Study of single muons with the Large Volume Detector at Gran Sasso Laboratory

The present study is based on the sample of about 3 mln single muons observed by LVD at underground Gran Sasso Laboratory during 36500 live hours from June 1992 to February 1998. We have measured the muon intensity at slant depths from 3 km w.e. to 20 km w.e. Most events are high energy downward muons produced by meson decay in the atmosphere. The analysis of these muons has revealed the power index of pion and kaon spectrum: 2.76 \pm 0.05. The reminders are horizontal muons produced by the neutrino interactions in the rock surrounding LVD. The value of this flux is obtained. The results are compared with Monte Carlo simulations and the world data.Comment: 13 pages, 2 figures, accepted for publication in "Physics of Atomic Nuclei

Upper Limit on the Prompt Muon Flux Derived from the LVD Underground Experiment

We present the analysis of the muon events with all muon multiplicities collected during 21804 hours of operation of the first LVD tower. The measured depth-angular distribution of muon intensities has been used to obtain the normalization factor, A, the power index, gamma, of the primary all-nucleon spectrum and the ratio, R_c, of prompt muon flux to that of pi-mesons - the main parameters which determine the spectrum of cosmic ray muons at the sea level. The value of gamma = 2.77 +/- 0.05 (68% C.L.) and R_c < 2.0 x 10^-3 (95% C.L.) have been obtained. The upper limit to the prompt muon flux favours the models of charm production based on QGSM and the dual parton model.Comment: 10 pages, 4 figures, RevTex. To appear in Phys. Rev.

Muon `Depth -- Intensity' Relation Measured by LVD Underground Experiment and Cosmic-Ray Muon Spectrum at Sea Level

We present the analysis of the muon events with all muon multiplicities collected during 21804 hours of operation of the first LVD tower. The measured angular distribution of muon intensity has been converted to the `depth -- vertical intensity' relation in the depth range from 3 to 12 km w.e.. The analysis of this relation allowed to derive the power index, $\gamma$, of the primary all-nucleon spectrum: $\gamma=2.78 \pm 0.05$. The `depth -- vertical intensity' relation has been converted to standard rock and the comparison with the data of other experiments has been done. We present also the derived vertical muon spectrum at sea level.Comment: 7 pages, 3 figures, to be published on Phys. Rev.

Multiple Correlations and High Tranverse Momentum Jets in 147-GeV/c pi- p Interactions

We examine multiparticle correlations in a {pi}{sup -}p experiment at 147 GeV/c performed by the Proportional Hybrid System Consortium. The major aim of this paper is to demonstrate the existence of clusters in our data. We use different statistical algorithms to assemble into clusters the particles in each event which are associated by virtue of small relative angles. We find that these clusters are stable against different choices of metric and/or algorithm, and reproduce the effects previously observed in the data corresponding to clusters. Some of these clusters have properties similar to high p{sub T} jets. A detailed study of these jet-like clusters is described, and comparisons with some counter experiments are discussed

Research program in experimental high energy physics, Task B

Two prototype tracking system modules of the LVD detector have been produced by the direct-mount method and tested. The direct-mount procedure was proposed by a subgroup (mainly US) of the LVD Collaboration. This method has the advantages over the previous (hood) design of greater signal-to-noise ratio, of providing spacing between the two streamer chamber layers of each tracking plane to improve track reconstruction and angular resoluation, economy and speed of production. The tests have shown very satisfactory performance, both of the mechanical aspects and of the read-out electronic which are principally Brown's responsibility. The Collaboration has agreed to proceed with production by this method. The full boot node data acquisition computer and one tower microvax, both provided by the Brown group, have been installed Hall A of Gran Sasso, where data acquisition development will proceed. FNAL Experiment E782, a study of the interactions of muons from the Tevatron, using an upgraded version of the E745 hybrid system, is now running at Fermilab. During the past year, film analysis of the 1987 run of E745, a study of the interactions of muon neutrinos, was essentially completed and a data summary tape is being produced. Also during the past year, analysis has continued both on the data of our experiments on interactions of hadrons with protons and heavier nuclei (FNAL E565, E570, E299, E154) and on the data of SLAC experiments BC72/73/75, studying the interactions in hydrogen of 20GeV/c photons