Particle Spectrum of the Supersymmetric Standard Model from the Massless Excitations of a Four Dimensional Superstring

A superstring action is quantised with Neveu Schwarz(NS) and Ramond(R) boundary conditions. The zero mass states of the NS sector are classified as the vector gluons, W-mesons, $B_{\mu}$-mesons and scalars containing Higgs. The fifteen zero mass fermions are obtained from the Ramond sector. A space time supersymmetric Hamiltonian of the Standard Model is presented without any conventional SUSY particles

The Prediction of Mass of Z'-Boson from bq0−bq0barb_q^0-b_q^0 bar Mixing

B_q^0-B_^0 bar mixing offers a profound probe into the effects of new physics beyond the Standard Model. In this paper, $B_s^0-B_s^0 bar$ and $B_d^0-B_d^0 bar$ mass differences are considered taking the effect of both Z-and Z' -mediated flavour-changing neutral currents in the $B_q^0-B_q^0 bar$ mixing (q = d, s). Our estimated mass of Z' boson is accessible at the experiments LHC and B-factories in near future.Comment: 11 pages, 02 Figure

Phase Transition and Hybrid Star in a Nonlinear σ−ω\sigma - \omega model

The phase transition between the nuclear matter and the quark matter is examined. The relativistic mean field theory(RMF) is consider with interacting nucleons and mesons using TM1 parameter set for the nuclear matter equations of state. It is found that the trasition point depends on coupling constant $\alpha_s$ and bag pressure. From the study of the structure of a hybrid neutron star, it is observed that the star contains quark matter in the interior and neutron matter on the outer perifery.Comment: 8 pages, 7 figures, to appear in Int. J. Mod. Phy.

The Wess-Zumino term and quantum tunneling

The significance of the Wess--Zumino term in spin tunneling is explored, and a formula is established for the splitting of energy levels of a particle with large fermionic spin as an applied magnetic field is switched on.Comment: Latex, 7 page

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