We compare the static nucleon properties in the Chiral Perturbation Theory (χPT) and the Linear Sigma Model (LSM). We consider a chiral model for the nucleon which is based on the linear sigma model with scalar-isosc...We compare the static nucleon properties in the Chiral Perturbation Theory (χPT) and the Linear Sigma Model (LSM). We consider a chiral model for the nucleon which is based on the linear sigma model with scalar-isoscalar and scalarisovector mesons coupled to quarks. We have solved the field equations in the mean field approximation for the hedgehog baryon state with different sets of model parameters. A good investigation of some static nucleon properties is obtained by the LSM.展开更多
Motivated by the successes of relativistic theories in studies of atomic/molecular and nuclear systems and the need for a relativistic chiral force in relativistic nuclear structure studies, we explore a new relativis...Motivated by the successes of relativistic theories in studies of atomic/molecular and nuclear systems and the need for a relativistic chiral force in relativistic nuclear structure studies, we explore a new relativistic scheme to construct the nucleon-nucleon interaction in the framework of covariant chiral effective field theory. The chiral interaction is formulated up to leading order with covariant power counting and a Lorentz invariant chiral Lagrangian.We find that the relativistic scheme induces all six spin operators needed to describe the nuclear force. A detailed investigation of the partial wave potentials shows a better description of the;S——0 and;P;phase shifts than the leading order Weinberg approach, and similar to that of the next-to-leading order Weinberg approach. For the other partial waves with angular momenta J≥1, the relativistic results are almost the same as their leading order non-relativistic counterparts.展开更多
A production representation of partial-wave S matrix is utilized to construct low-energy elastic pion-nucleon scattering amplitudes from cuts and poles on complex Riemann sheets. Among them, the contribution of left-h...A production representation of partial-wave S matrix is utilized to construct low-energy elastic pion-nucleon scattering amplitudes from cuts and poles on complex Riemann sheets. Among them, the contribution of left-hand cuts is estimated using the ■(p^3) results obtained in covariant baryon chiral perturbation theory within the extendedon-nass-shell scheme. By fitting to data on partial-wave phase shifts, it is indicated that the existences of hidden poles in S11 and P11 channels, as conjectured in our previous paper [Eur. Phys. J. C, 78(7): 543(2018)], are firmly established. Specifically, the pole mass of the S11 hidden resonance is determined to be(895±81)-(164±23)i MeV,whereas,the virtual pole in the P11 channel locates at(966±18) MeV. It is found that analyses at the■(p^3) level improves significantly the fit quality, comparing with the previous■(p^2) one. Quantitative studies with cautious physical discussions are also conducted for the other S-and P-wave channels.展开更多
文摘We compare the static nucleon properties in the Chiral Perturbation Theory (χPT) and the Linear Sigma Model (LSM). We consider a chiral model for the nucleon which is based on the linear sigma model with scalar-isoscalar and scalarisovector mesons coupled to quarks. We have solved the field equations in the mean field approximation for the hedgehog baryon state with different sets of model parameters. A good investigation of some static nucleon properties is obtained by the LSM.
基金Supported by National Natural Science Foundation of China(11375024,11522539,11335002,11375120)DFG and NSFC through funds provided to the Sino-German CRC 110“Symmetries and the Emergence of Structure in QCD”(NSFC Grant No.11621131001,DFG Grant No.TRR110)+3 种基金the Major State 973 Program of China(2013CB834400)the China Postdoctoral Science Foundation(2016M600845,2017T100008)the Fundamental Research Funds for the Central Universitiesby the DFG cluster of excellence Origin and Structure of the Universe(www.universe-cluster.de)
文摘Motivated by the successes of relativistic theories in studies of atomic/molecular and nuclear systems and the need for a relativistic chiral force in relativistic nuclear structure studies, we explore a new relativistic scheme to construct the nucleon-nucleon interaction in the framework of covariant chiral effective field theory. The chiral interaction is formulated up to leading order with covariant power counting and a Lorentz invariant chiral Lagrangian.We find that the relativistic scheme induces all six spin operators needed to describe the nuclear force. A detailed investigation of the partial wave potentials shows a better description of the;S——0 and;P;phase shifts than the leading order Weinberg approach, and similar to that of the next-to-leading order Weinberg approach. For the other partial waves with angular momenta J≥1, the relativistic results are almost the same as their leading order non-relativistic counterparts.
基金Supported in part by National Nature Science Foundations of China(NSFC)(10925522,11021092)the Spanish Ministerio de Economía y Competitividad(MINECO)the European Regional Development Fund(ERDF)(FIS2017-84038-C2-1-P,FIS2017-84038-C2-2-P,SEV-2014-0398)
文摘A production representation of partial-wave S matrix is utilized to construct low-energy elastic pion-nucleon scattering amplitudes from cuts and poles on complex Riemann sheets. Among them, the contribution of left-hand cuts is estimated using the ■(p^3) results obtained in covariant baryon chiral perturbation theory within the extendedon-nass-shell scheme. By fitting to data on partial-wave phase shifts, it is indicated that the existences of hidden poles in S11 and P11 channels, as conjectured in our previous paper [Eur. Phys. J. C, 78(7): 543(2018)], are firmly established. Specifically, the pole mass of the S11 hidden resonance is determined to be(895±81)-(164±23)i MeV,whereas,the virtual pole in the P11 channel locates at(966±18) MeV. It is found that analyses at the■(p^3) level improves significantly the fit quality, comparing with the previous■(p^2) one. Quantitative studies with cautious physical discussions are also conducted for the other S-and P-wave channels.
