Measurement of the Resonance Parameters of the $χ_{1}(1^3P_1)$ and $χ_{2}(1^3P_2)$ States of Charmonium formed in Antiproton-Proton Annihilations
Abstract
Description
We have studied the $^3P_J$ ($χ_c)$ states of charmonium in formation by antiproton-proton annihilations in experiment E835 at the Fermilab Antiproton Source. We report new measurements of the mass, width, and $B(χ_{cJ} \to \bar{p} p) \times Γ(χ_{cJ} \to J/ψ+ anything)$ for the $χ_{c1}$ and $χ_{c2}$ by means of the inclusive reaction $\bar{p}p \to χ_{cJ}
\to J/ψ+ anything \to (e^{+}e^{-}) +anything $. Using the subsample of events where $χ_{cJ} \to γ+ J/ψ\to γ+ (e^{+}e^{-}) $ is fully reconstructed, we derive $B(χ_{cJ} \to \bar p p)\times Γ(χ_{cJ} \to J/ψ+ γ) $. We summarize the results of the E760 (updated) and E835 measurements of mass, width and $ B(χ_{cJ} \to \bar{p}p) Γ(χ_{cJ} \to J/ψ+γ)$ (J=0,1,2) and discuss the significance of these measurements.