Search results for "wave function"
showing 10 items of 395 documents
Meson exchange and isobar admixture contributions to elastic electron-deuteron scattering
1974
The deuteron structure functions for elastic electron scattering and the deuteron static properties have been calculated with the inclusion of isobar admixtures to the deuteron wave function and meson exchange currents. At higher momentum transfers the structure functions are increased significantly because of the strong enhancement of the deuteron magnetic dipole form factor. Roughly 15–35% of this enhancement depending on the momentum transfer arise from the meson exchange currents.
Second-forbidden nonunique $$\beta ^-$$ decays of $$^{59,60}$$Fe:possible candidates for $$g_{\mathrm{A}}$$ sensitive electron spectral-shape measure…
2021
In this work, we present a theoretical study of the electron spectral shapes for the second-forbidden nonunique $\beta^-$-decay transitions $^{59}\textrm{Fe}(3/2^-)\to\,^{59}\textrm{Co}(7/2^-)$ and $^{60}\textrm{Fe}(0^+)\to\,^{60}\textrm{Co}(2^+)$ in the framework of the nuclear shell model. We have computed the involved wave functions by carrying out a complete $0\hbar\omega$ calculation in the full $fp$ model space using the KB3G and GXPF1A effective interactions. When compared with the available data, these interactions predict the low-energy spectra and electromagnetic properties of the involved nuclei quite successfully. This success paves the way for the computations of the $\beta$-de…
NUCLEAR PROPERTIES FOR ASTROPHYSICAL AND RADIOACTIVE-ION-BEAM APPLICATIONS
1997
Abstract We tabulate the ground-state odd-proton and odd-neutron spins and parities, proton and neutron pairing gaps, one- and two-neutron separation energies, quantities related to β -delayed one- and two-neutron emission probabilities, average energy and average number of emitted neutrons, β -decay energy release and half-life with respect to Gamow–Teller decay with a phenomenological treatment of first-forbidden decays, one- and two-proton separation energies, and α -decay energy release and half-life for 9318 nuclei ranging from 16O to 339136 and extending from the proton drip line to the neutron drip line. This paper is a new and improved version of Atomic Data And Nuclear Data Table…
Alpha-cluster model for 8Be and 12C with correlated alpha particles
2001
Abstract An alpha-cluster model is proposed for 8Be and 12C nuclei, within the framework of the resonating group method (RGM). The composing 4He clusters are described using Jastrow-correlated translationally invariant configuration-interaction (Jastrow-TICI2) wave functions. The ground-state energies of the nuclei are computed by means of a Metropolis Monte-Carlo sampling.
NUCLEAR EFFECTS IN NEUTRINO INDUCED REACTIONS
2008
We discuss the relevance of nuclear medium effects in the analysis of some low and medium energy neutrino reactions of current interest. In particular, we study the Quasi-Elastic (QE) process, where RPA correlations and Final State Interactions (FSI) are shown to play a crucial role. We have also investigated the neutrino induced coherent pion production. We find a strong reduction of the cross section due to the distortion of the pion wave function and the modification of the production mechanisms in the nucleus. The sensitivity of the results to the axial $N\Delta$ coupling $C_5^A(0)$ has been also investigated.
Short-range correlations and neutrinoless double beta decay
2007
In this work we report on the effects of short-range correlations upon the matrix elements of neutrinoless double beta decay. We focus on the calculation of the matrix elements of the neutrino-mass mode of neutrinoless double beta decays of 48Ca and 76Ge. The nuclear-structure components of the calculation, that is the participant nuclear wave functions, have been calculated in the shell-model scheme for 48Ca and in the proton-neutron quasiparticle random-phase approximation (pnQRPA) scheme for 76Ge. We compare the traditional approach of using the Jastrow correlation function with the more complete scheme of the unitary correlation operator method (UCOM). Our results indicate that the Jast…
Gamow-Teller decay ofZn80: Shell structure and astrophysical implications
1988
Gamow-Teller \ensuremath{\beta} decay of $^{80}\mathrm{Zn}$ to levels in $^{80}\mathrm{Ga}$ has been calculated from a random-phase-approximation shell model with Nilsson model wave functions. The predicted features are compared to existing experimental results. Gross \ensuremath{\beta}-decay properties as well as quasiparticle structure indicate shape coexistence for $^{80}\mathrm{Ga}$. This result implies a rather rapid weakening of the shell strength far from \ensuremath{\beta} stability above $_{28}^{78}\mathrm{Ni}_{50}$. The nuclear properties of $^{80}\mathrm{Zn}$ as an astrophysical ``waiting-point'' nucleus suggest that the r-process scenario which is responsible for the solar r abu…
Manifestation of the halo structure in momentum distributions from 6He fragmentation
1998
Abstract Experimental data on the momentum distribution in the fragmentation of a 240 MeV/u 6 He beam on a carbon target are compared with several models of the 6 He nucleus based on different physical assumptions. It is shown that the lack of a strict theoretical description of the fragmentation mechanism and, in particular, of the final state interaction prevents any contra or versa arguments for these models. The requirement of fragment ( 5 He) survival or spatial localization of a fragment in the 6 He wave function is an essential point in the reaction mechanism. The analysis of the 5 He momentum (sum of the neutron and the α-particle momenta) distribution is free from the effect of fin…
Plausible explanation for theΔ5/2+(2000)puzzle
2011
From a Faddeev calculation for the $\ensuremath{\pi}$-$(\ensuremath{\Delta}\ensuremath{\rho}){}_{{N}_{5/{2}^{\ensuremath{-}}}(1675)}$ system we show the plausible existence of three dynamically generated $I({J}^{P})=3/2(5/{2}^{+})$ baryon states below 2.3 GeV, whereas only two resonances, ${\ensuremath{\Delta}}_{5/{2}^{+}}(1905)(****)$ and ${\ensuremath{\Delta}}_{5/{2}^{+}}(2000)(**),$ are cataloged in the Particle Data Book Review. Our results give theoretical support to data analyses extracting two distinctive resonances, ${\ensuremath{\Delta}}_{5/{2}^{+}}(~$1740) and ${\ensuremath{\Delta}}_{5/{2}^{+}}(~$2200), from which the mass of ${\ensuremath{\Delta}}_{5/{2}^{+}}(2000)(**)$ is estima…
Configuration mixing and total muon capture rates
1973
Abstract We modify the Primakoff closure approximation to get independence on the mean neutrino energy and energy weighted sum rules are used for the corrective terms. A near model - independent discussion is then possible, and the total rates are shown to be a very sensitive tool to investigate configuration mixing of the target. Wild discrepancies with experiment would arise if the limit of pure jj or LS couplings are used for 12 C, whereas the Cohen-Kurath wave function gives a very good result.