How can we verify the weak selection rules of the new particles?

Abstract

Consequences of the weak selection rules for the new particles (charm, heavy leptons) are discussed for inclusive measurements. The quantities studied are ratios of mean numbers and of mean energies of ${\ensuremath{\pi}}^{+}$ versus ${\ensuremath{\pi}}^{\ensuremath{-}}$, ${\overline{K}}^{0}$ versus ${K}^{\ensuremath{-}}$, and ${K}^{0}$ versus ${K}^{+}$, both in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation and in $\ensuremath{\nu}$ and $\overline{\ensuremath{\nu}}$ rections. For ${e}^{+}{e}^{\ensuremath{-}}$ annihilation, we also give bounds on ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ energies in terms of the total energy available. The results hold with arbitrary cuts on $\ensuremath{\pi}$'s and $K$'s. Some results for ${e}^{+}{e}^{\ensuremath{-}}$ annihilation do not require full lepton detection, others do. For neutrino reactions, we also give bounds on the total number of kaons in terms of the number of observed ${K}_{S}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$. Special care is taken to fully include the complications arising from the isospin-violating decays ${D}^{*}\ensuremath{\rightarrow}D+\ensuremath{\pi}$ (or $\ensuremath{\gamma}$) and from the frequently occurring inseparability of production and decay mechanisms. Three main classes of events are considered, namely tagged decays in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation, single-fixed-sign-lepton production in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation, and prompt dilepton events in $\ensuremath{\nu}$ and $\overline{\ensuremath{\nu}}$ reactions.