Assuming the existence of a gauge boson $X$ which couples to ${B-3L}_{\tau },$ we discuss the present experimental constraints on $g_X$ and $m_X$ from $\overrightarrow{Z}{l}^{+}{l}^{-}$ and $\overrightarrow{Z}\overline{f}fX(f=q,{\nu }_{\tau },\tau ).\mathrm{}$ We also discuss the discovery potential of $X$ at hadron colliders through its decay into ${\tau }^{+}{\tau }^{-}$ pairs. In the scenario where all three charged leptons (and their neutrinos) mix, lepton flavor nonconservation through $X$ becomes possible and provides another experimental probe into this hypothesis.

• Received 2 June 1998

DOI:https://doi.org/10.1103/PhysRevD.58.095005