A combined analysis technique for the search for fast magnetic monopoles with the MACRO detector

We describe a search method for fast moving ($\beta > 5 \times 10^{-3}$) magnetic monopoles using simultaneously the scintillator, streamer tube and track-etch subdetectors of the MACRO apparatus. The first two subdetectors are used primarily for the identification of candidates while the track-etch one is used as the final tool for their rejection or confirmation. Using this technique, a first sample of more than two years of data has been analyzed without any evidence of a magnetic monopole. We set a 90% CL upper limit to the local monopole flux of $1.5 \times 10^{-15} cm^{-2} s^{-1} sr^{-1}$ in the velocity range $5 \times 10^{-3} \le \beta \le 0.99$ and for nucleon decay catalysis cross section smaller than $\sim 1 mb$.Comment: 29 pages (12 figures). Accepted by Astroparticle Physic

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

Myocardial protection with and without leukocyte depletion: A comparative study on the oxidative stress

Abstract: We tested the hypothesis that controlled reperfusion with leukocyte-depleted blood could improve myocardial protection by reducing the oxidative stress in patients undergoing myocardial revascularization, Thirty-four patients receiving antegrade/retrograde blood cardioplegia were divided into: group A: 11 patients with ejection fractions (EF) less than 35%, treated with leukocyte-depleted controlled blood reperfusion, group B: 11 patients with EF less than 35% in whom no leukocyte depletion was performed, group C: 6 patients with EF more than 35% treated as group A and group D: 6 patients with EF more than 45% without leukocyte depletion, To asses the oxidative stress, we evaluated total, total oxidized (GSSX), and reduced glutathione (GSH) in coronary sinus plasma, immediately before cross-clamping the aorta (TO), and at O (T1), 15 (T2) and 30 (T3) min after unclamping it, In groups A and B a significant shift towards oxidation of redox status of glutathione (GSH/GSSX) at T1 vs TO was observed, Glutathione redox ratio remained low in group B while in group A it returned to the basal value at T2 with a significant difference from group B at T2 and T3, No differences were observed between groups C and D, In conclusion, our data show that leukocyte-depleted reperfusion can afford a better myocardial protection in patients with left ventricular dysfunction, while it seems unnecessary in patients with normal EF

Hadronic interaction features using multiple muon events deep underground

The MACRO underground experiment performed a systematic experimental study of muon bundle structure. The aim is to gain a better understanding of the features of high energy cosmic ray interactions. The reliability of the hadronic interaction model in reproducing the shower development features at the highest energy can be studied selecting high multiplicity muon bundles. We present here the analisys of the muon lateral distribution (decoherence function) based on two different method( detector dependent and detector independent method), the decoherence function in a high multiplicity event subsample and the search for muon clusters

Performance of the MACRO streamer tube system in the search for magnetic monopoles

0info:eu-repo/semantics/publishe

MACRO absolute muon flux measurement: Comparison with Monte Carlo predictions

The vertical muon intensity measured with MACRO at the Gran Sasso Laboratory, in the depth range 3200-7000 hg cm(-2) of standard rock, corresponding to 2-200 TeV/nucleon primary energy range, is presented. An estimation of the muon energy spectrum at the surface will also be shown. The results will be compared with those of other experiments and with the computation of the intensities obtained using a full Monte Carlo calculation with different hypotheses for the primary cosmic ray composition

High energy cosmic ray physics with underground muons in MACRO .2. Primary spectra and composition

Multimuon data from the MACRO experiment at Gran Sasso have been analyzed using a new method, which allows one to estimate the primary cosmic ray fluxes. The estimated all-particle spectrum is higher and flatter than the one obtained from direct measurements but is consistent with EAS array measurements. The spectral indexes of the fitted energy spectrum are 2.56 +/- 0.05 for E 5000 TeV with a gradual change at intermediate energies. The average mass number shows little dependence on the primary energy below 1000 TeV, with a value of 10.1 +/- 2.5 at 100 TeV. At higher energies the best fit average mass shows a mild increase with energy, even though no definite conclusion can be reached taking into account errors. The fitted spectra cover a range from similar to 50 TeV up to several thousand TeV

High energy cosmic ray physics with underground muons in MACRO .1. Analysis methods and experimental results

In this paper, the first of a two-part work, we present the reconstruction and measurement of muon events detected underground by the MACRO experiment at Gran Sasso (E-mu greater than or equal to 1.3 TeV in atmosphere). The main aim of this work is to discuss the muon multiplicity distribution as measured in the detector. The data sample analyzed consists of 4.4 x 10(6) muon events, of which similar to 263 000 are multiple muons, corresponding to a total live time of 5850 h. In this sample, the observed multiplicities extend above N-mu = 35, with intermuon separations up to 50 m and beyond. Additional complementing measurements, such as the inclusive muon Aux, the angular distribution, and the muon separation distribution (decoherence), are also included. The physical interpretation of the results presented here is reported in the following companion paper

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