Nuclear potential energy surfo:>,ces a~ a functlcin of cleforma:tions are calculated on the basis of a nt)dified osclll.at.or model. In particular, quadrupole (P 2) and hexadecupole (P 1) deformation;; nrc • considered. The average behavior of the sur_face is norrr:a.lized to that ofu liquid drop through 'the employment of a gei1eraliz.ed Strutinski prescription. In this way a synthesi:; of the slnglc particle model and the liquid drop model is obtained. Lowest minima. in the potential energy surfaces give the ~rounc~ state masses ond distortions. These results compare extremely well wi.th experimental data. Spontaneous fission half lives are obtained. 'l'he inertial parameters as::wcia ted with fission barrier pcnetn:ttlon are derived empidcally as well as by a microscopic modeL Sh::tpe (fisslon) isomeric states _o.re also found. Thelr N and Z dependence in the present model are discusccd and results tabulated. The calculations arc extended to the predicted nuperbea.vy region around Z :: 111~ nnd N == 18/1. 1'he total overall stnh:U.i ty ~rith respect to alpha L-tnd beta. decay, and Epontaneous fission fs fou .. "ld to be most favorable in the vic:!n.Uy of b:::: 110 and N = J.8IL Detailed diagrams and tables arc exhibited.

The coupled ηN , πN , γN , ππN system is described by a K-matrix method. The parameters in this model are adjusted to get an optimal fit to πN → πN , πN → ηN , γN → πN and γN → ηN data in an energy range of about 100 MeV or so each side of the η-threshold. Compared with our earlier analysis, we now utilize recent Crystal Ball data. However, the outcome confirms our previous result that the η-nucleon scattering length (a) is large with a value of 0.91(6)+i0.27(2) fm.PACS numbers: 13.75.-n, 25.80.-e, 25.40.V

The nuclear periphery was studied by using antiprotons. Two experimental methods were applied: analysis of the antiproton annihilation residues one mass unit lighter than the target mass by nuclear spectroscopy and the measurement of strong interaction effects on antiprotonic level widths and shifts. 26 isotopes from a wide range of mass numbers (40<A<238) were investigated. The gathered antiprotonic-atom data were compared with the results obtained using hadron scattering methods and with some expectations from theoretical approaches.

The coupled N,N system is described by a K-matrix method. The parameters in this model are adjusted to get an optimal fit to N→N, N→N, and ␥N→N data in an energy range of about 100 MeV each side of the threshold. In the notation T Ϫ1 ϩiq ϭ1/aϩ ͑r 0 /2͒ q 2 ϩsq 4 , q being the momentum in the N center of mass, the resulting effective range parameters for N scattering are found to be a ͑fm͒ ϭ0.75͑4͒ϩi0.27 (3), r 0 ͑fm͒ ϭ-1.50͑13͒Ϫi0.24͑4͒, and s ͑fm 3 ) ϭ-0.10͑2͒Ϫi0.01͑1͒. ͓S0556-2813͑97͒50705-9͔ PACS number͑s͒: 13.75.Gx, 25.80.Ϫe, 25.40.VeThe pion-nucleon and pion-nucleus interactions have been much studied, both theoretically and experimentally, for many years. However, the corresponding interactions of the meson, mainly because of the lack of -beams, have-by comparison-been neglected. The main interest in 's has been the possibility of -nuclear quasibound states. Such states were first predicted by Haider and Liu ͓1͔ and Li et al.͓2͔, when it was realized that the -nucleon interaction was attractive. Calculations by Ueda indicated ͓3͔ that this may *Electronic

Using multiple scattering theory the scattering lengths of η mesons on helium nuclei are calculated and checked against final state η interactions from the pd → η 3 He and dd → η 4 He reactions. The existence of an η 4 He quasibound state is indicated.

We report on an updated Paris NN optical potential. The long-and intermediate-range real parts are obtained by G-parity transformation of the Paris N N potential based on a theoretical dispersionrelation treatment of the correlated and uncorrelated two-pion exchange. The short-range imaginary potential parametrization results from the calculation of the NN annihilation box diagram into two mesons with a nucleon-antinucleon intermediate state in the crossed channel. The parametrized real and imaginary short range parts are determined by fitting not only the existing experimental data included in the 1999 version of the Paris NN potential, but also the recent antiprotonic-hydrogen data andnp total cross sections. The description of these new observables is improved. Only this readjusted potential generates an isospin zero 1 S0, 52 MeV broad quasibound state at 4.8 MeV below the threshold. Recent BES data on J/ψ decays could support the existence of such a state.

We derive a closed, model independent, expression for the electromagnetic correction factor to a phenomenological hadronic scattering length a h extracted from a hydrogenic atom. It is obtained in a non-relativistic approach and in the limit of a short ranged hadronic interaction to terms of order α 2 log α using an extended charge distribution. A hadronic πN scattering length a h π − p = 0.0870 (5)m −1 π is deduced leading to a πNN coupling constant from the GMO relation g 2 c /(4π) = 14.04 (17).

UCRL-18068We have attempted to predict spontaneous-fission half lives of a series of isotopes with Z values near the closed shell proton number Z :::: 114 1,2,3) and neutron number N near 184.The calculations lend some support to speculations that an island of relatively long lived elements may be expected for nuclei with Z near 114 and N near 184.The shell model field on which this study is based is effectively that suggested by Gustafson et al. in ref. 3), and given here in eq. (5). The corresponding level scheme in the sperical case is exhibited in figs. la and lb. A careful determination of the parameters of the potential in the rare earth deformed region and in the actinide region exists, and from these regions a brave and linear extrapolation of the potential parameters is made to It has been found earlier that a summation of single-particle energies based on the potential (5), or its predecessor, subject to the condition of conservation of equipotential volumes and with appropriate correction for Coulomb and pairing effects, gives good predictions for the relatively small equilibrium distortions. 5 ,6) However, the same procedure fails at large distortions. Thus the 12term,or the p4 term, treated within only one N shell,is found to simulate a surface-energy term only at small distortions. 7 )To overcome this deficiency of the nuclear potential a normalization procedure due to StrutinSky8) has been applied. Accordihg to Strutinsky's prescription one first defines a smoothed reference level dens;ity g(e) by averaging the calculated single-particle levels and where (2) We have used the value ~ ~ 0.8 bW O (E,E4). The term (2) is inserted to correct for errors introduced by the folding procedure.8 ,11) Based on this smoothed level density a corresponding average energy is calculated aswhere ~ is determined separately for neutrons and protons so as to meet the requirement of given neutron and proton numbers.This background energy, given by eq. (3), is later to be replaced by the liquid drop energy. Shell and pairing corrections, till be added later to the liquid drop energy,are calculated with reference to this background energy as §This sum is to be evaluated separately for neutrons and protons. In eq. (4) 2 2 the quantities e are the single-particle energies, and V and U are the v v v corresponding pairing theory population factors. The strength G in eq. (4) of the pairing interaction is taken to be (19.6/A) MeV and (14/A) MeV for protons and neutrons respectively, e~ploying N neutron and Z proton levels.'fhe adequacy 'of this prescription over a larger mass region is presently being investigated. The term G~l represents the subtracted diagonal pairing corresponding to a sharp Fermi surface.Finally, the total potential energy of deformation, constructed according to the above prescriptions, is given by § E=E +E l+Eh l+E . surf cou s el palrAs reported in ref.3) the single-particle energies have been calculated for the potential -5- UCRL-18068 Since at the present time only r~trix elements within each N sh...