Saswati Sarkar

CONSTRAINTS ON THE SU(5)C × SU(2)L × U(1)′ MODEL FROM LEP DATA

We have determined constraints on the SU(5)C × SU(2)L × U(1)′ model in terms of the extra mixing angle ϕ in the neutral gauge boson sector and ΔρM, the deviation of the Standard Model ρ parameter from unity at the tree level, using the recent precision measurements at LEP on electroweak parameters at the Z peak. The lower bound of the extra Z′ boson mass has also been determined.

INTERMEDIATE AND HIGH ENERGY BEHAVIOR OF THE SU(5)C MODEL

We have shown that the SU(5)C model cannot be distinguished from the Standard Model by measuring the spin-averaged cross-section and forward-backward asymmetry parameters in the processes near the Z peak and in the nonresonant sector. However, the e+e−→μ+μ− process can distinguish the SU(5)C model from the Standard Model in the nonresonant sector at the level of 2σ effect when MZ is around 100 GeV.

Off-shell t-matrix for an exponential potential with non-local core interaction

Abstract The wave function approach of Van Leeuwen and Reiner to the t -matrix is generalized to the case of a non-local potential. The transition matrix element for this potential is obtained. The results are used to compute the s-wave part of the t -matrix for a non-local square well potential combined with an outside exponential potential.

SU(2)L×U(1)Y×S3×Dmodel for atmospheric and solar neutrino deficits

Motivated by the recent Super-Kamiokande experiment on atmospheric and solar neutrino oscillation we propose a see-saw model of three generations of neutrinos based on the gauge group

An

SU(2)_{L}\times U(1)_{Y}

SU(2)_{L}\times U(1)_{Y} \times S_{3} \times D

with discrete symmetries

model for atmospheric and solar neutrino deficits

(S_{3} \times D)

An SU(2)(L) x U(1)(Y) x S(3) x D model for atmospheric and solar neutrino deficits

and three right handed singlet neutrinos so that this model can accommodate the recent Super-Kamiokande data on atmospheric and solar neutrino oscillations. The model predicts maximal mixing between

SPONTANEOUS CP VIOLATION IN A TWO GENERATION SU(2)L × SU(2)R × U(1)B − L × U(1)H MODEL

\nu_{\mu}

SPONTANEOUS CP VIOLATION IN A TWO-GENERATION LEFT-RIGHT SYMMETRIC MODEL WITH TWO HIGGS BI-DOUBLETS

and