No Arabic abstract
The idea of a strongly interacting sector as responsible for the electroweak symmetry breaking is tested through an effective lagrangian description, called the BESS model, constructed on the standing point of custodial symmetry and gauge invariance, without specifing any dynamical scheme.
Supernovae of type Ia (SNe Ia) are very important for cosmography. To exclude systematic effects in linking the observed light of distant SNe Ia to the parameters of cosmological models, one has to understand the nature of supernova outbursts and to build accurate algorithms for predicting their emission. We review the recent progress of modeling the propagation of nuclear flame subject to numerous hydrodynamic instabilities inherent to the flame front. The Rayleigh-Taylor (RT) instability is the main process governing the corrugation of the front on the largest scales, while on the smallest scales the front propagation is controlled by the Landau-Darrieus instability. Based on several hydrodynamic explosion models, we predict the broad-band UBVI and bolometric light curves of SNe Ia, using our 1D-hydro code which models multi-group time-dependent non-equilibrium radiative transfer inside SN ejecta. We employ our new corrected treatment for line opacity in the expanding medium, which is important especially in UV and IR bands. The results are compared with the observed light curves. Especially interesting is a recent 3D-deflagration model computed at MPA, Garching, by M. Reinecke et al.
In this talk I discuss some recent developments in physics beyond the Standard Model. After some initial comments on neutrino masses, I discuss the status of low-energy supersymmetry and finally turn to describing some recent work in theories with extra spatial dimensions. Plenary talk at the XIX International Symposium on Lepton and Photon Interactions at High Energies, Stanford University, 9-14 August 1999.
In this talk, we describe recent developments in the Skyrme model. Our main focus is on discussing various effects which need to be taken into account, when calculating the properties of light atomic nuclei in the Skyrme model. We argue that an important step is to understand spinning Skyrmions and discuss the theory of relative equilibria in this context.
We consider the continuum limit of a moose model corresponding to a generalization to N sites of the Degenerate BESS model. The five dimensional formulation emerging in this limit is a realization of a RS1 type model with SU(2)_L x SU(2)_R in the bulk, broken by boundary conditions and a vacuum expectation value on the infrared brane. A low energy effective Lagrangian is derived by means of the holographic technique and corresponding bounds on the model parameters are obtained.
We review recent developments in the type IIB matrix model, which was conjectured to be a nonperturbative formulation of superstring theory. In the first part we review the recent results for the Euclidean model, which suggest that SO(10) symmetry is spontaneously broken. In the second part we review the recent results for the Lorentzian model. In particular, we discuss Monte Carlo results, which suggest that (3+1)-dimensional expanding universe emerges dynamically. We also discuss some results suggesting the emergence of exponential expansion and the power-law expansion at later times. The behaviors at much later times are studied by the classical equation of motion. We discuss a solution representing 3d expanding space, which suggests a possible solution to the cosmological constant problem.