Much Ado About Leptoquarks: A Comprehensive Analysis

摘要: We examine the phenomenological implications of a $\ensuremath{\sim}200\mathrm{GeV}$ leptoquark in light recent excess events at DESY HERA. Given relative predictions rates ${e}^{+}p$ versus ${e}^{\ensuremath{-}}p,$ we demonstrate that classes leptoquarks may be excluded, including those contained ${\mathrm{E}}_{6}$ grand unified theory (GUT) models. It is shown future studies with polarized beams HERA could reveal chirality fermionic coupling and given sufficient luminosity each ${e}_{L,R}^{\ifmmode\pm\else\textpm\fi{}}$ channel quantum numbers determined. The 200--220 GeV Fermilab Tevatron are examined. While present data most likely exclude vector leptogluons this mass region, it does allow for scalar leptoquarks. find while have little influence on Drell-Yan production, further Main Injector possible single production provided Yukawa couplings sufficiently large. investigate precision electroweak measurements as well process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}q\overline{q}$ CERN LEP II they provide no restrictions these then ascertain cross section polarization asymmetry Next Linear Collider (NLC) only direct mechanism to determine leptoquark's numbers. $\ensuremath{\gamma}e$ collisions by both back-scattered laser Weisacker-Williams techniques NLC also discussed. Finally, can obtain successful constant unification models leptoquarks, or without supersymmetry. supersymmetric case requires GUT group larger than SU(5) such flipped ${\mathrm{SU}(5)\ifmmode\times\else\texttimes\fi{}\mathrm{U}(1)}_{X}.$