EVIDENCE OF S = +1 NARROW RESONANCES IN THE SYSTEM $K_s^0 p$

Aslanyan, P. Zh.; Emel′yanenko, Vladimir N.; Rikhkvitzkaya, G. G.

doi:10.1142/9789812701909_0116

Cited by 15 publications

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“…In this letter, the exercise of determining the wave function of five interacting constituent quarks in the flavor-exotic multiquark hadronic sector is solved using the variational Monte Carlo (VMC) technique. This technique is known to yield upper bounds on the ground state energy accurate to the level of a few percent in light nuclei with the number of nucleons A ≤ 6 [1].Recent experimental evidence [2,3,4,5,6,7,8,9,10,11,12,13] has revived interest in the multiquark flavorexotic sector of the hadronic spectrum. Various model calculations have been reported [14,15,16,17,18,19,20,21,22,23] which study the existence of a strangeness S = +1 resonance, dubbed θ + , about 100 MeV above threshold to nucleon-kaon decay with low mass of 1540(2) MeV and possibly extremely narrow width of 0.9(3) MeV [24].…”

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confidence: 99%

Variational Monte Carlo Study of Pentaquark States

Paris

2005

Phys. Rev. Lett.

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Accurate numerical solution of the five-body Schrödinger equation is effected via variational Monte Carlo. The spectrum is assumed to exhibit a narrow resonance with strangeness S = +1. A fully antisymmetrized and pair-correlated five-quark wave function is obtained for the assumed nonrelativistic Hamiltonian which has spin, isospin, and color dependent pair interactions and manybody confining terms which are fixed by the non-exotic spectra. Gauge field dynamics are modeled via flux tube exchange factors. The energy determined for the ground states with J π = 1 2 − ( 1 2 + ) is 2.22 GeV (2.50 GeV). A lower energy negative parity state is consistent with recent lattice results. The short-range structure of the state is analyzed via its diquark content.A system of interacting, non-relativistic constituent quarks is the most simple, realistic model of hadronic systems. Solving the many-body Schrödinger equation to determine wave functions within this simple model is still a formidable task owing to the strong flavor, spin, and color dependence of the quark-quark interaction and traditionally requires some array of approximate methods to solve it. The controversial status of the recent evidence of a flavor exotic five-quark state warrants a careful treatment of this strongly interacting system. In this letter, the exercise of determining the wave function of five interacting constituent quarks in the flavor-exotic multiquark hadronic sector is solved using the variational Monte Carlo (VMC) technique. This technique is known to yield upper bounds on the ground state energy accurate to the level of a few percent in light nuclei with the number of nucleons A ≤ 6 [1].Recent experimental evidence [2,3,4,5,6,7,8,9,10,11,12,13] has revived interest in the multiquark flavorexotic sector of the hadronic spectrum. Various model calculations have been reported [14,15,16,17,18,19,20,21,22,23] which study the existence of a strangeness S = +1 resonance, dubbed θ + , about 100 MeV above threshold to nucleon-kaon decay with low mass of 1540(2) MeV and possibly extremely narrow width of 0.9(3) MeV [24]. Lattice results are available, including Refs. [25,26].The calculation of Ref. [19], working in the chiral quark soliton model, of an extremely small width, < 15 MeV stimulated experimental searches with some positive signals, although all of them had very low statistics with at most ∼ 100 counts above a comparable background [13]. Preliminary high statistics photoproduction data of the reaction γp → nK S from the CLAS collaboration [27] sets an upper limit on the yield of the θ + relative to the Λ * (1520) yield at 0.2%. No definitive structure in the nK-invariant mass spectrum is observed at 1540 MeV in this experiment. No experimental information is available on the spin or parity of the state in any experiment done to date.We study the θ + in the non-relativistic flux tube quark model with one-gluon exchange (OGE) and one-pion exchange (OPE) (between the light quarks). We take seriously the possibility that θ + is a narrow reson...

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confidence: 99%

Variational Monte Carlo Study of Pentaquark States

Paris

2005

Phys. Rev. Lett.

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“…This does not consist with a narrow resonance. The mass values in LEPS early experiment [11], DIANA experiments [48,[60][61][62], SAPHIR experiment [51] and JINR experiments [55,56] are around 1540 MeV/c 2 , while the values in HERMES experiment [50], SVD early experiment [49], ITEP's analysis on the old neutrino experiments [52,53] and E522 experiment [57] are near 1530 MeV/c 2 . Besides, the LEPS recent experiment [59], the SVD updated experiment [63] and the ZEUS experiment [54] provide even lower mass values close to 1520 MeV/c 2 , and the OBELIX experiment gives a much higher value.…”

Section: Discussionmentioning

confidence: 99%

“…Since the Θ + has the same quark constituents as the combination of nK + and pK 0 , these two modes are expected as the primary decay channel, and thus are usually used in reconstructions in the experiments. After the first report for the Θ + , the signals were observed by many groups [11,[48][49][50][51][52][53][54][55][56][57][58], and some groups confirmed their results with new data [59][60][61][62][63]. All these results are briefly listed in Table I.…”

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confidence: 91%

Present status on experimental search for pentaquarks

Liu

Mao

2014

Int. J. Mod. Phys. A

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It has been ten years since the first report for a positive strangeness pentaquark-like baryon state. However the existence of the pentaquark state is still controversial. Some contradictions between the experiments are unsolved. In this paper we review the experimental search for the pentaquark candidates $\Theta^+$, $\Theta^{++}$, $\Xi^{--}$, $\Theta_c^0$ and $N^*$ in details. We review the experiments with positive results and compare the experiments with similar conditions but opposite results.Comment: 20 latex pages, 2 figures, to appear in IJMPA as a revie

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“…Following the discovery of Θ + by the LEPS collaboration [1], some experimental collaborations [2,3,4,5,6,7,8,9,10,11,12,13,14] have also confirmed its existence. Its mass is 1539.2 ± 1.6 MeV with a very narrow width of 0.9 ± 0.30 MeV.…”

Section: Introductionmentioning

confidence: 99%

Mixing of pentaquark and molecular states

Liu

et al. 2005

Eur. Phys. J. C

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There are experimental evidences for the existence of narrow states Θ + and Θ c with the same quantum numbers of uudds and uuddc pentaquarks and also N K ( * ) and N D ( * ) molecular states.Their masses deviate from many theoretical estimates of the pure pentaquark and molecular states.In this work we study the possibility that the observed Θ + and Θ c are mixtures of pure pentaquark and molecular states. The mixing parameters are in general related to non-perturbative QCD which are not calculable at present. We determine them by fitting data from known states and then generalize the mechanism to Θ b to predict its mass and width. The mixing mechanism can also naturally explain the narrow width for Θ + and Θ c through destructive interferences, even if the pure pentaquark and molecular states have much larger decay widths. We also briefly discuss the properties of the partner eigenstates of Θ + and Θ c and the possibility of experimentally observe them. Moreover, probable consequences of multi-state mixing are also addressed.

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EVIDENCE OF S = +1 NARROW RESONANCES IN THE SYSTEM $K_s^0 p$

Cited by 15 publications

References 0 publications

Variational Monte Carlo Study of Pentaquark States

Variational Monte Carlo Study of Pentaquark States

Present status on experimental search for pentaquarks

Mixing of pentaquark and molecular states

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