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Recent Results on Searches for Pentaquark States from STAR at RHIC

Huan Z. Huang
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Abstract

We present results on pentaquark searches from nuclear collisions at RHIC with the STAR detector system. An intriguing peak has been observed in the invariant mass distribution of $pK^{+}+\overline{p}K^{-}$ from 18.6 Million d+Au collision events at $\sqrt{s_{_{NN}}} = 200$~GeV. The peak centers at a mass $1528 \pm 2 \pm 5$~MeV/c$^{2}$ and the FWHM $\sim15$ MeV/c$^{2}$ limited by detector responses. The statistical significance of the peak is $4.2σ$. Such a state if confirmed is manifestly exotic and implies a family of isospin one states. A weak signal of less statistical significance ($\sim3σ$) has been observed in 5.6M Au+Au collision events at 62.4 GeV. Searches in 10.7M Au+Au collision events at 200 GeV yield no significant signal. The Au+Au results neither confirm nor rule out the d+Au observation as a possible state.

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Huan Z. Huang. 2005-09-30. Recent Results on Searches for Pentaquark States from STAR at RHIC. https://doi.org/10.1142/s0217751x06032101

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