Search results for "Muon"
showing 10 items of 1376 documents
Underground multimuon experiment in the Pyhäsalmi mine
2006
An experiment to observe simultaneous, multiple muon events originating from extensive air showers is under preparation. The experiment will be situated in shallow depths in the Pyhasalmi mine in Finland, where the existing free caverns will be used. The aim is to cover an area of about 200 - 300 m(2). The detection of the multimuon events is motivated by partly unknown composition of the primary cosmic rays in the energy region of 10(15) - 10(16) eV, i.e. the 'knee' region. A prototype detector is under construction and is expected to be running at the spring 2005.
Muon states in metals: Recent progress
1984
We report on our results in two interesting questions related to muon spin rotation studies in condensed matter: (i) energetics of muons in metals, including lattice relaxation and zero point motion in self-trapping phenomena, and (ii) systematics of Knight shifts and hyperfine fields.
Study of the rare Bs0 and B0 decays into the π+π−μ+μ− final state
2015
A search for the rare decays B0s→π+π−μ+μ− and B0→π+π−μ+μ− is performed in a data set corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV. Decay candidates with pion pairs that have invariant mass in the range 0.5-1.3 GeV/c2 and with muon pairs that do not originate from a resonance are considered. The first observation of the decay B0s→π+π−μ+μ− and the first evidence of the decay B0→π+π−μ+μ− are obtained and the branching fractions are measured to be B(B0s→π+π−μ+μ−)=(8.6±1.5(stat)±0.7(syst)±0.7(norm))×10−8 and B(B0→π+π−μ+μ−)=(2.11±0.51(stat)±0.15(syst)±0.16(norm))×10−8, where the third unc…
Nuclear effects in neutrino production of Δ at intermediate energies
1998
Abstract The neutrino production of Δ in 16 O has been studied at intermediate energies relevant to atmospheric neutrino experiments. The Δ production cross sections with electrons or muons in the final state is found to be reduced due to nuclear effects. This reduction is even larger for the accompanying one pion production cross sections. The ratio of electron to muon production cross sections, however, does not show any significant dependence on nuclear medium effects.
Measurement of the proton and deuteron structure functions, F2p and F2d, and of the ratio
1997
The muon-proton and muon-deuteron inclusive deep inelastic scattering cross sections were measured in the kinematic range 0.002 < x < 0.60 and 0.5 < Q(2) < 75 GeV2 at incident muon energies of 90, 120, 200 and 280 GeV. These results are based on the full data set collected by the New Muon Collaboration, including the data taken with a small angle trigger. The extracted values of the structure functions F-2(p) and F-2(d) are in good agreement with those from other experiments. The data cover a sufficient range of y to allow the determination of the ratio of the longitudinally to transversely polarised virtual photon absorption cross sections, R = sigma(L)/sigma(T), for 0.002 < x < 0.12. The …
Analysis of the 2νββ decay and muon capture reactions for the mass A = 46 and A = 48 nuclei using the nuclear shell model
2005
We discuss the two-neutrino double-beta decays of 46Ca and 48Ca by using the nuclear shell model with well-tested two-body interactions. We also discuss the ordinary muon-capture (OMC) reaction on the final nuclei, 46Ti and 48Ti, of these decays. The OMC leads to the virtual states of the intermediate nuclei, 46Sc and 48Sc, in these double-beta decays.
HADRONIC CROSS SECTION MEASUREMENT AT BES-III
2014
Measurements of the R ratio are closely related to two pre quantities, the anomalous magnetic moment of the muon (g - 2), and the value of the electromagnetic fine structure constant [Formula: see text]. Hadronic contributions to both quantities can be derived via dispersion integrals, using experimental R data as input. For the phenomenological evaluations of these contributions, different energy ranges of hadronic cross section data are required. At BES-III, Initial State Radiation (ISR) from an existing Ψ(3770) dataset will be used for measurements of hadronic cross sections below [Formula: see text], while for higher energies a dedicated energy scan program will be performed up to [For…
Measurements of relativistic time dilatation for positive and negative muons in a circular orbit
1977
The lifetimes of both positive and negative relativistic (γ = 29.33) muons have been measured in the CERN Muon Storage Ring with the results τ+ = 64.419 (58) µs, τ− = 64.368 (29) µs The value for positive muons is in accordance with special relativity and the measured lifetime at rest: the Einstein time dilation factor agrees with experiment with a fractional error of 2×10−3 at 95% confidence. Assuming special relativity, the mean proper lifetime for μ− is found to be τ0− = 2.1948(10) µs the most accurate value reported to date. The agreement of this value with previously measured values of τ0+ confirms CPT invariance for the weak interaction in muon decay.
Total muon-capture rate. Application to11B
1972
A study of the total muon-capture rate in nuclei is presented, with the aid of the impulse and closure approximations and under the assumption that the initial nucleus can be described by a mixing of states in theJ-scheme. The theory is applied to the process of muon capture in11B, with a discussion on the value of the average neutrino momentum.
Radiative muon capture on 12C and 16O
1979
Abstract We study exclusive radiative muon capture on 12 C(g.s.) leading to 12 B(g.s.), and on 16 O(g.s.) leading to 16 N(0 − , 120 keV). Our investigation, which is based on impulse approximation, puts special emphasis on elementary particle aspects of radiative capture, such as tests of magnitude and momentum transfer dependence of the induced pseudoscalar, and possible contributions of axial currents of second kind (weak electricity). We calculate several correlation observables which are sensitive to the nucleonic currents but depend very little on the structure of the nuclear initial and final states. In particular, it is shown that in capture on 12 C the polarization and alignment of …