2,006,948 research outputs found
Search for stellar gravitational collapse by MACRO: Characteristics and results
No full textThe first MACRO lower supermodule has been sensitive to antineutrinos from stellar gravitational collapse since spring 1989. The results with the 44 tonnes of liquid scintillator which have been instrumented to search for stellar gravitational collapse are discussed here
Study of primary interactions with multiple muons in MACRO
No full textThe 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
Macro Supreme
No full textMacro Supreme is similarly valuable in this association that makes the body start getting fit as a fiddle now. faster rate than an eating routine alone. By showing up earlier, the body can begin to get more fit in two or three days rather than weeks. The use of Macro Supreme use of an upgrade can help clients with enteringMacro Suprem
Measurements of atmospheric muon neutrino oscillations, global analysis of the data collected with MACRO detector.
No full textThe 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 about 5σ, while the hypothesis of νμ → ντ oscillation gives a satisfactory description of all data.
The parameters with highest probability in a two flavor scenario are sin2 2θm = 1 and ∆m2 = 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
Measurements of atmospheric muon neutrino oscillations, global analysis of the data collected with MACRO detector
No full textThe 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 ∼ 5σ, while the hypothesis of νμ → ντ oscillation gives a satisfactory description of all data.
The parameters with highest probability in a two flavor scenario are sin2 2θm = 1 and ∆m2 = 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
A MACRO sampler
Full text linkWe present results from approximately 2 years running with the MACRO detector. Most of these data were taken with one of the six supermodules of the final detector in operation. Using a sample of 1.8×106 muons with E≳1.4 TeV we have searched for an excess of muons of celestial origin over cosmic ray background. No evidence for steady point sources was found. The upper limit on the muon flux at 95% CL is typically 2×10−12 cm−2 sec−2. No evidence for time modulated point sources was found. The muon multiplicity distribution favors a ‘‘light’’ composition for cosmic ray primaries with ≊75% protons above ∼103 TeV. We have also searched for neutrino bursts from supernovae in our Galaxy. None were observed during the period Oct. 1989 to Feb. 1992. Our sensitivity to neutrino bursts from collapsing stars extends to ≊60% of the stars in the Galaxy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87712/2/1222_1.pd
Challenges in macro-finance modeling
Full text linkThis article discusses various challenges in the specification and implementation of "macro-finance" models in which macroeconomic variables and term structure variables are modeled together in a no-arbitrage framework. The author classifies macro-finance models into pure latent-factor models ("internal basis models") and models that have observed macroeconomic variables as state variables ("external basis models") and examines the underlying assumptions behind these models. Particular attention is paid to the issue of unspanned short-run fluctuations in macroeconomic variables and their potentially adverse effect on the specification of external basis models. The author also discusses the challenge of addressing features such as structural breaks and time-varying inflation uncertainty. Empirical difficulties in the estimation and evaluation of macro-finance models are also discussed in detail.Econometric models ; Macroeconomics
Low energy atmospheric muon neutrinos in MACRO
No full textWe present the measurement of two event samples induced by atmospheric v(mu) of average energy (E) over bar(v) similar to 4 GeV. In the first sample, a neutrino interacts inside the MACRO detector producing an upward-going muon leaving the apparatus. The ratio of the number of observed to expected events is 0.57 +/- 0.05(stat) +/- 0.06(syst) +/- 0.14(theor) with an angular distribution similar to that expected from the Bartol atmospheric neutrino flux. The second is a mixed sample of internally produced downward-going muons and externally produced upward-going muons stopping inside the detector. These two subsamples are selected by topological criteria; the lack of timing information makes it impossible to distinguish stopping from downgoing muons. The ratio of the number of observed to expected events is 0.71 +/- 0.05(stat) +/- 0.07(syst) +/- 0.18(theor). The observed deficits in each subsample is in agreement with neutrino oscillations, although the significance is reduced by the large theoretical errors. However, the ratio of the two samples causes a large cancellation of theoretical and of some systematic errors. With the ratio, we rule out the no-oscillation hypothesis at 95% c.l. Furthermore, the ratio tests the pathlength dependence of possible oscillations. The data of both samples and their ratio favor maximal mixing and Delta m(2) similar to 10(-3)-10(-2) eV(2). These parameters are in agreement with our results from upward throughgoing muons, induced by v(mu) of much higher energies. (C) 2000 Elsevier Science B.V. All rights reserved
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