7 research outputs found
On inconsistency of experimental data on primary nuclei spectra with sea level muon intensity measurements
For the first time a complete set of the most recent direct data on primary
cosmic ray spectra is used as input into calculations of muon flux at sea level
in wide energy range GeV. Computations have been performed
with the CORSIKA/QGSJET and CORSIKA/VENUS codes. The comparison of the obtained
muon intensity with the data of muon experiments shows, that measurements of
primary nuclei spectra conform to sea level muon data only up to several tens
of GeV and result in essential deficit of muons at higher energies. As it
follows from our examination, uncertainties in muon flux measurements and in
the description of nuclear cascades development are not suitable to explain
this contradiction, and the only remaining factor, leading to this situation,
is underestimation of primary light nuclei fluxes. We have considered
systematic effects, that may distort the results of the primary cosmic ray
measurements with the application of the emulsion chambers. We suggest, that
re-examination of these measurements is required with the employment of
different hadronic interaction models. Also, in our point of view, it is
necessary to perform estimates of possible influence of the fact, that sizable
fraction of events, identified as protons, actually are antiprotons. Study of
these cosmic ray component begins to attract much attention, but today nothing
definite is known for the energies GeV. In any case, to realize whether
the mentioned, or some other reasons are the sources of disagreement of the
data on primaries with the data on muons, the indicated effects should be
thoroughly analyzed
Measurements of atmospheric muon neutrino oscillations, global analysis of the data collected with MACRO detector
The final analysis of atmospheric neutrino events collected with the MACRO detector is presented. Three different classes of events, generated by neutrinos in different energy ranges, are studied looking at rates, angular distributions and estimated energies. The results are consistent for all the subsamples and indicate a flux deficit that depends on energy and path - length of neutrinos. The no - oscillation hypothesis is excluded at similar to 5sigma, while the hypothesis of nu(mu) --> nu(tau) oscillation gives a satisfactory description of all data. The parameters with highest probability in a two flavor scenario are sin(2) 2theta(m) = 1 and Deltam(2) = 0.0023 eV(2). This result is independent of the absolute normalization of the atmospheric neutrino fluxes. The data can also be used to put experimental constrain on this normalization
Measurements of atmospheric muon neutrino oscillations,global analysis of the data collected with MACRO detector
The final analysis of atmospheric neutrino events collected with the MACRO detector is presented.
Three different classes of events, generated by neutrinos in different energy ranges, are studied looking at
rates, angular distributions and estimated energies. The results are consistent for all the subsamples and
indicate a flux deficit that depends on energy and path-length of neutrinos. The no-oscillation hypothesis
is excluded at ⌠5Ï, while the hypothesis of ΜΌ â ÎœÏ oscillation gives a satisfactory description of all data.
The parameters with highest probability in a two flavor scenario are sin2 2Ξm= 1 and Îm2 = 0.0023 eV2.
This result is independent of the absolute normalization of the atmospheric neutrino fluxes. The data can
also be used to put experimental constrain on this normalization
Muon astronomy with the MACRO detector
We have analyzed a sample of 1.8 x 10(6) muons with E(mu) greater-than-or-similar-to 1.3 TeV collected by the first and second supermodules of the MACRO detector at Gran Sasso during the period 1989 February to 1991 February. We have searched for an excess of muons of celestial origin over cosmic-ray background. Our search for steady sources in solid angle bins of DELTAOMEGA almost-equal-to 3.0-degrees x 3.0-degrees in the declination range -5-degrees less-than-or-equal-to delta less-than-or-equal-to 90-degrees was negative; the upper limit with 95% C.L. to the muon flux at mid-latitudes (delta approximately 45-degrees) is J(mu)steady less-than-or-similar-to 2 x 10(-12) cm-2 s-1. In addition, we have searched for muon excesses modulated by the orbital period of selected X-ray sources, including Cyg X-3, Cyg X-1, Her X-1, 4U 0115+63, and 4U 1907+09. For Cyg X-3 we obtained an upper limit with 95% C.L. of J(mu)mod less-than-or-equal-to 8.8 x 10(-13) cm-2 s-1. Further, we have no evidence of any bursting activity from Cyg X-3, during our search period, which includes the radio outburst of 1991 January
MUON ASTRONOMY WITH THE MACRO DETECTOR
We have analyzed a sample of 1.8 x 10(6) muons with E(mu) greater-than-or-similar-to 1.3 TeV collected by the first and second supermodules of the MACRO detector at Gran Sasso during the period 1989 February to 1991 February. We have searched for an excess of muons of celestial origin over cosmic-ray background. Our search for steady sources in solid angle bins of DELTAOMEGA almost-equal-to 3.0-degrees x 3.0-degrees in the declination range -5-degrees less-than-or-equal-to delta less-than-or-equal-to 90-degrees was negative; the upper limit with 95% C.L. to the muon flux at mid-latitudes (delta approximately 45-degrees) is J(mu)steady less-than-or-similar-to 2 x 10(-12) cm-2 s-1. In addition, we have searched for muon excesses modulated by the orbital period of selected X-ray sources, including Cyg X-3, Cyg X-1, Her X-1, 4U 0115+63, and 4U 1907+09. For Cyg X-3 we obtained an upper limit with 95% C.L. of J(mu)mod less-than-or-equal-to 8.8 x 10(-13) cm-2 s-1. Further, we have no evidence of any bursting activity from Cyg X-3, during our search period, which includes the radio outburst of 1991 January
Calibrations of CR39 and Makrofol nuclear track detectors and search for exotic particles
We present the final results of the search for exotic massive particles in the cosmic radiation performed with the MACRO underground experiment. Magnetic monopoles and nuclearites flux upper limits obtained with the CR39 nuclear track subdetector, the scintillation and streamer tube subdetectors are given. Searches at high altitude with the SLIM experiment are in progress