Weak reactions on 12C within the Continuum Random Phase Approximation with partial occupancies

We extend our previous studies of the neutrino-induced reactions on 12C and muon capture to include partial occupation of nuclear subshells in the framework of the continuum random phase approximation. We find, in contrast to the work by Auerbach et al., that a partial occupation of the p1/2 subshell reduces the inclusive cross sections only slightly. The extended model describes the muon capture rate and the 12C(nu_e,e-)12N cross section very well. The recently updated flux and the improved model bring the calculated 12C(nu_mu,mu^-)12N cross section (~ 17.5 10^{-40} cm^2) and the data (12.4 +/- 0.3(stat.) +/- 1.8(syst.) 10^{-40} cm^2) closer together, but does not remove the discrepancy fully.Comment: 12 pages, 2 figure

Estimates of weak and electromagnetic nuclear decay signatures for neutrino reactions in Super-Kamiokande

We estimate possible delayed β decay signatures of the neutrino induced reactions on 16O in a two-step model: the primary neutrino (ν,l) process, where l is the lepton in the final state, is described within the random phase approximation, while the subsequent decay of the excited nuclear state in the final channel is treated within the statistical model. We calculate partial reaction cross sections leading to β unstable nuclei. We consider neutrino energies up to 500 MeV, relevant for atmospheric neutrino detection in Super-Kamiokande, and supernova neutrino spectra

Propagation considerations in land mobile satellite transmission

It appears likely that the Land Mobile Satellite Services (LMSS) will be authorized by the FCC for operation in the 800 to 900 MHz (UHF) and possibly near 1500 MHz (L-band). Propagation problems are clearly an important factor in the effectiveness of this service, but useful measurements are few, and produced contradictory interpretations. A first order overview of existing measurements is presented with particular attention to the first two NASA balloon to mobile vehicle propagation experiments. Some physical insight into the interpretation of propagation effects in LMSS transmissions is provided

Quasielastic neutrino scattering from oxygen and the atmospheric neutrino problem

We examine several phenomena beyond the scope of Fermi-gas models that affect the quasielastic scattering (from oxygen) of neutrinos in the 0.1 -- 3.0 GeV range. These include Coulomb interactions of outgoing protons and leptons, a realistic finite-volume mean field, and the residual nucleon-nucleon interaction. None of these effects are accurately represented in the Monte Carlo simulations used to predict event rates due to $\mu$ and $e$ neutrinos from cosmic-ray collisions in the atmosphere. We nevertheless conclude that the neglected physics cannot account for the anomalous $\mu$ to $e$ ratio observed at Kamiokande and IMB, and is unlikely to change absolute event rates by more than 10--15\%. We briefly mention other phenomena, still to be investigated in detail, that may produce larger changes.Comment: In Revtex version 2. 14 pages, 3 figures (available on request from J. Engel, tel. 302-831-4354, [email protected]

Neutrino–nucleus reactions and nuclear structure

The methods used in the evaluation of the neutrino–nucleus cross section are reviewed. Results are shown for a variety of targets of practical importance. Many of the described reactions are accessible in future experiments with neutrino sources from the pion and muon decays at rest, which might be available at the neutron spallation facilities. Detailed comparison between the experimental and theoretical results would establish benchmarks needed for verification and/or parameter adjustment of the nuclear models. Having a reliable tool for such calculation is of great importance in a variety of applications, e.g. the neutrino oscillation studies, detection of supernova neutrinos, description of the neutrino transport in supernovae and description of the r-process nucleosynthesis

Reactor antineutrino spectra and their application to antineutrino-induced reactions. II

The antineutrino and electron spectra associated with various nuclear fuels are calculated. While there are substantial differences between the spectra of different uranium and plutonium isotopes, the dependence on the energy and flux of the fission-inducing neutrons is very weak. The resulting spectra can be used for the calculation of the antineutrino and electron spectra of an arbitrary nuclear reactor at various stages of its refueling cycle. The sources of uncertainties in the spectrum are identified and analyzed in detail. The exposure time dependence of the spectrum is also discussed. The averaged cross sections of the inverse neutron β decay, weak charged and neutral-current-induced deuteron disintegration, and the antineutrino-electron scattering are then evaluated using the resulting ν̅_e spectra. [RADIOACTIVITY, FISSION 235U, 238U, (^239)Pu, (^240)Pu, (^241)Pu, antineutrino and electron spectra calculated. σ for ν̅ induced reactions analyzed.

How Sensitive are Di-Leptons from Rho Mesons to the High Baryon Density Region?

We show that the measurement of di-leptons might provide only a restricted view into the most dense stages of heavy ion reactions. Thus, possible studies of meson and baryon properties at high baryon densities, as e.g. done at GSI-HADES and envisioned for FAIR-CBM, might observe weaker effects than currently expected in certain approaches. We argue that the strong absorption of resonances in the high baryon density region of the heavy ion collision masks information from the early hot and dense phase due to a strong increase of the total decay width because of collisional broadening. To obtain additional information, we also compare the currently used approaches to extract di-leptons from transport simulations - i.e. shining, only vector mesons from final baryon resonance decays and instant emission of di-leptons and find a strong sensitivity on the method employed in particular at FAIR and SPS energies. It is shown explicitly that a restriction to rho meson (and therefore di-lepton) production only in final state baryon resonance decays provide a strong bias towards rather low baryon densities. The results presented are obtained from UrQMD v2.3 calculations using the standard set-up.Comment: 8 pages, 6 figures, expanded versio

Measurement of I-129 in environmental samples by ICP-CRI-QMS: possibilities and limitations

129I is preconcentrated from environmental samples and its accessibility is addressed for inductively coupled plasma quadrupole mass spectrometer with collision/reaction interface (ICP-CRI-QMS). By applying oxygen as CRI gas through skimmer cone, the signal of the interfering 129Xe from the impurity of plasma gas can be eliminated while the formation of 127I1H1H+ can be partially removed. The improved ICP-QMS can be employed for investigation of 129I in environmental samples with a 129I/127I ratio down to 10-7. The detection capability was demonstrated by measuring 129I in seaweed samples collected around the nuclear fuel reprocessing plant at La Hague. The abundant 127I in the sample matrix causes a serious problem and degrades the detection capability of the instrument when the concentration of 127I is larger than 105ng/g. Even combined with a sufficient pre-concentration procedure, ICP-QMS is not considered as a suitable technique for the analysis of 129I in uncontaminated environmental samples with 129I/127I ratio of less than 10-7. Results are presented for seaweed samples collected around La Hague. In addition, time dependant I concentrations and ratios are given for colloids and water sampled from Lake Thu

Inclusive 12C(νμ,μ)12N reaction in the continuum random phase approximation

Motivated by a recent experiment at LAMPF we calculate cross sections for muon-neutrino and muon-antineutrino charged-current reactions on 12C within the continuum RPA model. We also determine the branching ratios for the main decay channels of these reactions by application of a statistical model