Meson-Nucleon Vertex Form Factors at Finite Temperature Using a Soft Pion Form Factor

The temperature and density dependence of the meson-nucleon vertex form factors is studied in the framework of thermofield dynamics. Results are obtained for two rather different nucleon-nucleon potentials: the usual Bonn potential and the variation with a softer $\pi NN$ form factor, due to Holinde and Thomas. In general, the results show only a modest degree of sensitivity to the choice of interaction.Comment: 5 pages, uses revtex

Massive scalar field instability in Kerr spacetime

We study the Klein-Gordon equation for a massive scalar field in Kerr spacetime in the time-domain. We demonstrate that under conditions of super-radiance, the scalar field becomes unstable and its amplitude grows without bound. We also estimate the growth rate of this instability.Comment: 10 pages, 5 figure

A test of the instanton vacuum chiral quark model with axial anomaly low-energy theorems

The QCD + QED axial anomaly low-energy theorems are applied to estimate the accuracy of an instanton vacuum - based chiral quark model. The low-energy theorems give an exact relation between the matrix elements of the gluon and photon parts of the QCD + QED axial anomaly operator equation. The matrix elements between vacuum and two photon states and between vacuum and two gluon states are calculated for arbitrary N_f. It is shown that this model does satisfy the low-energy theorems with an accuracy of $\sim 17$. We estimate also the contribution of the nonperturbative conversion of gluons into photons to the decay $\eta ' \rightarrow 2 \gamma$ and compare with experimental data.Comment: uudecode, gzip, latex, 11 pages, the text and the list of references was slightly change

Development of Sintered Iron Driving Bands

The present investigation reports some detailed studies carried out on the development testing and proving of sintered Iron Driving Bands. Sintering studies on two different types of iron powders together with a few Fe-Cu compositions have been made and based on the results there of, parameters for development iron driving bands have been standardised. The results obtained clearly demonstrate that substitution of copper by sintered iron is highly practicable alternative

First-principles study of the onset of noncollinearity in Mnn clusters: Magnetic arrangements in Mn5 and Mn6

First-principles theoretical investigations of the noncollinearity of atomic spin moments in manganese clusters have been carried out within a gradient-corrected density-functional approach. Our studies on Mn5 and Mn6 include investigation of both collinear and noncollinear arrangements. It is shown that while the atomic structure of the ground state of Mn5 is a triangular bipyramid, the collinear and noncollinear arrangements have comparable energies and hence are degenerate. For Mn6, while the ground state has a square bipyramid arrangement, the noncollinear configuration is most stable making it the smallest cluster to feature a noncollinear ground state. The results are discussed in view of the recent experimental Stern-Gerlach profiles