189904802
Parity Violation in Electron Quasi-Elastic Scattering
Parity violating electron scattering on a nucleus in the quasi-elastic region is investigated within a relativistic single particle model from 208Pb and with the incident electron energy up to 1 GeV. We discuss the effect of nucleon electromagnetic form factors by comparing the standard Sachs form factors with the parameterized form recently adjusted to the world data. The effect of the strangeness is also investigated through the recent results of the strangeness form factors, and we separately calculate the asymmetries of longitudinal and transverse response functions.
119821537
The in-medium effects on the neutrino reaction in dense matter
The nucleon form factors in free space are usually thought to be modified when a nucleon is bound in a nucleus or immersed in a nuclear medium. We investigated effects of the density-dependent axial and weak-vector form factors on the electro-neutrino (νe) and anti-electro-neutrino (νe) reactions with incident energy Ev ≤ 80 MeV via neutral current (NC) and charged current (CC) for a nucleon in a nuclear medium or 12C. For the density-dependent form factors, we exploited the quark-meson-coupling (QMC) model, and apply them to the νe and νe induced reactions by NC and CC. In CC reaction, about 5 % decrease of the electro neutrino (νe) reaction cross section on the nucleon is shown to be occurred in normal density, ρ = ρ0∼0.15fm−3, and also about 5 % reduction of total νe cross section on 12C is obtained by the modification of the weak form factors for bound nucleons. Density effects for both cases are relatively small, but they are as large as the effect by the Coulomb distortion of outgoing leptons in t...
121132966
ANALYSES OF THE KAON PHOTO- AND ELECTRO-PRODUCTION IN THE ISOBAR MODEL
37323655
Coulomb sum rule in the quasielastic region
Within a relativistic single particle model, we calculate the Coulomb sum rule of inclusive electron scattering from {sup 40}Ca and {sup 208}Pb in the quasielastic region. Theoretical longitudinal and transverse structure functions are extracted for three-momentum transfers from 300 to 500 MeV/c and compared with the experimental data measured at Bates and Saclay. We find that there is no drastic suppression of the longitudinal structure function and that the Coulomb sum rule depends on the nucleus in our theoretical model.
121016358
Lifetime of a Nuclear Excited State in Cascade Decay
It is shown that the lifetime of a nuclear excited state in the region of femtoseconds could be accurately measured by a precision measurement facility of a flat crystal spectrometer, if the angular correlation of two successive γ-rays in cascade decay is taken into account in the Doppler shift attenuation method.
119204961
Ambiguities of neutrino (antineutrino) scattering on the nucleon due to the uncertainties of relevant strangeness form factors
Strange quark contributions to the neutrino (antineutrino) scattering on the nucleon level are investigated in the quasi-elastic region. Incident energy is used at 500 MeV for the scattering. All of the physical observables by the scattering are investigated within available experimental and theoretical results for strangeness form factors of the nucleon. Specifically, a newly combined datum of the parity violating electron scattering and the neutrino scattering is exploited for the strangeness form factors. Feasible quantities to be explored for the strangeness contents are discussed for the application to the neutrino–nucleus scattering.
118406337
Coherent/incoherent metal transition in a holographic model
A bstractWe study AC electric (σ), thermoelectric (α), and thermal κ¯$$ \left(\overline{\kappa}\right) $$ conductivities in a holographic model, which is based on 3+1 dimensional Einstein-Maxwell-scalar action. There is momentum relaxation due to massless scalar fields linear to spatial coordinate. The model has three field theory parameters: temperature (T), chemical potential (μ), and effective impurity (β). At low frequencies, if β < μ, all three AC conductivities (σ, α,κ¯$$ \overline{\kappa} $$) exhibit a Drude peak modified by pair creation contribution (coherent metal). The parameters of this modified Drude peak are obtained analytically. In particular, if β ≪ μ the relaxation time of electric conductivity approaches to 23μ/β2$$ 2\sqrt{3\mu }/{\beta}^2 $$ and the modified Drude peak becomes a standard Drude peak. If β > μ the shape of peak deviates from the Drude form (incoherent metal). At intermediate frequencies (T < ω < μ), we have analysed numerical data of three conductivities (σ, α,κ¯$$ \overline{\kappa} $$) for a wide variety of parameters, searching for scaling laws, which are expected from either experimental results on cuprates superconductors or some holographic models. In the model we study, we find no clear signs of scaling behaviour.
17742099
Cosmic-ray tests for quality control of the CDF plug upgrade EM calorimeter and the CDF plug preshower detector
The CDF Plug Upgrade electromagnetic (EM) calorimeter and the preshower detector consist of tile-"ber elements forming a projective tower geometry. Each of the 23 longitudinal layers is separated into 24 units in the azimuthal direction. Cosmic-ray tests as a quality control of these mechanically basic units, called the 153 units, were carried out since January 1995 and completed in June 1996. All the units amounting to a total 1200 units were processed. By using HAMAMASU R4125 for the photon readout, the average light yields were measured to be 5.8 and 21 photoelectrons for the EM and the preshower units, respectively. The light yield variation along the longitudinal layers of EM tower was measured to be 10%. A GEANT-simulation study using the results of the cosmic-ray tests was performed for a realistic calorimeter con"guration. It was found that the simulated energy resolution was consistent with the requirement of *E/E"J(16%)2/E#(1%)2 (E in GeV). Adding preshower response to EM response improved in particular the linearity of the calorimeter. It was possible to achieve the non-linearity of 1% level for energies in the range of 10}200 GeV. ( 2000 Elsevier Science B.V. All rights reserved.