2008/02/29 by C. S. An, Chun-Sheng An, B. S. Zou · 3 citations
Physics and Astronomy · #Amplitude #Bar (unit) #Helicity #High-Energy Particle Collisions Research #Momentum (technical analysis) #Nuclear physics #Nucleon #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Quark #Quark model #Quarkonium #Resonance (particle physics) #nucl-th
paper · pdf · doi:10.1140/epja/i2008-10698-x
version to appear in Eur. Phys. J. A
arxiv created 2009/01/19 · openalex publication_date 2009/01/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The helicity amplitudes Ap1/2 and Sp1/2 for the electromagnetic transition γ* N→ N*(1535) are calculated in the quark model that is extended to include the lowest lying qqqqq components in addition to the qqq component. It is found that with admixture of 5-quark components with a proportion of 20% in the nucleon and 25-65% in the N*(1535) resonance the calculated helicity amplitude Ap1/2 decreases at the photon point, Q2=0 to the empirical range. The qqqqq components contain s s pairs, which is consistent with the substantial width for Nη decay of the N*(1535). The best description of the momentum dependence of the empirical helicity amplitudes is obtained by assuming that the qqqqq components are more compact than the qqq component. However, this version of extended quark model still does not lead to a satisfactory simultaneous description of both Ap1/2 and Sp1/2 although with significant improvement.