Physics – Nuclear Physics – Nuclear Theory
Scientific paper
2011-12-09
Physics
Nuclear Physics
Nuclear Theory
23 pages, 14 figures
Scientific paper
We compute nucleon and Roper e.m. elastic and transition form factors using a symmetry-preserving treatment of a contact-interaction. Obtained thereby, the e.m. interactions of baryons are typically described by hard form factors. In contrasting this behaviour with that produced by a momentum-dependent interaction, one achieves comparisons which highlight that elastic scattering and resonance electroproduction experiments probe the infrared evolution of QCD's running masses; e.g., the existence, and location if so, of a zero in the ratio of nucleon Sachs form factors are strongly influenced by the running of the dressed-quark mass. In our description of baryons, diquark correlations are important. These correlations are instrumental in producing a zero in the Dirac form factor of the proton's d-quark; and in determining d_v/u_v(x=1), as we show via a formula that expresses d_v/u_v(x=1) in terms of the nucleon's diquark content. The contact interaction produces a first excitation of the nucleon that is constituted predominantly from axial-vector diquark correlations. This impacts greatly on the gamma*p->P_{11}(1440) form factors. Notably, our quark core contribution to F_2*(Q^2) exhibits a zero at Q^2~0.5mN^2. Faddeev equation treatments of a hadron's quark core usually underestimate its magnetic properties, hence we consider the effect produced by a dressed-quark anomalous e.m. moment. Its inclusion much improves agreement with experiment. On the domain 0
Chang Lei
Cloët Ian C.
Roberts Christopher D.
Wilson Dalziel J.
No associations
LandOfFree
Nucleon and Roper electromagnetic elastic and transition form factors does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Nucleon and Roper electromagnetic elastic and transition form factors, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nucleon and Roper electromagnetic elastic and transition form factors will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-379698