Related papers: R_b Problem: Loop Contributions and Supersymmetry
We compute the supersymmetric contribution to $R_{b}\equiv \Gamma (Z\to b{\bar b})/\Gamma (Z\to {\rm hadrons})$ in a variety of supersymmetric models. In the context of supergravity models with universal soft-supersymmetry-breaking and…
A previous study of supersymmetric models has indicated that they are unlikely to make a large contribution to R_b. We revisit this analysis, taking into account the improved lower limits on sparticle masses provided recently by LEP 2 and…
In the last few years, much progress has been made in the computation of one-loop virtual matrix elements for processes involving many external particles. In this contribution the methods that have enabled this recent progress are briefly…
We discuss one-loop contributions of supersymmetry (SUSY) particles to the process $e^+e^- \to W^+W^-$ in the minimal supersymmetric standard model. The calculation is tested by using the sum rule among the form factors, which is based on…
We perform the complete computation of the contributions to $b\to s+\gamma, b\to s e^{+}e^{-}, b\to s\sum \nu_{i} \bar{\nu}_{i}$ in supersymmetric model with bilinear R-parity violation. We compare our calculations with the evaluations in…
We study the correlation of quantum effects on the ratios R_b and R_c within the framework of the MSSM. While in the SM the quantity R_b is in discrepancy with experiment at the 2 \sigma level from below, and R_c differs from the…
In this talk I summarize a part of the work done in a recent collaboration with C. Burgess, J. Cline, D. London and E. Nardi \cite{b96}. We analyze the observed discrepancy between $R_b(\equiv\gb /\ghad )$ as measured at LEP and its…
In the framework of the Littlest Higgs Model with T-parity (LHT), we study the contributions of the new particles to $Zb\bar{b}$ couplings at one-loop level. Based on these results, we further study the branching ratio $R_{b}$ and the…
This article provides a brief overview of some of the theoretical aspects of R-parity violation (RPV) in the minimal supersymmetric standard model (MSSM) and its extensions. Both spontaneous and explicit RPV models are discussed and some…
We re-examine the possible magnitude of the supersymmetric contribution to $R_b\equiv\Gamma(Z^0\to\bar b b)/\Gamma(Z^0\to{\rm all})$ in the light of the constraints imposed by the absence of light charginos at LEP~1.5, implementing also…
We have found the possible region of parameters of the minimal supersymmetric standard model (MSSM) within the bounds from the experimental results of the Higgs mass, the rare decay mode of $b$-quark, the muon $g-2$, the dark matter…
We present a pedagogical introduction to supersymmetry and supersymmetric models and give an overview of the potential of the linear collider for studying them. If supersymmetry is found, its discovery will bring with it many more questions…
In this paper I review the multiplet calculus of $N = 1$, $D = 1$ local supersymmetry with applications to the construction of models for spinning particles in background fields, and models with space-time supersymmetry. New features…
We construct a specific formalism for calculating the one-loop virtual corrections for standard model processes with an arbitrary number of external legs. The procedure explicitly separates the infrared and ultraviolet divergences…
We introduce a new technique for solving uni-parametric versions of linear programs, convex quadratic programs, and linear complementarity problems in which a single parameter is permitted to be present in any of the input data. We…
The class of relativistic spin particle models reveals the `quantization' of parameters already at the classical level. The special parameter values emerge if one requires the maximality of classical global continuous symmetries. The same…
We compute the one-loop corrections to the $Z \to b\bar{b}$ vertex in the $U(1)_R$ symmetric minimal supersymmetric extension of the standard model. We find that the predicted value of $R_b$ is consistent with experiment if the mass of the…
We study integrals over Hermitian supermatrices of arbitrary size $p+q$, that are parametrized by an external field $X$ and a source $Y$, of respective size $m+n$ and $p+q$. We show that these integrals exhibit a simple topological…
Superfields provide a compact description of supersymmetry representations. Loop corrections with superfield formalism are simpler and much more manageable than calculation in terms of component fields. In this paper we calculate the…
Systems of equations are invariant under "polydimensional transformations" which reshuffle the geometry such that what is a line or a plane is dependent upon the frame of reference. This leads us to propose an extension of Clifford calculus…