New insights on low energy πN scattering amplitudes: comprehensive analyses at 
					
	    
	    
	   level *

Wang, Yu-Fei; Yao, De-Liang; Zheng, Han-Qing

doi:10.1088/1674-1137/43/6/064110

Cited by 20 publications

(61 citation statements)

References 72 publications

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“…More details are referred to Ref. [34]. As side products, for all the S-and P -waves we calculate the R values, representing the interaction range of the πN potential (c.f.…”

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confidence: 99%

On the existence of N*(890) resonance in S11 channel of πN scatterings

2018

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Low-energy partial-wave πN scattering data is reexamined with the help of the production representation of partial-wave S matrix, where branch cuts and poles are thoroughly under consideration. The left-hand cut contribution to the phase shift is determined, with controlled systematic error estimates, by using the results of O(p 3 ) chiral perturbative amplitudes obtained in the extended-on-mass-shell scheme. In S 11 and P 11 channels, severe discrepancies are observed between the phase shift data and the sum of all known contributions. Statistically satisfactory fits to the data can only be achieved by adding extra poles in the two channels. We find that a S 11 resonance pole locates at √ z r = (0.895 ± 0.081) − (0.164 ± 0.023)i GeV, on the complex s-plane. On the other hand, a P 11 virtual pole, as an accompanying partner of the nucleon bound-state pole, locates at √ z v = (0.966 ± 0.018) GeV, slightly above the nucleon pole on the real axis below threshold. Physical origin of the two newly established poles is explored to the best of our knowledge. It is emphasized that the O(p 3 ) calculation greatly improves the fit quality comparing with the previous O(p 2 ) one.The studies in the field of πN scatterings have led to and fertilized many useful ideas and methods in the development of hadron and even particle physics, such as the establishment of dispersion techniques [1], the concepts of finite energy sum rules [2, 3] and duality [4]. In decades, a wealth of experimental data on differential cross section and polarizations [5] has been accumulated. Partial wave analysis of the πN scattering amplitudes has also been performed which results in the discovery of many baryon resonances [6][7][8][9].Efforts in modern studies on πN scatterings focus on a precision description of the πN amplitudes, not only in the physical region but also in the subthreshold region. Baryon chiral perturbation theory (BChPT) [10-12] serves as an appropriate tool for such a purpose, at low energies. The problem of power counting breaking terms [13] in loops, caused by the presence of baryon degrees of freedom in the chiral Lagrangian, is finally overcome by the use of the extended-on-mass-shell subtraction scheme [14]. Though many achievements have been obtained in the perturbation calculations within this scheme [15][16][17][18][19], analyses respecting both exact partial wave unitarity and proper analyticity are still lacking. Hence the use of the dispersion techniques revived in recent years. For example, the analysis based on Roy-Steiner equations [20] has reproduced low-energy phase shift data successfully (see also Refs. [21,22]).More recently, in Ref.[23], low-energy πN scattering has been re-visited with the help of the Peking University (PKU) representation [24-27] -a production parametrization of the unitary partial wave S matrix for two-body elastic scattering amplitudes. The production representation is constructed from first principles. Especially, analyticity and unitarity are automatically built in, hence the fatal defic...

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“…More details are referred to Ref. [34]. As side products, for all the S-and P -waves we calculate the R values, representing the interaction range of the πN potential (c.f.…”

mentioning

confidence: 99%

On the existence of N*(890) resonance in S11 channel of πN scatterings

2018

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“…In the meantime, g 2 πN can be computed by using g 2 πN T l (s p )/S l (s p ), which was already obtained in Ref. [29]. We employed the MAID solution of the fit (The result of DMT is similar), and chose central value √ s = 0.882 − 0.190i for pole position to extract pole residues.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…T (s p ) can be obtained through S(s p ) = 1 + 2iρ πN (s p )T (s p ) = 0 and 1 S (sp) is just the residue of S II as explained Ref. [29].…”

Section: Numerical Resultsmentioning

confidence: 99%

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Dispersive analysis of low energy $γ^* N\rightarrowπN$ process

Cao,

Ma,

Zheng

2021

Preprint

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We use a dispersion representation based on unitarity and analyticity to study the low energy γ * N → πN process in the S11 channel. Final state interactions among the πN system are critical to this analysis. The left-hand part of the partial wave amplitude is imported from O(p 2 ) chiral perturbation theory result. On the right hand part, the final state interaction is calculated through Omnès formula in S-wave. It is found that good numerical fit can be achieved with only one subtraction parameter, and the eletroproduction experimental data of multipole amplitudes E0+, S0+ in the energy region below ∆(1232) are well described when the photon virtuality Q 2 ≤ 0.1GeV 2 . The γ * N coupling of the possible sub-threshold resonance in S11 channel is also investigated.

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“…Here, we also ignore the contribution of the sub-threshold resonance (pole) N * (890)[36,37]. Because the amplitudes in the physical region can be estimated by chiral low-order results.…”

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confidence: 99%

Radiative Correction to Lepton Proton Scatterings in Manifestly Lorentz-Invariant Chiral Perturbation Theory

Cao,

Li,

Zheng

2021

Preprint

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Manifestly lorentz-invariant baryon chiral perturbation theory is used to calculate the radiative correction of low energy elastic lepton proton scatterings. Corrections of differential cross section and charge asymmetry are given at next-to-leading order with nonzero lepton mass, in which both are infrared and ultraviolet finite. The results are basically consistent with previous predictions based on hadron model, but somewhat different from calculations based on heavy baryon chiral perturbation theory, especially in charge asymmetry.

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New insights on low energy πN scattering amplitudes: comprehensive analyses at level *

Cited by 20 publications

References 72 publications

On the existence of N*(890) resonance in S11 channel of πN scatterings

On the existence of N*(890) resonance in S11 channel of πN scatterings

Dispersive analysis of low energy $γ^* N\rightarrowπN$ process

Radiative Correction to Lepton Proton Scatterings in Manifestly Lorentz-Invariant Chiral Perturbation Theory

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