The Z -> bb decay asymmetry and flavor changing neutral currents
Abstract
The measured value of A_b, the Z \bar bb asymmetry parameter, disagrees with the Standard Model at 99% confidence level. If genuine the discrepancy could indicate new interactions unique to third generation quarks, implying enhanced Z penguin amplitudes. Enhanced rates are predicted for rare K and B decays, such as K^{+} --> pi^{+}\bar nu nu, K_{L} --> pi^{0}\bar nu nu, B --> X_{s}\bar nu nu, and B_{s} --> \bar mu mu. Measurements of epsilon^{\prime}/epsilon then imply QCD penguin amplitudes must also be similarly enhanced. The Higgs sector of an SU(2)_L x SU(2)_R gauge theory has some of the features needed to explain these phenomena and would also imply right-handed penguin amplitudes.
Keywords
Cite
@article{arxiv.hep-ph/9905478,
title = {The Z -> bb decay asymmetry and flavor changing neutral currents},
author = {Michael S. Chanowitz},
journal= {arXiv preprint arXiv:hep-ph/9905478},
year = {2007}
}
Comments
10 pages, 1 figure. Revision includes additional predictions for rare K and B decays with new treatment of errors, additional references, some other changes in presentation