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Theta++ from QCD sum rule

Tetsuo Nishikawa·Yoshiko Kanada-En'yo·Osamu Morimatsu·Yoshihiko Kondo
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Abstract

We study the pentaquark $uudd\bar s$ with $J=3/2$ and I=1 ($Θ^{++}$) in the QCD sum rule approach. We derive the QCD sum rules for positive and negative parity states of the pentaquark. The QCD sum rule predicts that there exists $Θ^{++}$ with negative parity and its mass is $1.5\sim1.6$ GeV. The negative parity $Θ^{++}$ can be extremely narrow, since it lies much below the $ΔK$ threshold and the decay into $KN$ state is strongly suppressed due to the $D$-wave centrifugal barrier. Also, the possibility of the existence of the $Θ^{++}$ with positive parity is not excluded. Although it nearly degenerates with the negative parity state, it may be broader than the negative parity state.

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Tetsuo Nishikawa, Yoshiko Kanada-En'yo, Osamu Morimatsu, Yoshihiko Kondo. 2004-11-09. Theta++ from QCD sum rule. https://doi.org/10.1103/physrevd.71.016001

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