Reviewing the Evidence for Pentaquarks

Abstract

Several experimental groups have reported evidence for baryons with flavor exotic quantum numbers that cannot be explained as $qqq$ bound states but require a minimum of five quarks -- $qqqq\bar{q}$. These pentaquark states include the ${\theta }^{+}$, the ${\Xi }^{--}$ and the ${\theta }_c$. The reported widths of these new states are consistent with experimental resolution and may be as narrow as a few MeV/$c^2$ or less. Prior to 2003, experimental searches for flavor exotic baryons spanning several decades yielded negative results. There have also been a number of searches carried out since the reports of these new pentaquark states that do not confirm their existence. This review of both the positive and negative reports seeks to understand the current situation regarding the experimental evidence for pentaquarks.

arXiv commentTalk presented by A. R. Dzierba at the First Meeting of the APS Topical Group on Hadronic Physics, October, 2004

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Cited by in corpus (17)

• Non-Standard Heavy Mesons and Baryons, an Experimental Review
• The Physics of the B Factories
• Baryon spectroscopy
• Search for the ${\Theta }^{+}$ pentaquark in the reaction $\gamma d\to p{K}^{-}{K}^{+}n$
• The Hadronic Final State at HERA
• Exotic Tetraquark ud bar[s] bar[s] of J^P=0^+ in the QCD Sum Rule
• Pentaquark Theta^+(1540) production in gamma N --> K Anti-K N
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• Colour Fields of the Static Pentaquark System Computed in SU(3) Lattice QCD
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• XYZ States: Theory Overview
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• Low-lying ud anti-s anti-s configurations in a non-relativistic constituent quark model
• New Particles from Belle
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• Theoretical Overview: The New Mesons
• Looking for pentaquarks in Lattice QCD