Renormalization of the one-body off-diagonal Coulomb field in nuclei

Isospin violation effects in nuclei are investigated within a microscopic approach which takes into account the influence of the residual strong interaction on the Coulomb interaction. The renormalization of the off-diagonal Coulomb field acting within a nucleus, by the residual strong interaction is calculated analytically in a simplified RPA. From the expression for the suppression coefficient of the isospin violating part of the Coulomb field, the isospin violating spreading widths of isobaric analog states are derived. The resulting reduction of the width is in agreement with the data on the isospin symmetry restoration and with some earlier evaluations of the isospin violating spreading widths.Comment: 11 pages, Late

SU(2,1) Dynamics of Multiple Giant Dipole Resonance Coulomb Excitation

We construct a three-dimensional analytically soluble model of the nonlinear effects in Coulomb excitation of multiphonon Giant Dipole Resonances (GDR) based on the SU(2,1) algebra. The full 3-dimensional model predicts further enhancement of the Double GDR (DGDR) cross sections at high bombarding energies. Enhancement factors for DGDR measured in thirteen different processes with various projectiles and targets at different bombarding energies are well reproduced with the same value of the nonlinearity parameter with the exception of the anomalous case of $^{136}$Xe which requires a larger value.Comment: 10 pages, 3 Postscript figures, late

Structure of Low-Energy Collective 0−0^{-}-States in Doubly Magic Nuclei and Matrix Elements of the P-odd and P- and T-odd Weak Interaction

The structure of the collective low-energy $J^{\pi}=0^{-}$ (T=0 and T=1) modes is studied for a doubly magic nucleus in a schematic analytic model of RPA. The $0^{-}$ phonon states ($T= 0,1$) lie at energies E_{T=0}(0^{-}) \alt \omega and $E_{T=1}(0^{-}) > \omega$, where $\omega$ is the oscillator frequency. The matrix elements of P-odd and P- and T-odd weak one-body potentials connecting the ground state to these $0^{-}$-states, $W_{coll}$, are enhanced by the factor $\sim 2 (\frac{\omega}{E})^{1/2}A^{1/3} \sim 10$ as compared to the single-particle value $w_{sp}$ what can result in values $|W_{coll}| \sim 20-30 eV$ if standard values of DDH parameters are used for $w_{sp}$. Similar enhancement arises in the P- and T-odd case.Comment: 15 pages, REVTEX 3, 2 figure

Anomalous anapole moment of an exotic nucleus

Using the information on the nuclear structure of exotic neutron-rich halo nucleus $^{11}$Be, we evaluate the parity violating anapole moment in its ground state. The resulting value $\kappa(^{11}$Be)$=0.17$ is fifteen times bigger than the typical value of the anapole moment of a normal nucleus of the same mass, and in fact exceeds by few times anapole moments of any known neutron-odd nuclei (e.g., kappa(^{11}Be) > 2|\kappa(^{207}Pb)|. It is also few times bigger than the neutral current contribution to the lepton-nucleus interaction.Comment: 12 pages, 2 figure

Problem of a quantum particle in a random potential on a line revisited

The density of states for a particle moving in a random potential with a Gaussian correlator is calculated exactly using the functional integral technique. It is achieved by expressing the functional degrees of freedom in terms of the spectral variables and the parameters of isospectral transformations of the potential. These transformations are given explicitly by the flows of the Korteweg-de Vries hierarchy which deform the potential leaving all its spectral properties invariant. Making use of conservation laws reduces the initial Feynman integral to a combination of quadratures which can be readily calculated. Different formulations of the problem are analyzed.Comment: 11 pages, RevTex, preprint ANU-RSPhySE-20994 (comment added

Limits of Time-Reversal Violating Interaction from Compound Nuclear Experiments

Mean square matrix elements of the time reversal invariance violating (TRIV) interaction between the compound nuclear states are calculated within the statistical model, using the explicit form of the TRIV interaction via the $\rho$-meson exchange. From the comparison of the calculated values with the data known for $p+ ^{27}Al \Leftrightarrow ^{24}Mg + \alpha$ reaction, and for $\gamma$-correlation measurements in $^{113}Cd(n,\gamma)^{114}Cd$ process, the bounds on the TRIV constant are obtained {\bar g}_{\rho} \alt 1.8 \times 10^{-2} and {\bar g}_{\rho} \alt 1.1 \times 10^{-2}. The sensitivity of the recently proposed detailed balance test experiments on isolated resonances in $^{32}S$ to the value of ${\bar g}_{\rho}$ is shown to be as high as to reach values ${\bar g}_{\rho} \sim 10^{-4}$.Comment: Phys. Lett. B; to be published, 16 pages, REVTEX 3, no figure