<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>Λ</mml:mi><mml:mo>(</mml:mo><mml:mn>1405</mml:mn><mml:mo>)</mml:mo></mml:mrow></mml:math>production in the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mi>π</mml:mi><mml:mo>−</mml:mo></mml:msup><mml:mi>p</mml:mi><mml:mo>→</mml:mo><mml:msup><mml:mi>K</mml:mi><mml:mn>0</mml:mn></mml:msup><mml:mi>π</mml:mi><mml:mi>Σ</mml:mi></mml:mrow></mml:math>reaction

Hyodo, Tetsuo; Oset, E.; Ramos, À.; Vacas, M. J. Vicente

doi:10.1103/physrevc.68.065203

Cited by 111 publications

(160 citation statements)

References 28 publications

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“…Different experiments which favor mechanisms that give a bigger weight to one of these channels would lead to very different widths of the resonance. This is the case with the recent findings that the Λ(1405) resonance corresponds to actually two poles and different experiments favor one or the other pole, leading to different visible widths of the resonance [17,18,29].…”

Section: S = 1 I = 1/2mentioning

confidence: 71%

Low lying axial-vector mesons as dynamically generated resonances

2005

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We make a theoretical study of the s-wave interaction of the nonet of vector mesons with the octet of pseudoscalar mesons starting from a chiral invariant Lagrangian and implementing unitarity in coupled channels. By looking for poles in the unphysical Riemann sheets of the unitarized scattering amplitudes, we get two octets and one singlet of axial-vector dynamically generated resonances. The poles found can be associated to most of the low lying axial-vector resonances quoted in the Particle Data Book: b 1 (1235), h 1 (1170), h 1 (1380), a 1 (1260), f 1 (1285) and two poles to the K 1 (1270) resonance. We evaluate the couplings of the resonances to the V P states and the partial decay widths in order to reinforce the arguments in the discussion.

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Section: S = 1 I = 1/2mentioning

confidence: 71%

Low lying axial-vector mesons as dynamically generated resonances

2005

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“…This finding unveils the structure of the Λ(1405) as a superposition of two states [6,8], which have been studied both theoretically and experimentally [9]. The structure of the Λ(1405) has a large impact for the study of thē KN interaction [10], which is eventually important for the study of the kaonic nuclei and kaon condensation in the neutron star [11].…”

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confidence: 99%

Structure of theΛ(1405)baryon resonance from its largeNcbehavior

Hyodo

Jido²,

Roca

2008

Phys. Rev. D

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We study the behavior with the number of colors (Nc) of the two poles associated to the Λ(1405) resonance obtained dynamically within the chiral unitary approach. The leading order chiral mesonbaryon interaction manifests a nontrivial Nc dependence for SU(3) baryons, which gives a finite attractive interaction in some channels in the large Nc limit. As a consequence, the SU(3) singlet (KN ) component of the Λ(1405) survives in the large Nc limit as a bound state, while the other components dissolve into the continuum. The Nc dependence of the decay widths shows different behavior from the general counting rule for a qqq state, indicating the dynamical origin of the two poles for the Λ(1405) resonance. PACS numbers: 11.15.Pg, 14.20.Jn, 11.30.Rd The quest for the understanding of the nature of the hadronic spectrum is one of the most challenging issues in particle physics. Especially the structure of hadronic resonances is one of the cornerstones in this field. Recently it has been suggested that multiquark and/or hadronic components of some resonances in intermediate energies prevail over the simple mesonic qq and baryonic qqq components. For instance, the light scalar mesons have been investigated in the four-quark picture [1], in the mesonic molecular picture [2], and in lattice QCD [3]. Methods to clarify the internal structure of the hadrons are called for. This is one of the main aims of the present work, in the baryonic sector.Despite the success of QCD as the theory for the strong interactions, the inherent confinement properties of quarks and gluons make its direct applicability to investigate the hadron structure far from being feasible. One of the most powerful tools to investigate the properties of hadrons are the effective theories of QCD, such as chiral perturbation theory (ChPT) [4] and its recent development, chiral unitary approach [2,5,6,7]. ChPT provides hadronic interactions based on a systematic lowenergy expansion. The nonperturbative resummation of the low-energy interactions required by the unitarity condition leads to the success of the chiral unitary approaches in a variety of hadron scatterings with many hadronic resonances being dynamically generated.It is particularly interesting that the Λ(1405) is well reproduced in the chiral unitary approach as a dynamically generated resonance in the s-wave meson-baryon scattering with strangeness S = −1 and isospin I = 0 [5,6,7]. This finding unveils the structure of the Λ(1405) as a superposition of two states [6,8], which have been studied both theoretically and experimentally [9]. The structure of the Λ(1405) has a large impact for the study of thē KN interaction [10], which is eventually important for the study of the kaonic nuclei and kaon condensation in the neutron star [11]. The works based on the chiral unitary approach have shed new light on the understanding of the nature of the Λ(1405) resonance, reinforcing the dynamical or "molecular" origin versus the qqq picture.The expansion in the inverse of the number of colors, 1/N c , is a...

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“…The study of the present reaction, complemental to the one of Ref. [12] for the π − p → K 0 πΣ reaction, has shown that the quite different shapes of the Λ(1405) resonance seen in these experiments can be interpreted in favour of the existence of two poles with the corresponding states having the characteristics predicted by the chiral theoretical calculations. Besides demonstrating once more the great predictive power of the chiral unitary theories, this combined study of the two reactions gives the first clear evidence of the two-pole nature of the Λ(1405).…”

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Evidence for two Λ(1405) resonance states

Oset¹,

Magas²,

Ramos³

2006

AIP Conference Proceedings

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The K − p → π 0 π 0 Σ 0 reaction is studied within a chiral unitary model. The distribution of π 0 Σ 0 states forming the Λ(1405) shows, in agreement with a recent experiment, a peak at 1420 MeV and a relatively narrow width of Γ = 38 MeV. We use these data in combination with those of the π − p → K 0 πΣ reaction and elements of chiral unitary theory to prove that there are two Λ(1405) states instead of one as so far assumed.The history of the Λ(1405) as a dynamical resonance generated from the interaction of meson baryon components in coupled channels has experienced a boost within the context of unitary extensions of chiral perturbation theory (U χP T ) [1,2,3,4,5], where the lowest order chiral Lagrangian and unitarity in coupled channels generates the Λ(1405) and leads to good agreement with the K − p reactions. The surprise, however, came with the realization that there are two poles in the neighborhood of the Λ(1405) both contributing to the final experimental invariant mass distribution [3,4,5,6,7,8,9]. The properties of these two states are quite different, one has a mass around 1390 MeV, a large width of about 130 MeV

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Λ(1405)production in theπ−p→K0πΣreaction

Cited by 111 publications

References 28 publications

Low lying axial-vector mesons as dynamically generated resonances

Low lying axial-vector mesons as dynamically generated resonances

Structure of theΛ(1405)baryon resonance from its largeNcbehavior

Evidence for two Λ(1405) resonance states

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