Search for exclusive B decays to J and η or π⁰ with the L3 detector

Abstract

A search for exclusive decays of B_d⁰ and B_s⁰ mesons has been performed in the channels B_d⁰ → J_η, B_s⁰ → J_η, B_d⁰ → J_π⁰ and B_s⁰ → J_π⁰. The data sample consisted of more than three and half million hadrozic Z decays collected by the L3 experiment at LEP from 1991 through 1995. No candidate events have been observed for any of the modes thus determining upper limits at 90% confidence level: 3.2 × 10−4 on Br(B_d⁰ → J_π⁰) and the first experimental limits: Br(B_d⁰ → J_η) < 1.2 × 10⁻³, Br(B_s⁰ → J_η) < 3.8 × 10⁻³, Br(B_s⁰ → J_π⁰) < 1.2 × 10⁻³.