Is Θ+(1540) a kaon–skyrmion resonance?

Itzhaki, Nissan; Klebanov, Igor R.; Ouyang, Peter; Rastelli, Leonardo

doi:10.1016/j.nuclphysb.2004.02.004

Cited by 102 publications

(176 citation statements)

References 48 publications

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“…Positive parity is supported by various model calculations, i.e., soliton models [2,5,10,11,12,41], chiral bag model [13], the Jaffe-Wilczek's diquark model [14], the Karliner-Lipkin's diquark-triquark model [15], some quark model calculations [16,17,18,19,20], and other model calculations [21,22]. Negative parity is supported by some other quark model calculations [3,4,23,24,25], and QCD sum rules [28].…”

Section: Introductionmentioning

confidence: 90%

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Pentaquark baryon in anisotropic lattice QCD

et al. 2005

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The penta-quark(5Q) baryon is studied in anisotropic quenched lattice QCD with renormalized anisotropy as/at=4 for a high-precision mass measurement. The standard Wilson action at β = 5.75 and the O(a) improved Wilson quark action with κ=0.1210(0.0010)0.1240 are employed on a 12 3 ×96 lattice. Contribution of excited states is suppressed by using a smeared source. We investigate both the positive-and negative-parity 5Q baryons with I = 0 and spin J = 1/2 using a non-NK-type interpolating field. After chiral extrapolation, the lowest positive-parity state is found to have a mass, mΘ = 2.25 GeV, which is much heavier than the experimentally observed Θ + (1540). The lowest negative-parity 5Q appears at mΘ = 1.75 GeV, which is near the s-wave NK threshold. To distinguish spatially-localized 5Q resonances from NK scattering states, we propose a new general method imposing a "Hybrid Boundary Condition (HBC)", where the NK threshold is artificially raised without affecting compact five-quark states. The study using the HBC method shows that the negative-parity state observed on the lattice is not a compact 5Q but an s-wave NK-scattering state.

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Section: Introductionmentioning

confidence: 90%

“…Numerous theoretical studies of penta-quark baryons have appeared since its discovery [5,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36]. One of the important issues is the spin and parity of Θ + .…”

Section: Introductionmentioning

confidence: 99%

Pentaquark baryon in anisotropic lattice QCD

et al. 2005

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“…Here an important issue is whether such nonstrange heavy pentaquark states are stable against strong decays [7,8,9,10,11]. Subsequent theoretical investigations on the Θ + include approaches based on the constituent quark model [12,13,14], Skyrme model [15,16,17,18,19], QCD sum rules [20,21], lattice QCD [22], chiral potential model [23], large N c QCD [24], and Group theory approach [25]. The production of the Θ + was also discussed in relativistic nuclear collisions [26], where the number of the anti-Θ + (1540) produced are expected to be similar to that of the Θ + (1540).…”

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confidence: 99%

Properties of the baryon antidecuplet

Kim

Lee

2004

Phys. Rev. D

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We study the group structure of baryon anti-decuplet containing the Θ + . We derive the SU(3) mass relations among the pentaquark baryons in the anti-decuplet, when there is either no mixing or ideal mixing with the pentaquark octet, as advocated by Jaffe and Wilczek. This constitutes the Gell-Mann-Okubo mass formula for the pentaquark baryons. We also derive SU(3) symmetric Lagrangian for the interactions of the baryons in the anti-decuplet with the meson octet and the baryon octet. Our analysis for the decay widths of the anti-decuplet states suggests that the N (1710) is ruled out as a pure anti-decuplet state, but it may have anti-decuplet component in its wavefunction if the multiplet is mixed with the pentaquark octet. The recent discovery of the Θ + baryon by LEPS Collaboration at SPring-8 [1], which has been confirmed by several groups [2], initiated a lot of theoretical works in the field of exotic hadrons. Experimentally, the Θ + is observed to have a mass of 1540 MeV and a decay width of < 25 MeV. Because of its positive strangeness, the Θ + baryon is exotic since its minimal quark content should be uudds. Other states that have positive strangeness but different charges are not observed, which suggests that the Θ + is an isosinglet. The existence of such an exotic state with narrow width was first predicted by Diakonov et al. [3] in the chiral soliton model, where the Θ + is a member of the baryon anti-decuplet. Although it should be confirmed by other experiments, the recently discovered Ξ −− 3/2 baryon [4] strongly supports the anti-decuplet nature of pentaquark baryons. The discussion on the existence of a baryon anti-decuplet has a longer history going back to the early 1970's [5], and in the Skyrme model [6]. Pentaquark states with a heavy antiquark (uuddc, uuddb) were also predicted in the Skyrme model. Here an important issue is whether such nonstrange heavy pentaquark states are stable against strong decays [7,8,9,10,11]. Subsequent theoretical investigations on the Θ + include approaches based on the constituent quark model [12,13,14], Skyrme model [15,16,17,18,19], QCD sum rules [20,21], lattice QCD [22], chiral potential model [23], large N c QCD [24], and Group theory approach [25]. The production of the Θ + was also discussed in relativistic nuclear collisions [26], where the number of the anti-Θ + (1540) produced are expected to be similar to that of the Θ + (1540).Several pressing issues that should be clarified are whether the Θ + has positive or negative parity, and whether the Roper N (1710) is included in the baryon anti-decuplet with the Θ + . As for the spin-parity of the Θ + , several works claim that J P = 1 2 − is more natural [13,21,22], which, however, is in contrast to the prediction of the soliton models, where the relative orbital angular momentum plays an important role 10

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“…Obviously, there is no agreement between (32) and (14)(15)(16)(17) for all 4 components of the "octet". Now, let us consider the "decuplet" of baryons, i.e.…”

Section: Nonexotic Baryon Statesmentioning

confidence: 99%

Baryon spectrum in largeNcchiral soliton and in quark models

Kopeliovich

Shunderuk

2006

Phys. Rev. D

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In memory of Karen Avetovich Ter-Martirosyan, the Teacher. IntroductionDescription of hadrons structure in terms of their quark constituents is generally accepted, but the alternative description within e.g. topological soliton (Skyrme) model [1,2] and its modifications also is useful and has certain advantages in comparison with traditional approaches. The chiral (topological) soliton approach is based on general principles and few ingredients incorporated in the effective chiral lagrangian, this is the reason for apparent simplifications in comparison, for example, with attempts to solve relativistic many-body problem. To simplify the latter, some additional objects like diquarks and triquarks have been phenomenologically introduced and discussed especially intensively after recent observations of the so called pentaquarks [3,4] 1 . Concept of diquarks "as an organizing principle for hadron spectroscopy" is considered in details in [12], see also [13]. The concepts of diquarks, triquarks or other correlated quark clusters are certainly of useful heuristic value, although their properties have not been deduced rigorously from basic QCD lagrangian. It should be noted that diquarks present in different physical states, baryons or mesons, can have different properties like the effective mass and size, even for same quantum numbers. 2In the present paper we perform explicit calculation of the strangeness contents of exotic and nonexotic baryon states at arbitrary number of colors N c , and discuss connection of the chiral soliton approach (CSA) and simple quark (pentaquark) model for exotic baryon states, 1 A contradictive present situation with experimental observation of possible pentaquark states is discussed, e.g. in [5,6]. Consideration of baryon states in the present paper is relevant independently on particular values of masses, widths and other properties of exotic baryon states measured experimentally. A detailed discussion of theoretical predictions of these states can be found in [7,8,9,10,11] 2 Some analogy with nuclei can be noted: two-, three-, etc. nucleon clusters play an important role in the structure of heavy nuclei, however, it is not possible to evaluate their properties from those of deuteron, helium etc., only. See, e.g. [14] for discussion of the role of femtometer toroidal structures in nuclei.

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Is Θ+(1540) a kaon–skyrmion resonance?

Cited by 102 publications

References 48 publications

Pentaquark baryon in anisotropic lattice QCD

Pentaquark baryon in anisotropic lattice QCD

Properties of the baryon antidecuplet

Baryon spectrum in largeNcchiral soliton and in quark models

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