2004/12/31 by Yongseok Oh, K. Nakayama, T. -S. H. Lee +1 · 3 citations
Physics and Astronomy · #Baryon #Coupling constant #Exotic hadron #Hadron #High-Energy Particle Collisions Research #Invariant (physics) #Meson #Particle physics theoretical and experimental studies #Pentaquark #Quantum Chromodynamics and Particle Interactions #Quark model #hep-ex #hep-ph #nucl-th
paper · pdf · doi:10.1016/j.physrep.2005.10.002
published as Phys.Rept. 423 (2006) 49-89 · 49 pages, 18 figures, REVTeX, to appear in Phys. Rep
arxiv created 2005/10/20 · openalex publication_date 2005/11/29 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The recent developments in the search of exotic pentaquark hadrons are briefly reviewed. We then focus on investigating how the exotic pentaquark Θ(1540) baryon production can be identified in the γN → K K N reactions, focusing on the influence of the background (non-Θ production) mechanisms. By imposing the SU(3) symmetry and using various quark model predictions, we are able to fix the coupling constants for evaluating the kaon backgrounds, the KK production through the intermediate vector meson and tensor meson photoproduction, and the mechanisms involving intermediate Λ(1116), Λ(1405), Λ(1520), Σ(1193), Σ(1385), and Δ(1232) states. The total cross section data of γp → K+K- p is then used to fix the form factors which regularize the background amplitudes so that the signal of Θ(1540) in γn → K+K-n and γp → K0K0p cross sections can be predicted. We find that the predicted K+K- and K+ n invariant mass distributions of the γn → K+ K- n reaction can qualitatively reproduce the shapes of the JLab data. However, the predicted Θ(1540) peak can not be identified unambiguously with the data. High statistics experiments are needed to resolve the problem. We also find that an even-parity Θ is more likely to be detected, while it will be difficult to identify an odd-parity Θ, even if it exists, from the background continuum, if its coupling constants are small as in the present quark model predictions.