84,469 research outputs found

    Multiple Chirality in Nuclear Rotation: A Microscopic View

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    Covariant density functional theory and three-dimensional tilted axis cranking are used to investigate multiple chirality in nuclear rotation for the first time in a fully self-consistent and microscopic way. Two distinct sets of chiral solutions with negative and positive parities, respectively, are found in the nucleus 106Rh. The negative-parity solutions reproduce well the corresponding experimental spectrum as well as the B(M1)/B(E2) ratios of the transition strengths. This indicates that a predicted positive-parity chiral band should also exist. Therefore, it provides a further strong hint that multiple chirality is realized in nuclei.Comment: 15 pages, 5 figures, 1 tabl

    Is the CMB asymmetry due to the kinematic dipole?

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    Parity violation found in the Cosmic Microwave Background (CMB) radiation is a crucial clue for the non-standard cosmological model or the possible contamination of various foreground residuals and/or calibration of the CMB data sets. In this paper, we study the directional properties of the CMB parity asymmetry by excluding the m=0m=0 modes in the definition of parity parameters. We find that the preferred directions of the parity parameters coincide with the CMB kinematic dipole, which implies that the CMB parity asymmetry may be connected with the possible contamination of the residual dipole component. We also find that such tendency is not only localized at l=2,3l=2,3, but in the extended multipole ranges up to l22l\sim 22.Comment: 17 pages, 5 figures, 2 tables, improved version, ApJ accepte

    Impact of pairing correlations on the orientation of the nuclear

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    For the first time, the tilted axis cranking covariant density functional theory with pairing correlations has been formulated and implemented in a fully self-consistent and microscopic way to investigate the evolution of the spin axis and the pairing effects in rotating triaxial nuclei. The measured energy spectrum and transition probabilities for the Nd-135 yrast band are reproduced well without any ad hoc renormalization factors when pairing effects are taken into account. A transition from collective to chiral rotation has been demonstrated. It is found that pairing correlations introduce additional admixtures in the single-particle orbitals, and, thus, influence the structure of tilted axis rotating nuclei by reducing the magnitude of the proton and neutron angular momenta while merging their direction.Comment: 13 pages, 5 figure

    New parametrization for the nuclear covariant energy density functional with point-coupling interaction

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    A new parametrization PC-PK1 for the nuclear covariant energy density functional with nonlinear point-coupling interaction is proposed by fitting to observables for 60 selected spherical nuclei, including the binding energies, charge radii and empirical pairing gaps. The success of PC-PK1 is illustrated in its description for infinite nuclear matter and finite nuclei including the ground-state and low-lying excited states. Particularly, PC-PK1 improves the description for isospin dependence of binding energy along either the isotopic or the isotonic chains, which makes it more reliable for application in exotic nuclei. The predictive power of PC-PK1 is also illustrated for the nuclear low-lying excitation states in a five-dimensional collective Hamiltonian in which the parameters are determined by constrained calculations for triaxial shapes.Comment: 32 pages, 12 figures, 4 tables, accepted by Phys. Rev.