On baryon resonances and chiral symmetry

Kolomeitsev, E. É.; Lutz, Matthias

doi:10.1016/j.physletb.2004.01.066

Cited by 239 publications

(350 citation statements)

References 26 publications

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“…The importance of pion (cloud) contributions to the transition form factors has also been confirmed by the lattice calculations [29]. Alternative descriptions include the representation of N (1440)P 11 as a gluonic baryon excitation [30,31] and the possibility that nucleon resonances are meson-baryon molecules generated in chiral coupled-channel dynamics [32][33][34][35][36]. Relations between baryon electromagnetic form factors and generalized parton distributions (GPDs) have also been formulated that connect these two different notions to describe the baryon structure [37,38].…”

Section: Introductionmentioning

confidence: 77%

“…Combined with the difficulties of quark models to describe the substantial coupling of N (1535)S 11 to the ηN channel [20] and to strange particles [21,22], the difficulty in the description of the sign of S 1/2 can be indicative of a large meson-cloud contribution and/or of additional qq components in this state [24]. Alternative representations of the N (1535)S 11 as a meson-baryon molecule have been also discussed [32,[34][35][36].…”

Section: N(1535)s 11 Resonancementioning

confidence: 99%

See 1 more Smart Citation

Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction

Aznauryan¹,

Burkert²,

Biselli³

et al. 2009

Phys. Rev. C

250

380

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We present results on the electroexcitation of the low mass resonances (1232)P 33 , N (1440)P 11 , N (1520)D 13 , and N (1535)S 11 in a wide range of Q 2 . The results were obtained in the comprehensive analysis of data from the Continuous Electron Beam Accelerator Facility (CEBAF) large acceptance spectrometer (CLAS) detector at the Thomas Jefferson National Accelerator Facility (JLab) on differential cross sections, longitudinally polarized beam asymmetries, and longitudinal target and beam-target asymmetries for π electroproduction off the proton. The data were analyzed using two conceptually different approaches-fixed-t dispersion relations and a unitary isobar model-allowing us to draw conclusions on the model sensitivity of the obtained electrocoupling amplitudes. The amplitudes for the (1232)P 33 show the importance of a meson-cloud contribution to quantitatively explain the magnetic dipole strength, as well as the electric and scalar quadrupole transitions. They do not show any tendency of approaching the pQCD regime for Q 2 6 GeV 2 . For the Roper resonance, N (1440)P 11 , the data provide strong evidence that this state is a predominantly radial excitation of a three-quark (3q) ground state. Measured in pion electroproduction, the transverse helicity amplitude for the N (1535)S 11 allowed us to obtain the branching ratios of this state to the πN and ηN channels via comparison with the results extracted from η electroproduction. The extensive CLAS data also enabled the extraction of the γ * p → N (1520)D 13 and N (1535)S 11 longitudinal helicity amplitudes with good precision. For the N (1535)S 11 , these results became a challenge for quark models and may be indicative of large meson-cloud contributions or of representations of this state that differ from a 3q excitation. The transverse amplitudes for the N (1520)D 13 clearly show the rapid changeover from helicity-3/2 dominance at the real photon point to helicity-1/2 dominance at Q 2 > 1 GeV 2 , confirming a long-standing prediction of the constituent quark model.

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Section: Introductionmentioning

confidence: 77%

Section: N(1535)s 11 Resonancementioning

confidence: 99%

Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction

Aznauryan¹,

Burkert²,

Biselli³

et al. 2009

Phys. Rev. C

250

380

View full text Add to dashboard Cite

show abstract

“…This state has also been investigated by Kolomeitsev and Luta in the χ-BS(3) approach [10]. In the present work we analyze the property of the one-gluon-exchange (OGE) interaction in ∆K states with L = 0 and our results show that the OGE interaction is attractive for I = 1 while repulsive for I = 2.…”

Section: Introductionmentioning

confidence: 77%

NKandΔKstates in the chiralSU(

2004

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The isospin I = 0 and I = 1 kaon-nucleon S, P , D, F wave phase shifts are studied in the chiral SU(3) quark model by solving the resonating group method (RGM) equation. The calculated phase shifts for different partial waves are in agreement with the experimental data. Furthermore, the structures of the ∆K states with L = 0, I = 1 and I = 2 are investigated. We find that the interaction between ∆ and K in the case of L = 0, I = 1 is attractive, which is not like the situation of the N K system, where the S-wave interactions between N and K for both I = 0 and I = 1 are repulsive. Our numerical results also show that when the model parameters are taken to be the same as in our previous N N and Y N scattering calculations, the ∆K state with L = 0 and I = 1 is a weakly bound state with about 2 MeV binding energy, while the one with I = 2 is unbound in the present one-channel calculation.

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“…For the physics of resonances the connection is even more loose. There are recent approaches which explain some hadronic resonances as dynamically generated from chiral dynamics [15][16][17][18][19][20][21], but again this primarily points towards an intimate connection between hadron physics and chiral symmetry breaking and not so much chiral restoration. As suggested, e.g., in [2,22] the link to chiral restoration might be indirect: The in-medium broadening could be understood as a step towards deconfinement.…”

Section: Introductionmentioning

confidence: 99%

The impact of chirally odd condensates on the rho meson

et al. 2012

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Based on QCD sum rules we explore the consequences of a pure chiral restoration scenario for the ρ meson, where all chiral symmetry breaking condensates are dropped whereas the chirally symmetric condensates remain at their vacuum values. This pure chiral restoration scenario causes the drop of the ρ spectral moment by about 120 MeV. The complementarity of mass shift and broadening is discussed. A simple parametrization of the ρ spectral function leads to a width of about 600 MeV if no shift of the peak position is assumed.

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On baryon resonances and chiral symmetry

Abstract: We study J P = (

Cited by 239 publications

References 26 publications

Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction

Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction

NKandΔKstates in the chiralSU(

The impact of chirally odd condensates on the rho meson

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