123347235
Inclusive charged-current neutrino-nucleus scattering in the quasielastic region
We study inclusive charged-current reaction through total cross sections of neutrino-nucleus scattering within the framework of a relativistic single-particle model in the quasielastic region. To describe the final-state interaction between knocked-out nucleons and the residual nucleus, a real potential of final nucleons, which is generated by a relativistic mean field, is used with the assumption of no loss of flux, which leads to current conservation and gauge invariance. We calculate ({nu}{sub {mu},{mu}}{sup -}) and ({nu}-bar{sub {mu},{mu}}{sup +}) reactions. In these calculations, {sup 12}C, {sup 40}Ca, and {sup 208}Pb are used as target nuclei and the incident neutrino (antineutrino) energies are exploited up to 4 GeV. We find that the effect of the final-state interaction by the real potential of the knocked-out nucleons reduces cross sections by about 15%, similar to the effect of electron scattering. Furthermore, the effect of the Coulomb distortion for the outgoing leptons is shown to be different from the electron scattering. Finally, our total cross sections by scaling number of participated nucleons are presented to compare with experimental data.
116255134
Roles of Direct Break-up Reaction on Neutrino Scattering off $^{12}$C near Nucleon Threshold Region
Neutrino (antineutrino) scattering off $^{12}$C is one of various important key reactions for $\nu$-process in the nucleosysnthesis of light nuclei. Most of neutrino-nucleus scattering are considered through indirect processes within the energy range from a few to tens of MeV. Target nuclei are excited by incident neutrino (antineutrino) through various transitions, and subsequently decay into other nuclei with emitting particles. But, direct processes are also feasible, in which incident neutrino (antineutrino) strips directly one nucleon from target nuclei. Consequently, direct processes may affect abundances of $^{11}$C and $^{11}$B additionally to indirect processes. We investigate direct neutrino (antineutrino) quasi-elastic scattering off $^{12}$C around the energy region liberating one nucleon and discuss implications of direct processes in the nucleosynthesis. The direct processes might be comparable to the indirect processes if the final state interaction is taken into account.
121427481
Investigating the Suppressions for the Longitudinal Structure Function in High Energy Quasielastic Scattering from 56Fe
We investigate the cross sections for inclusive (e, e') reaction from 56 Fe in quasielastic region at large electron energies (2-4GeV) and large three momentum transfer (0.5-1.5 GeV/c). We use a relativistic mean-field single particle model for the bound and continuum nucleon wave functions based on the σ-ω model and we include the effects of electron Coulomb distortion in the calculation. The results are compared to high energy data from SLAC and more recent data from Jefferson Laboratory, particularly for the kinematics where the quasielastic process is expected to dominate the cross section with the energy transfer less than 500 to 600 MeV. The effects of the predicted weakening of the strong scalar and vector potentials of the σ-ω model at high energy are discussed. Possible evidence for "longitudinal suppression" or modifications of nucleon form factors in the medium is considered, but neither is necessary to explain the quasielastic data for four momentum transfers less than 1 (GeV/c) 2 .
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...
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.
122428021
ANALYSIS OF PION WEAK-PRODUCTION NEAR THRESHOLD BY MULTIPOLE AMPLITUDES
By exploiting the chiral Ward identities based on the QCD Lagrangian for pion weak production, we derive a transition amplitude by the weak current and show analytical results of relevant multipole amplitudes without any expansion. Their physical implications and numerical results are also discussed.
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.