g-2 in composite models of leptons

Based on the bound state description of the muon and general relativistic covariant quantum field theory, we illustrate with a simple composite model that the observed deviation of (g-2)_\mu can be a demonstration of the substructure of the muon and give the constraints on the radius of the muon in different cases of light constituents and heavy constituents.Comment: 14 pages, 4 eps figures, revtex, several arguments and some references renewe

Twist-3 contribution to the pion electromagnetic form factor

Non-leading contribution to the pion electromagnetic form factor which comes from the pion twist-3 wave function is analyzed in the modified hard scattering approach (MHSA) proposed by Li and Sterman. This contribution is enhanced significantly due to bound state effect (the twist-3 wave function is independent of the fractional momentum carried by the parton and has a large factor $\sim m_\pi^2/m_0$ with $m_\pi$ being the pion meson mass and $m_0$ being the mean u- and d-quark masses). Consequently, although it is suppressed by the factor $1/Q^2$, the twist-3 contribution is comparable with and even larger than the leading twist (twist-2) contribution at intermediate energy region of $Q^2$ being $2 \sim 40 {GeV}^2$.Comment: 10 pages, 2 fgures, latex. More discussions on the Sudakov effect added, references added. To appear in European Physical Journal C (Zeitschrift fur Physik C

THE EFFECTS OF ESTIMATION ERROR IN PORTFOLIO CREDIT RISK MODELING

In this paper, we assess the effects of estimation error due to the impact of noisy input parameters in portfolio credit risk modelling by using Monte-Carlo simulations. We employ the methodology used in L?ffler (2003) but apply different dataset to form two new portfolios: obligors with investment-grade credit rating and obligors with speculative-grade credit rating. The four sources of estimation risk are considered for each portfolio: default rate uncertainty only, recovery rate uncertainty only, correlation uncertainty only, and the three sources of uncertainty together. The resulting estimation error in the distribution of portfolio losses is considerable. The paper also shows that different credit datasets could result in different biases in value at risk (VaR) estimations in each portfolio

B→Xsτ+τ−B \to X_{s} \tau^{+} \tau^{-} in the flipped SU(5) model

We perform a detailed study of the inclusive branching ratio and the forward-backward asymmetry of the rare B decay process $B \longrightarrow X_{s} \tau^{+} \tau^{-}$ in the flipped SU(5) model, a predictive model which has only two free parameters, plus the sign of the higgs mixing mass $\mu$, to describe mass spectrum and mixings of about 30 sparticles. In contrast to other works dealing with such a topic, our study has included the contributions of the neutral higgs bosons through penguin diagrams to this process under the context of supersymmetry. In some regions of the parameter space, due to the substantial enhancement effects coming from supersymmetry, these contributions become quite significant and could make the flavor change process $B \longrightarrow X_{s} \tau^{+} \tau^{-}$ a microscope to probe the regions of large tan$\beta$ and a window to gain an insight into new physics beyond the standard model(SM).Comment: 10 pages, 2 figure

Numerical simulation and analysis of the mechanical behaviour of cable supported glass facades

This thesis aims to contribute to the evolution of structural glass technologies by presenting an analysis of a façade prototype and intends to provide insight on the mechanical behaviour of these systems