The structure of superheavy elements newly discovered in the reaction of 86^{86}Kr with 208^{208}Pb

The structure of superheavy elements newly discovered in the $^{208}$Pb($^{86}$Kr,n) reaction at Berkeley is systematically studied in the Relativistic Mean Field (RMF) approach. It is shown that various usually employed RMF forces, which give fair description of normal stable nuclei, give quite different predictions for superheavy elements. Among the effective forces we tested, TM1 is found to be the good candidate to describe superheavy elements. The binding energies of the $^{293}$118 nucleus and its $\alpha-$decay daughter nuclei obtained using TM1 agree with those of FRDM within 2 MeV. Similar conclusion that TM1 is the good interaction is also drawn from the calculated binding energies for Pb isotopes with the Relativistic Continuum Hartree Bogoliubov (RCHB) theory. Using the pairing gaps obtained from RCHB, RMF calculations with pairing and deformation are carried out for the structure of superheavy elements. The binding energy, shape, single particle levels, and the Q values of the $\alpha-$decay $Q_{\alpha}$ are discussed, and it is shown that both pairing correlation and deformation are essential to properly understand the structure of superheavy elements. A good agreement is obtained with experimental data on $Q_{\alpha}$. %Especially, the atomic number %dependence of $Q_{\alpha}$ %seems to match with the experimental observationComment: 19 pages, 5 figure

Spherical Relativistic Hartree theory in a Woods-Saxon basis

The Woods-Saxon basis has been suggested to replace the widely used harmonic oscillator basis for solving the relativistic mean field (RMF) theory in order to generalize it to study exotic nuclei. As examples, relativistic Hartree theory is solved for spherical nuclei in a Woods-Saxon basis obtained by solving either the Schr\"odinger equation or the Dirac equation (labelled as SRHSWS and SRHDWS, respectively and SRHWS for both). In SRHDWS, the negative levels in the Dirac Sea must be properly included. The basis in SRHDWS could be smaller than that in SRHSWS which will simplify the deformed problem. The results from SRHWS are compared in detail with those from solving the spherical relativistic Hartree theory in the harmonic oscillator basis (SRHHO) and those in the coordinate space (SRHR). All of these approaches give identical nuclear properties such as total binding energies and root mean square radii for stable nuclei. For exotic nuclei, e.g., $^{72}$Ca, SRHWS satisfactorily reproduces the neutron density distribution from SRHR, while SRHHO fails. It is shown that the Woods-Saxon basis can be extended to more complicated situations for exotic nuclei where both deformation and pairing have to be taken into account.Comment: 12 pages, 9 figure

Spin-Hall effect with quantum group symmetry

We construct a model of spin-Hall effect on a noncommutative 4 sphere with isospin degrees of freedom (coming from a noncommutative instanton) and invariance under a quantum orthogonal group. The corresponding representation theory allows to explicitly diagonalize the Hamiltonian and construct the ground state; there are both integer and fractional excitations. Similar models exist on higher dimensional noncommutative spheres and noncommutative projective spaces.Comment: v2: 14 pages, latex. Several changes and additional material; two extra sections added. To appear in LMP. Dedicated to Rafael Sorkin with friendship and respec

Relativistic Hartree-Bogoliubov Approach for Nuclear Matter with Non-Linear Coupling Terms

We investigate the pairing property of nuclear matter with Relativistic Hartree-Bogoliubov(RHB) approach. Recently, the RHB approach has been widely applied to nuclear matter and finite nuclei. We have extended the RHB approach to be able to include non-linear coupling terms of mesons. In this paper we apply it to nuclear matter and observe the effect of non-linear terms on pairing gaps.Comment: 13 pages, 5 figure

General Relativistic Mean Field Theory for Rotating Nuclei

We formulate a general relativistic mean field theory for rotating nuclei starting from the special relativistic $\sigma - \omega$ model Lagrangian. The tetrad formalism is adopted to generalize the model to the accelerated frame.Comment: 13 pages, REVTeX, no figures, submitted to Phys. Rev. Lett., the word `curved' is replaced by `non-inertial' or `accelerated' in several places to clarify the physical situation interested, some references are added, more detail discussions are given with omitting some redundant sentence

New insight on pseudospin doublets in nuclei

The relevance of the pseudospin symmetry in nuclei is considered. New insight is obtained from looking at the continuous transition from a model satisfying the spin symmetry to another one satisfying the pseudospin symmetry. This study suggests that there are models allowing no missing single-particle states in this transition, contrary to what is usually advocated. It rather points out to an association of pseudospin partners different from the one usually assumed, together with a strong violation of the corresponding symmetry. A comparison with results obtained from some relativistic approaches is made.Comment: 27 pages, 18 figure

Microscopic Description of Super Heavy Nuclei

The results of extensive microscopic Relativistic Mean Field (RMF) calculations for the nuclei appearing in the alpha - decay chains of recently discovered superheavy elements with Z = 109 to 118 are presented and discussed. The calculated ground state properties like total binding energies, Q values, deformations, radii and densities closely agree with the corresponding experimental data, where available. The double folding (t-rho-rho) approximation is used to calculate the interaction potential between the daughter and the alpha, using RMF densities along with the density dependent nucleon - nucleon interaction (M3Y). This in turn, is employed within the WKB approximation to estimate the half lives without any additional parameter for alpha - decay. The half lives are highly sensitive to the Q values used and qualitatively agree with the corresponding experimental values. The use of experimental Q values in the WKB approximation improves the agreement with the experiment, indicating that the resulting interaction potential is reliable and can be used with confidence as the real part of the optical potential in other scattering and reaction processes.Comment: Accepted for publication in Annals of Physics (NY

Sensitivity of deexcitation energies of superdeformed secondary minima to the density dependence of symmetry energy with the relativistic mean-field theory

The relationship between deexcitation energies of superdeformed secondary minima relative to ground states and the density dependence of the symmetry energy is investigated for heavy nuclei using the relativistic mean field (RMF) model. It is shown that the deexcitation energies of superdeformed secondary minima are sensitive to differences in the symmetry energy that are mimicked by the isoscalar-isovector coupling included in the model. With deliberate investigations on a few Hg isotopes that have data of deexcitation energies, we find that the description for the deexcitation energies can be improved due to the softening of the symmetry energy. Further, we have investigated deexcitation energies of odd-odd heavy nuclei that are nearly independent of pairing correlations, and have discussed the possible extraction of the constraint on the density dependence of the symmetry energy with the measurement of deexcitation energies of these nuclei.Comment: 14 pages, 3 figure

News from the Muon (g-2) Experiment at BNL

The magnetic moment anomaly a_mu = (g_mu - 2) / 2 of the positive muon has been measured at the Brookhaven Alternating Gradient Synchrotron with an uncertainty of 0.7 ppm. The new result, based on data taken in 2000, agrees well with previous measurements. Standard Model evaluations currently differ from the experimental result by 1.6 to 3.0 standard deviations.Comment: Talk presented at RADCOR - Loops and Legs 2002, Kloster Banz, Germany, September 8-13 2002, to be published in Nuclear Physics B (Proc. Suppl.); 5 pages, 3 figure

Partial Wave Analysis of J/ψ→γ(K+K−π+π−)J/\psi \to \gamma (K^+K^-\pi^+\pi^-)

BES data on $J/\psi \to \gamma (K^+K^-\pi^+\pi^-)$ are presented. The $K^*\bar K^*$ contribution peaks strongly near threshold. It is fitted with a broad $0^{-+}$ resonance with mass $M = 1800 \pm 100$ MeV, width $\Gamma = 500 \pm 200$ MeV. A broad $2^{++}$ resonance peaking at 2020 MeV is also required with width $\sim 500$ MeV. There is further evidence for a $2^{-+}$ component peaking at 2.55 GeV. The non-$K^*\bar K^*$ contribution is close to phase space; it peaks at 2.6 GeV and is very different from $K^{*}\bar{K^{*}}$.Comment: 15 pages, 6 figures, 1 table, Submitted to PL