Anomalouseμevents ine+e−annihilation and heavy vector mesons

Abstract

As a possible explanation of the SLAC anomalous $e\ensuremath{\mu}$ events, we computed the cross section for ${e}^{+}+{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{V}^{+}+{V}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ifmmode\pm\else\textpm\fi{}}+{e}^{\ensuremath{\mp}}+\mathrm{neutrinos}$, taking into account the spin correlations of ${V}^{\ifmmode\pm\else\textpm\fi{}}$. Analytic formulas for the experimentally measured cross sections are given. The spin-correlation effects turn out to be small when ${V}^{\ifmmode\pm\else\textpm\fi{}}$ has vanishing anomalous magnetic moment ($\ensuremath{\kappa} = 0$), but are considerable for $\ensuremath{\kappa} \ensuremath{\approx} 1$. While the choice $\ensuremath{\kappa} = 0$ gives an unacceptable fit to the data, the choice $\ensuremath{\kappa} = 1$ improves the fit quite dramatically. The overall fit is still not good. However, we believe that the vector-meson model (with $\ensuremath{\kappa} \ensuremath{\approx} 1$) is not yet ruled out by the available data.