arXiv subjects
Publications and source records attributed to Hatem Widyan.
Scalar field theory with asymmetric potential is studied for $ϕ^4$ theory with $ϕ^3$ symmetry breaking. The equations of motion are solved analytically up to the second order to get the bounce-solution.
The false vacuum decay in field theory from a coherently oscillating initial state is studied for $ϕ^6$ potential. An oscillating bubble solution is obtained. The instantaneous bubble nucleation rate is calculated.
The 'tHooft-Polyakov monopole is treated as constrained system using the Hamilton-Jacobi method. The set of the Hamilton-Jacobi partial differential equations and the equations of motion are obtained. The quantization of the system is also discussed.
Scalar field theory with an asymmetric potential is studied at zero temperature and high-temperature for $ϕ^6$ potential. The equations of motion are solved numerically to obtain O(4) spherical symmetric and O(3) cylindrical symmetric bounce solutions. These solutions control the rates for tunneling from the false vacuum to the true vacuum by bubble formation. The range of validity of the thin-wall approximation (TWA) is investigated. An analytical solution for the bounce is presented, which reproduces the action in the thin-wall as well as the thick-wall limits.
The temperature dependance of the action in the thin-wall and thick-wall limits is obtained analytically for the $ϕ^6$ scalar potential. The nature of the phase transition is investigated from the quantum tunnelling regime at low temperatures to the thermal hopping regime at high temperatures. It is first-order for the case of a thin wall while for the thick wall it is second- order.
A scenario based on the TopFlavor model is presented to explain the origin of a light sterile neutrino as indicated by all combined neutrino oscillation experiments. The model is phenomenologically well motivated and compatible with all available low-energy data. The derived nuetrino mass matrix can qualitatively explain the observed hierarchy in the neutrino mass splittings as indicated by the neutrino oscillation data. Numerical results are obtained for special cases.
The nature of the transition from the quantum tunneling regime at low temperatures to the thermal hopping regime at high temperatures is investigated analytically in scalar field theory. An analytical bounce solution is presented, which reproduces the action in the thin-wall as well as thick-wall limits. The transition is first order for the case of a thin wall while for the thick wall case it is second order.
It is shown that the minimal left-right symmetric model admits cosmic string and domain wall solutions. The cosmic strings arise when the SU(2)_R is broken and can either be destabilized at the electroweak scale or remain stable through the subsequent breakdown to U(1)_{EM}. The strings carry zero modes of the neutrino fields. Two distinct domain wall configurations exist above the electroweak phase transition and disappear after that. Thier destablization provides new sources of non-equilibrium effects below the electroweak scale which is relevant to baryogenesis.
The nature of the transition from quantum tunneling at low temperatures to thermal hopping at high temperatures is investigated in a scalar field theory with cubic symmetry breaking. The bounce solution which interpolates between the zero-temperature and high-temperature solutions is obtained numerically, using a multigrid method. It is found that, for a small value of the symmetry-breaking coupling f, the transition is first-order. For higher values of f, the transition continues to be first-order, though weakly so.
Scalar field theory with an asymmetric potential is studied at zero temperature and high-temperature for phi^4 theory with both phi and phi^3 symmetry breaking. The equations of motion are solved numerically to obtain O(4) symmetric and O(3) cylindrical symmetric bounce solutions. These solutions control the rates for tunneling from the false vacuum to the true vacuum by bubble formation. The range of validity of the thin-wall approximation (TWA) is investigated. An analytical solution for the bounce is presented, which reproduces the action in the thin-wall as well as the thick-wall limits.
It is shown that the minimal Left-Right symmetric model admits cosmic string, domain wall and conditionally, monopole solutions. The strings arise when the $SU(2)_R$ is broken and can either be destabilized at the electroweak scale or remain stable through the subsequent breakdown to $U(1)_{EM}$. The monopoles and domain wall configurations exist in the $SU(2)_L\otimes U(1)_Y$ symmetric phase and disappear after subsequent symmetry breaking. Their destabilization provides new sources of non-equilibrium effects below the electroweak scale. Several defect-mediated mechanisms for low energy baryogenesis are shown to be realisable in this model.