相关论文: Conformality and Gauge Coupling Unification
We investigate the prospects to achieve unification of the gauge couplings in models without supersymmetry. We restrict our discussion to $SU(5), SO(10)$ and $E_6$ models that mimic the structure of the Standard Model as much as possible…
We consider the conformal gauging of non-abelian groups. In such cases there are inequivalent ways of gauging (generalizing the axial and vector cases for abelian groups) corresponding to external automorphisms of the group. Different…
The evolution of Standard Model gauge couplings is studied in a non-supersymmetric scenario in which the hierarchy problem is resolved by Higgs compositeness above the weak scale. It is argued that massiveness of the top quark combined with…
We discuss the low energy implications of gauge coupling unification at the string scale, taking into account string threshold corrections in the $SU(4) {\times} O(4)$ model. We express $sin^2\theta_W$ and $a_3$ as functions of the…
We explore possibilities of gauge coupling unification in left--right symmetric models with non--minimal particle content. In addition to unification we require the absence of anomalies and sufficient proton lifetime. Numerous previously…
We consider a recent proposal by Dimopoulos and Kaplan to embed the electroweak SU(2)_L X U(1)_Y into a larger group SU(3)_W X SU(2) X U(1) at a scale above a TeV. This idea is motivated by the prediction for the weak mixing angle sin^2…
A realistic SU(3)_C x SU(3)_W unified theory is constructed with a TeV sized extra dimension compactified on the orbifold S_1/Z_2, leaving only the standard model gauge group SU(3)_C x SU(2)_L x U(1)_Y unbroken in the low energy 4D theory.…
The measured values of two electroweak gauge couplings appear to obey an approximate 5% SU(3) relation. Unless this is an accident caused by fortuitous Planck-scale physics, it suggests the presence of an SU(3) symmetry near the electroweak…
The apparent unification of gauge couplings around 10^16 GeV is one of the strong arguments in favor of Supersymmetric extensions of the Standard Model (SM). In this contribution a new analysis, using the latest experimental data, is…
The global chiral symmetry of a $SU(2)$ gauge theory is studied in the framework of renormalization group (RG). The theory is defined by the RG flow equations in the infrared cutoff $\L$ and the boundary conditions for the relevant…
Old folklore says that there is no non-trivial renormalization group fixed point with $U(1)$ gauge symmetry in four dimensions, but it can be circumvented by the existence of magnetic monopoles. We propose to construct (potentially…
The possibility of achieving a gauge coupling grand unification by increasing the QCD degrees of freedom at higher energies is investigated. When confronted with precision low-energy data, the generic weak-mixing angle relation…
We examine gauge and Yukawa coupling unification in models with gauge-mediated supersymmetry breaking. We work consistently to two-loop order, and include all weak, messenger and unification-scale threshold corrections. We find that…
The purpose of this paper is threefold: a) Check if the rather poor Standard Model (SM) fit to all electroweak data can be improved in its minimal supersymmetric extension (MSSM); b) Check what constraints present electroweak data has on…
In this article I describe the recently-conjectured field-string duality which suggests a class of nonsupersymmetric gauge theories which are conformal (CGT) to leading order of 1/N and some of which may be conformal for finite N. If the…
Higher dimensional grand unified theories, with gauge symmetry breaking by orbifold compactification, possess SU(5) breaking at fixed points, and do not automatically lead to tree-level gauge coupling unification. A new framework is…
Effective theories with the matter content of the minimal supersymmetric Standard Model below the string scale M_string predict a wrong value for the weak--mixing angle sin^2\theta_W and strong coupling constant \alpha_S at the scale M_Z.…
We have studied the gauge unification with the recent electroweak data as a function of the higgsino mass. It was shown that if the strong coupling constant is small $\approx 0.11$, consistent picture of gauge unification is not possible in…
We study dynamical electroweak symmetry breaking with a fourth generation within the $Z_n$ orbifolded $AdS_5\otimes S^5$ framework. A realistic $Z_7$ example is discussed. The initial theory reduces dynamically, due to the induced…
We present new results for the SU(3) "sextet model" with two flavors transforming according to the two-index symmetric representation of the gauge group. The simulations are performed using unimproved Wilson fermions. We measure the meson…