120520180
Finite electron self-mass in a nonperturbative iterative scheme of quantum electrodynamics
Abstract We show that the electron self-mass δm is finite and equal to electron mass m in the recently proposed nonperturbative iterative scheme of quantum electrodynamics. This has to be contrasted with the logarithmically divergent expression which is obtained in second order perturbation theory.
120097279
Thirring fermions at high temperature
A Green's-function method is used to study the thermodynamic properties of self-interacting massless dimension and one time dimension. It is shown that the exact expression can be obtained for the thermodynamic one-particle Green's function for the case where the dimensionless chemical potential $mu$ = 0, which is identical with the corresponding field-theoretic Green's function. The number density is obtained as an infinite sum. It exhibits a peculiar peaked behavior as a function of momentum. The energy, however, is a continuous function of temperature. (AIP)
21885814
Measurable decay modes of barium isotopes via exotic cluster emissions.
Cluster decays of $^{112\mathrm{\ensuremath{-}}120}\mathrm{Ba}$ nuclei are calculated within a preformed cluster model. The \ensuremath{\alpha}-nuclei $^{4}\mathrm{He}$, $^{8}\mathrm{Be}$, $^{12}\mathrm{C}$, $^{16}\mathrm{O}$, and $^{20}\mathrm{Ne}$ are predicted as the possible decay modes, lying within the limits of present experimental methods. Other than the \ensuremath{\alpha} particle, $^{12}\mathrm{C}$ decay of $^{112}\mathrm{Ba}$ is shown to be the most probable one with half-life time ${\mathit{T}}_{1/2}$\ensuremath{\sim}${10}^{4}$ s, stressing the role of doubly magic $_{50}^{100}\mathrm{Sn}$ daughter nucleus in cluster radioactivity. The use of different Q values for ${\mathit{T}}_{1/2}$ estimates and presence of nuclear structure effects in Geiger-Nuttall plots are also discussed.
120879756
Neck formation and deformation effects in a preformed cluster model of exotic cluster decays
Using the nuclear proximity approach and the two center nuclear shape parametrization, the interaction potential between two deformed and pole-to-pole oriented nuclei forming a necked configuration in the overlap region is calculated and its role is studied for the cluster decay half-lives. The barrier is found to move to a larger relative separation, with its proximity minimum lying in the neighborhood of the Q value of decay and its height and width reduced considerably. For cluster decay calculations in the preformed cluster model of Malik and Gupta, due to deformations and orientations of nuclei, the (empirical) preformation factor is found to get reduced considerably and agrees nicely with other model calculations known to be successful for their predictions of cluster decay half-lives. Comparison with the earlier case of nuclei treated as spheres suggests that the effects of both deformations and neck formation get compensated by choosing the position of cluster preformation and the inner classical turning point for penetrability calculations at the touching configuration of spherical nuclei. {copyright} {ital 1997} {ital The American Physical Society}
123091744
Supercurrent Anomaly in the Framework of Analytic Regularization
122510459
Exact Bianchi Type-I Cosmological Models in a Scalar-Tensor Theory
Abstract
In this paper, a spatially homogeneous and anisotropic Bianchi type-I space-time filled with perfect fluid is investigated within the framework of a scalar-tensor theory proposed by Saez and Ballester. Two different physically viable models of the universe are obtained by using a special law of variation for Hubble’s parameter that yields a constant value of deceleration parameter. One of the models is found to generalize a model recently investigated by Reddy et al. (Astrophys. Space Sci. 306:171, 2006). The Einstein’s field equations are solved exactly and the solutions are found to be consistent with the recent observations of type Ia supernovae. A detailed study of physical and kinematical properties of the models is carried out.

118299250
Intermediate Mass Fragment Production In Symmetric Collisions
We present a complete systematic theoretical study of multifragmentation and its associated phenomena in heavy ion collisions. This study is performed within an Isospin dependent Quantum Molecular Dynamical Model (IQMD) and using Minimum Spanning Tree (MST) algorithm. Simulations are carried out to study the different parameters like time evolution of multiplicity, mass distribution, impact parameter dependence and IMF's production dependence of projectile & target mass. The rise and fall in multiplicity of IMF's is observed. Results are compared with experimental data of ALADIN and are found to be in close agreement.
118619694
On nuclear stopping in asymmetric colliding nuclei
Abstract Using the isospin-dependent quantum molecular dynamics (IQMD) model, nuclear stopping is analyzed in asymmetric colliding channels by keeping the total reacting mass fixed. The calculations have been performed by varying the mass asymmetry of the colliding pairs with different neutron–proton ratios at an incident beam energy of 250 MeV/nucleon. We find sizable effects of mass asymmetry on nuclear stopping and on the equilibrium of the nuclear matter. A reasonable agreement is also observed between the experimental data and our present calculations.
122678585
Importance of momentum dependent interactions in multifragmentation
15856484
Geometric construction of elliptic integrable systems and N=1* superpotentials
We show how the elliptic Calogero-Moser integrable systems arise from a symplectic quotient construction, generalising the construction for A_{N-1} by Gorsky and Nekrasov to other algebras. This clarifies the role of (twisted) affine Kac-Moody algebras in elliptic Calogero-Moser systems and allows for a natural geometric construction of Lax operators for these systems. We elaborate on the connection of the associated Hamiltonians to superpotentials for N=1* deformations of N=4 supersymmetric gauge theory, and argue how non-perturbative physics generates the elliptic superpotentials. We also discuss the relevance of these systems and the associated quotient construction to open problems in string theory. In an appendix, we use the theory of orbit algebras to show the systematics behind the folding procedures for these integrable models.