Cosmic Evolution in Generalised Brans-Dicke Theory

We have studied the Generalised Brans-Dicke theory and obtained exact solutions of a(t),phi(t),and omega(t) for different epochs of the cosmic evolution .We discuss how inflation,decceleration,cosmic acceleration can result from this solution.The time variation of G(t) is also examined.Comment: 12 pages, no figure

Application of Relativistic Coupled-cluster Theory to Electron Impact Excitations of Mg+^+ in the Plasma Environment

A relativistic coupled-cluster (RCC) theory is implemented to study electron impact excitations of atomic species. As a test case, the electron impact excitations of the $3s ~ ^2S_{1/2} - 3p ~ ^2P_{1/2;3/2}$ resonance transitions are investigated in the singly charged magnesium (Mg$^+$) ion using this theory. Accuracies of wave functions of Mg$^+$ are justified by evaluating its attachment energies of the relevant states and compared with the experimental values. The continuum wave function of the projectile electron are obtained by solving Dirac equations assuming distortion potential as static potential of the ground state of Mg$^+$. Comparison of the calculated electron impact excitation differential and total cross-sections with the available measurements are found to be in very good agreements at various incident electron energies. Further, calculations are carried out in the plasma environment in the Debye H\"uckel model framework, which could be useful in the astrophysics. Influence of plasma strength on the cross-sections as well as linear polarization of the photon emission in the $3p ~ ^2P_{3/2} - 3s ~ ^2S_{1/2}$ transition is investigated for different incident electron energies.Comment: 9 pages, 1 table and 3 figure

Gravitational Waves in Generalised Brans-Dicke Theory

We have solved cosmological gravitational Wave(GW)equation in the frame work of Generalised Brans-Dicke(GBD) theory for all epochs of the Universe.The solutions are expressed in terms of the present value of the Brans-Dicke coupling parameter $\omega(\phi)$.It is seen that the solutions represent travelling growing modes for negative values of $\omega_{0}$ for all epochs of the Universe.Comment: 7Pages,no figure

Effect of both Z and Z'-mediated flavor-changing neutral currents on the baryonic rare decay lambdablambda_b decays into lambdal+l−lambda l^+l^-

We study the effect of both Z and Z'-mediated flavor-changing neutral currents (FCNCs) on the $lambda_b arrow lambda l^+l^- (l = mu, tau)$ rare decay. We find the branching ratio is reasonably enhanced from its standard model value due to the effect of both Z and Z'-mediated FCNCs, and gives the possibility of new physics beyond the standard model. The contribution of Z'-boson depends upon the precise value of the mass of Z' boson.Comment: 14 page

Melting and Casting of Non-ferrous Metals and Alloys

In general sense, a casting is produced when molten metal is poured into a mould and left to cool and solidify. The other name given to a casting is 'Founding'. In casting process, metal/ alloy component parts of desired shapes are produced by pouring the molten metal/alloy into a prepared mould (of that shape) and then allowing the molten metal/alloy to cool and solidify. This solidified piece of metal/alloy is known as a casting