<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>Θ</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow><mml:mn /><mml:mo>(</mml:mo><mml:mn>1540</mml:mn><mml:mo>)</mml:mo><mml:mn /></mml:math>as a heptaquark with the overlap of a pion, a kaon, and a nucleon

Bicudo, Pedro; Marques, Gonçalo M.

doi:10.1103/physrevd.69.011503

Cited by 57 publications

(59 citation statements)

References 34 publications

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“…[4] it was reported to be even less than 1 MeV. Several mechanisms have been proposed to explain this narrow width: the strongly correlated diquark model [28,29], the πKN bound state picture [30,31,32], the possible isospin I = 2 quantum number [33] and the possibility of two nearly degenerate pentaquarks [34]. Even though all these propositions may be able to explain some properties of Θ + , they are not yet completely satisfactory.…”

Section: Introductionmentioning

confidence: 99%

Spin-3/2 Pentaquark in QCD Sum Rules

Gubler

Oka

Kojo

et al. 2009

Strangeness in Nuclear and Hadronic Systems

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The QCD sum rule method is formulated for the strangeness +1 pentaquark baryon with isospin I = 0 and spin-parity J π = 3 2± . The spin-states are considered to be narrower than the spin-1 2 ones, and thus may provide a natural explanation for the experimentally observed narrow width of Θ + . In order to obtain reliable results in QCD sum rule calculations, we stress the importance of establishing a wide Borel window, where convergence of the operator product expansion and sufficient low-mass strength of the spectral function are guaranteed. To this end, we employ the difference of two independent correlators so that the high-energy continuum contribution is suppressed. The stability of the physical quantities against the Borel mass is confirmed within the Borel window. It is found that the sum rule gives positive evidence for the (I, J π ) = (0,

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Section: Introductionmentioning

confidence: 99%

Spin-3/2 Pentaquark in QCD Sum Rules

Gubler

Oka

Kojo

et al. 2009

Strangeness in Nuclear and Hadronic Systems

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“…Bicudo proposed an interesting alternate scheme for Θ + baryon [68]. Using the resonating group method, he found that the repulsion is increased by Pauli principle whenever the two interacting hadrons have a common flavor quark.…”

Section: F Heptaquarksmentioning

confidence: 99%

Pentaquarks

Zhu

2004

Int. J. Mod. Phys. A

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Since LEPS collaboration reported the first evidence of Θ + pentaquark in early 2003, eleven other experimental groups have confirmed this exotic state while many other groups didn't see any signal. If this state is further established by future high statistical experiments, its discovery shall be one of the most important events in hadron physics for the past three decades. This exotic baryon with such a low mass and so narrow a width imposes a big challenge to hadron theorists. Up to now, there have appeared more than two hundred theoretical papers trying to interpret this charming state. I will review some important theoretical developments on pentaquarks based on my biased personal views.

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“…The next logical possibility is to consider a quasibound state of KπN, which in s-wave would naturally correspond to spin-parity 1/2 + , the quantum numbers suggested in [5]. Such an idea has already been put forward in [18] where a study of the interaction of the three body system is conducted in the context of chiral quark models, which suggests that it is not easy to bind the system although one cannot rule it out completely. A more detailed work is done in [19], which we summarize here.…”

Section: Introductionmentioning

confidence: 99%