Precision dispersive approaches versus unitarized chiral perturbation theory for the lightest scalar resonances $$\sigma /f_0(500) $$ and $$\kappa /K_0^*(700) $$

Peláez, J. R.; Rodas, A.; Elvira, J. Ruiz de

doi:10.1140/epjs/s11734-021-00142-9

Cited by 21 publications

(21 citation statements)

References 228 publications

(519 reference statements)

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“…The singularities of the scattering amplitude (86) are the same as those of the tetraquark propagator (85). The separate molecular-type singularity, present in T (h) , has been cancelled by a similar singularity resulting from the radiative corrections in T (g ,h) .…”

Section: Bound Statesmentioning

confidence: 97%

“…The previous results mean that the present model does not produce resonances in the vicinity of the two-particle threshold. Resonances can be produced when there are derivative-type couplings [84][85][86], which we have discarded in the present approach. One can also refer to the rectangular well model of [79], where resonances in the S-wave are generally produced far from the real axis.…”

Section: Scattering Length and Effective Rangementioning

confidence: 99%

“…Expanding T [Equation (86)] around E TR , as in (65), one obtains the expression of the tetraquark-two-meson coupling constant squared:…”

Section: Resonancesmentioning

confidence: 99%

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The Interplay between Compact and Molecular Structures in Tetraquarks

Sazdjian

2022

Symmetry

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Due to the cluster reducibility of multiquark operators, a strong interplay exists in tetraquarks between the compact structures, resulting from the direct confining forces acting on quarks and gluons, and the molecular structure, dominated by the mesonic clusters. This issue is studied within an effective field theory approach, where the compact tetraquark is treated as an elementary particle. The key ingredient of the analysis is provided by the primary coupling constant of the compact tetraquark to the two mesonic clusters, considered here in the framework of a scalar interaction. Under the influence of this coupling, an initially formed compact tetraquark bound state evolves towards a new structure, where a molecular configuration is also present. In the strong-coupling limit, the evolution may end with a shallow bound state of the molecular type. The strong-coupling regime is also favored by the large Nc properties of QCD. The interplay between compact and molecular structures may provide a natural explanation of the existence of many shallow bound states.

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Section: Bound Statesmentioning

confidence: 97%

Section: Scattering Length and Effective Rangementioning

confidence: 99%

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The Interplay between Compact and Molecular Structures in Tetraquarks

Sazdjian

2022

Symmetry

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Section: Scattering Length and Effective Rangementioning

confidence: 99%

The interplay between compact and molecular structures in tetraquarks

Sazdjian

2022

Preprint

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Due to the cluster reducibility of multiquark operators, a strong interplay exists in tetraquarks between the compact structure, resulting from the direct confining forces acting on quarks and gluons, and the molecular structure, dominated by the mesonic clusters. This issue is studied within an effective field theory approach, where the compact tetraquark is treated as an elementary particle. The key ingredient of the analysis is provided by the primary coupling constant of the compact tetraquark to the two mesonic clusters. Under the influence of this coupling, an initially formed compact tetraquark bound state evolves towards a new structure, where a molecular configuration is also present. In the strongcoupling limit, the evolution may end with a shallow bound state of the molecular type. The strong-coupling regime is also favored by the large-N c properties of QCD. The interplay between compact and molecular structures may provide a natural explanation of the existence of many shallow bound states.

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“…Peláez et al on Precision dispersive approaches versus unitarized Chiral Perturbation Theory for the lightest scalar resonances σ/f 0 (500) and κ/K * 0 (700) [1] revise the most precise calculations of their pole positions (and that of the f 0 (980) too) that stem from the thorough application of analytical properties of scattering amplitudes satisfying unitarity and crossing symmetry to the present available data on ππ and Kπ scattering, supplemented with Regge theory in the high-energy region. They compare these techniques with some others based on the unitarization of two-body scattering amplitudes calculated in ChPT, which are handicapped by the non-exactly implemented crossing symmetry, lack of multiparticle intermediate states in the s channel and proliferation of ChPT counterterms when higher order ChPT amplitudes are unitarized.…”

Section: Introductionmentioning

confidence: 99%

Topics in light-quark physics

Oller

2021

Eur. Phys. J. Spec. Top.

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This special issue of the European Journal of Physics: Special Topics entitled Topics in Light Quark Physics collects 8 papers with the intention to discuss problems in physical processes involving the particles (mesons and baryons) comprising the lighter part in the spectrum of strong interactions, though some connections to the heavy-quark sector are also discussed. Active and timely problems in this broad field are introduced and covered by experts who root their contributions in the known aspects at the same time that take us to the frontier of knowledge, while introducing in many instances new techniques for present and future further developments. The nature of the lightest scalar resonances, the hunt for the lightest glueballs, the Λ(1405) as a paradigmatic example of two-pole resonances, the pion-nucleon sigma term, two-and three-body scattering amplitudes extracted from lattice QCD, the QCD phase diagram, extrapolations in the number of colors of QCD and their use for addressing properties of its spectrum, and new advances to reach renormalized scattering amplitudes with attractive/repulsive singular potentials are all items covered here.

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Precision dispersive approaches versus unitarized chiral perturbation theory for the lightest scalar resonances $$\sigma /f_0(500) $$ and $$\kappa /K_0^*(700) $$

Cited by 21 publications

References 228 publications

The Interplay between Compact and Molecular Structures in Tetraquarks

The Interplay between Compact and Molecular Structures in Tetraquarks

The interplay between compact and molecular structures in tetraquarks

Topics in light-quark physics

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