Pseudo-spin as a relativistic symmetry

The existence of broken pseudo-spin symmetry in the Pb nucleus has been studied in the relativistic mean field approach using realistic Lagrangian parameters. Its relationship to spin orbit splitting and the vanishingly small surface delta character of the mean spin orbit potential are investigated. In the ²⁰⁸Pb nucleus the broken pseudo-spin doublets are found to exist above the neutron (proton) Fermi surfaces. Received: 16 April 1998 / Revised version: 26 June 1998     

Microscopic band-mixing calculations in154,156Gd

A many-body microscopic band-mixing formulation of variation after projection of angular momentum and conservation of nucleon number is used to study the yrast band and first excitedK ^π =0⁺ band in the doubly even nuclei^154,156Gd. The computed energy spectra and the interband and intra-band B (E2) values are in good agreement with corresponding experimental data. Connection with the phenomenological model of Stephens and Simon is discussed, bringing out the role played by thei _13/2 neutron pair in the microscopic formalism.     

Energy moments of scattering phase shift for partly non-local momentum dependent interaction

The phase shift sum rules recently derived by Puff are extended for a general partly non-local momentum dependent potential. In achieving this, one must use Fredholm determinant of the outgoing solution of the Schrodinger equation instead of the Jost function as was done by Puff. The constants appearing in the moment relations are explicitly defined in terms of the momentum representation of the interaction.     

Semiclassical analysis of α-transfer reactions

Semiclassical concepts are used to gain insight into α-transfer reactions. These reactions, interpreted as one-step direct reactions on the basis of DWBA analyses, are treated in analogy with single nucleon transfer reactions for which it is known that semiclassical methods are successful. In this case however the probability of transfer appears to be greatest at a distance of closest approach which is larger than the grazing distance by the order of the α-particle radius. This increase in the effective “grazing” distance is interpreted as a manifestation of the α-particle size at the time of transfer. Angular distributions are calculated semiclassically for the reactions ²⁰⁸Pb(¹⁶O, ¹²C)²¹²Po at 93 MeV and ⁴⁰Ca(¹²C, ⁸Be)⁴⁴Ti at 45 MeV lab energy. They are seen to give a reasonable fit to experiment. Partial wave amplitudes for transfer are also studied.     

Numerical investigation of the stagnation point flow of radiative magnetomicropolar liquid past a heated porous stretching sheet

Journal of Thermal Analysis and Calorimetry - In this paper, we have investigated the two-dimensional magnetohydrodynamic steady boundary layer flow of a viscous magnetomicropolar liquid via an...     

Core polarization effects and the random phase approximation solution

A metricg _ik=η _ik+Hξ _iξ_k+2Jξ _(iPk) is investigated. WhenJ=0 this reduces to the well-known Kerr metric. Conditions on the vectorp _i are obtained under which a geodetic, shear-free null congruenceξ _i in the Minkowskian space-time (with metricη _ik) will continue to remain geodetic and shear-free in the Riemannian space-time ofg _ik. A general solution of Einstein’s equationR _ik=σξ _iξ_k is obtained whenp _iξⁱ=0 andξ _i is twist-free.     

Schwinger’s effective lagrangian from reflection and transmission amplitudes

The reflection and transmission amplitudes are defined from the asymptotic form of the solution of Dirac equation of a charged fermion in the presence of uniform time independent external electromagnetic field (E, H). Schwinger’s effective lagrangian is derived from the reflection and transmission amplitudes. It is found that both the real and imaginary parts of the effective lagrangian agree with Schwinger’s expressions derived from the elegant method of proper time formalism.     

Microscopic theory of soliton propagation in4He films

A microscopic theory has been provided for propagation of solitons in superfluid⁴He films at temperatureT=0°K.     

Isobaric degrees of freedom in nuclei as determined from nonrelativistic quark model

Isobaric degrees of freedom δδ in nuclei are determined from the quark cluster model of a nucleus. These additional degrees of freedom are brought in by the coloured quark exchange between different nucleon clusters present in nuclei. They are found to be important in the region of momentum transfer near 3.5 fm⁻¹. The mass dependence of these isobaric degrees of freedom in nuclei turns out to beA ^5/6.