Observation of a Resonance X(1835) in J/{psi}{yields}{gamma}{pi}{sup +}{pi}{sup -}{eta}{sup '}

Journal Article · Sat Dec 31 04:00:00 EST 2005 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.95.262001· OSTI ID:20771635

Ablikim, M; Bai, J Z; Bian, J G; Cai, X; Chen, H S; Chen, H X; Chen, J C; Jin, Chen; Chen, Y B; Chu, Y P; Cui, X Z; Deng, Z Y; Dong, L Y; Du, S X; Du, Z Z; Fang, J; Fu, C D; Gao, C S; Gu, S D; Guo, Y N ^[1]

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1. Institute of High Energy Physics, Beijing 100049 (China)

The decay channel J/{psi}{yields}{gamma}{pi}{sup +}{pi}{sup -}{eta}{sup '} is analyzed using a sample of 5.8x10{sup 7} J/{psi} events collected with the BESII detector. A resonance, the X(1835), is observed in the {pi}{sup +}{pi}{sup -}{eta}{sup '} invariant-mass spectrum with a statistical significance of 7.7{sigma}. A fit with a Breit-Wigner function yields a mass M=1833.7{+-}6.1(stat){+-}2.7(syst) MeV/c{sup 2}, a width {gamma}=67.7{+-}20.3(stat){+-}7.7(syst) MeV/c{sup 2}, and a product branching fraction B(J/{psi}{yields}{gamma}X){center_dot}B(X{yields}{pi}{sup +}{pi}{sup -}{eta}{sup '})=[2.2{+-}0.4(stat){+-}0.4(syst)]x10{sup -4}. The mass and width of the X(1835) are not compatible with any known meson resonance. Its properties are consistent with expectations for the state that produces the strong pp mass threshold enhancement observed in the J/{psi}{yields}{gamma}pp process at BESII.

• OSTI ID: 20771635
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 26 Vol. 95; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

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