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Iowa State University

Elementary Particles and Fields and String Theory

1998

Articles 1 - 3 of 3

Full-Text Articles in Physics

Hadron Structures And Decays Within Quantum Chromodynamics , Alaa Abd El-Hady Jan 1998

Hadron Structures And Decays Within Quantum Chromodynamics , Alaa Abd El-Hady

Retrospective Theses and Dissertations

We have evaluated the meson spectrum using a relativistic model based on reductions of Bethe-Salpeter equation. We included one gluon exchange from Quantum Chromodynamics (QCD) and phenomenological confinement in the interaction kernel. We used an ansatz for the running of the coupling constant with the meson masses. We fitted more than forty states ranging from a hundred MeV to a few GeV using seven parameters, with root mean square deviation from experimental data of 40-50 MeV. This establishes our successful QCD-based model for many applications which we investigate;We employed our model to examine the strong interaction medium effects on ...


Ambiguities In The Definition Of Spin-Dependent Parton Distributions , Yuen-Wing Law Jan 1998

Ambiguities In The Definition Of Spin-Dependent Parton Distributions , Yuen-Wing Law

Retrospective Theses and Dissertations

We investigate the ambiguities in defining polarized parton distributions. We point out that in addition to the well-known renormalization scheme dependence in the unpolarized case, there are extra ambiguities in defining polarized parton distributions. These include the definition of [gamma]5 in d-dimension and interpretation of the anomalous contribution. Here, a new renormalization/factorization scheme called UV Subtraction (UVS) is proposed. In the new UVS scheme, it exploits the freedom in renormalization to eliminate the ambiguities arising from [gamma]5 and anomalous contribution. We also discuss the consequences of these ambiguities on the calculable short-distance partonic hard parts and corresponding ...


Flavor Changing Chronomagnetic Moments: A Monte Carlo Study Of The Top Quark , Matthias Danniel Hosch Jan 1998

Flavor Changing Chronomagnetic Moments: A Monte Carlo Study Of The Top Quark , Matthias Danniel Hosch

Retrospective Theses and Dissertations

We have studied direct top quark production and single top quark production through anomalous flavor changing chromomagnetic moments. We find that it is possible to detect anomalous flavor changing chromomagnetic moments of the top quark using direct top quark production if the charm quark coupling strength is larger than [kappa]c/[lambda]>.062 TeV-1 at Run 2 of the Tevatron, or larger than [kappa]c/[lambda]>.0084 TeV-1 at the LHC, or if the up quark coupling is larger than [kappa]u/[lambda]>.019 TeV-1 at the Tevatron or larger than [kappa]u/[lambda]>.0033 TeV-1 at the LHC. Single ...