Study of the $χ_{c 0} (1 {}^{3}P_{0})$ State of Charmonium Formed in $\bar{p} p$ Annihilations

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11 October 1999

journal article
research article
Published by American Physical Society (APS) in Physical Review Letters

Vol. 83 (15) , 2902-2905
https://doi.org/10.1103/physrevlett.83.2902

Abstract

The resonance parameters of

χ_{c 0}

, the

{}^{3}{1 P}_{0}

resonance of charmonium, have been measured at the Fermilab Antiproton Accumulator by means of the reaction

\bar{p} p \to χ_{c 0} \to γ J / ψ \to γ (e^{+} e^{-})

. The results are

M (χ_{c 0}) {= 3417.4}_{- 1.9}^{+ 1.8} \pm 0.2 MeV {/ c}^{2}

,

Γ (χ_{c 0}) {= 16.6}_{- 3.7}^{+ 5.2} \pm 0.1 MeV

, and

Γ (χ_{c 0} \to \bar{p} p) \times B (χ_{c 0} \to J / ψ γ) \times B (J / ψ \to e^{+} e^{-}) {= 2.89}_{- 0.53}^{+ 0.67} \pm 0.14 eV

. Using known branching ratios we also obtain

Γ (χ_{c 0} \to \bar{p} p) {= 8.0}_{- 1.5 - 1.9}^{+ 1.9 + 3.5} keV

. These results are discussed in relation to the other

χ_{cJ}

states and to theoretical predictions.

Keywords

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