in our Galaxy. No evidence for burst candidates has been found in the data recorded from June 1992 to March
1995, for a total live time of 682 days and a total exposure of 613 tons per year. We present the results of a time coincidence
analysis between low-energy signals, eventually due to neutrinos of different flavours, and γ-ray bursts (GRBs) detected by
the BATSE experiment. This search covers the period from June 1993 to March 1995, during which 41 GRBs have been selected
from the BATSE data. Since no excess of events in LVD has been found, upper limits on the neutrino fluxes are reported for
(νe, p), and for neutral- and charged-currents neutrino interactions of different flavours with the C-nuclei of the scintillator.
The muon intensity as a function of slant depth is presented. These measurements, obtained during a live time period of 11.556
hours, cover a slant depths range from about 3000 to about 20 000 hg/cm2 of standard rock and extend over five decades of intensity. An interesting result is that the muon flux is independent of
slant depth beyond a depth of about 14 000 hg/cm2 of standard rock, and corresponds to near horizontal muons. This is direct evidence that this flux is due to atmospheric
neutrinos interacting in the rock surrounding LVD. |
| |
Keywords: | Cosmic-ray interactions with the Earth |
本文献已被 SpringerLink 等数据库收录! |
|