We discuss leptonic mixing and CP violation at low and high energies, emphasizing possible connections between leptogenesis and CP violation at low energies, in the context of lepton flavour models. Furthermore we analyse weak basis invariants relevant for leptogenesis and for CP violation at low energies. These invariants have the advantage of providing a simple test of the CP properties of an...

A parameterized model of the mass distribution within the Milky Way is fitted to the available observational constraints. Constraints at R < R0 and at R ≃ R0 are well satisfied, while those at 1 < R/R0 <∼ 2 cannot be adequately fitted with the consequence that the circular speed vc(R) at R > R0 is extremely uncertain. The most important single parameter is the ratio of the scale length Rd,∗ of ...

There has been intense research interest in phase transitions in mass-transport and growth models involving adsorption and desorption, fragmentation, diffusion, and aggregation. These processes are ubiquitous in nature and arise in a large number of seemingly diverse systems such as growing interfaces [1,2], colloidal suspensions [3], polymer gels [4], river networks [5], granular materials [6]...

Numerical simulations are performed on different lattice sizes of chiral U(1) and SU(2) scalar-fermion models with explicit mirror pairs of fermions in the broken symmetry phase. Relevance of these models to the electroweak theory is discussed. Shift symmetry of the action is exploited to decouple the unwanted mirror-fermion. Upper and lower bounds on the renormalized scalar mass as a function ...

We have previously reported the discovery of strong gravitational lensing by faint elliptical galaxies using the WFPC2 on HST and here we investigate their potential usefulness in putting constraints on lens mass models. We compare various ellipsoidal surface mass distributions, including those with and without a core radius, as well as models in which the mass distributions are assumed to have...

In the ellipsoidal collapse model, the critical density for the collapse of a gravitationally bound object is a function of its mass. In the excursion set formalism, this translates into a moving barrier problem such that the mass function of dark matter haloes is given by the first crossing probability of a random walker across the barrier. In this paper, we study this first crossing probabili...

We study left-right symmetric quark mass matrices whose upand down-sectors have the same structure. This type of realistic mass matrices are derived from orbifold models. Alexander von Humboldt Fellow e-mail: [email protected] The origin of the fermion masses is one of the most important problems in particle physics. Higher dimension couplings could explain the hier...

There are two basic theoretical approaches to obtaining neutrino mass and mixing. In the minimalist approach, one adds just enough new stuff to the Minimal Standard Model to get mν 6= 0 and Uαi 6= 1. In the holistic approach, one uses a general framework or principle to enlarge the Minimal Standard Model such that, among other things, mν 6= 0 and Uαi 6= 1. In both cases, there are important sid...

I discuss the problem of generation mass hierarchy in the context of realistic superstring models which are constructed in the free fermionic formulation. These models correspond to models which are compactified on Z2 × Z2 orbifold. I suggest that the hierarchy among the generations results from horizontal symmetries, which arise from the compactification. In particular, I show that in a class ...

We present a comparison between two observational and three theoretical mass functions for eight cosmological models suggested by the data from recently completed BOOMERANG-98, MAXIMA-1 cosmic microwave background (CMB) anisotropy experiments as well as peculiar velocities (PV) and Type Ia Supernovae (SN) observations. The cosmological models have been proposed as the best fit models by several...