Off-Shell Extension of the Chiral Reduction Formula

We present a proper off-mass-shell extension of the chiral reduction formula (CHRF) proposed by Yamagishi and Zaned. This is achieved by rewriting the CHRF in a manifestly consistent form with the conventional LSZ reduction formula.Comment: v.2. 16 pages; v.3. 11 pages, Version to apper in Prog. Theor. Phy

Study of nucleon resonances at EBAC@JLab

We present the dynamical origin of the P11 nucleon resonances resulting from a dynamical coupled-channels (DCC) analysis of meson production reactions off a nucleon target, which is conducted at Excited Baryon Analysis Center (EBAC) of Jefferson Lab. Two resonance poles are found in the energy region where the Roper resonance P11(1440) was identified. Furthermore, the two resonance poles and the next higher resonance pole corresponding to P11(1710) are found to originate from a single bare state.Comment: Contribution to 7th Japan-China Joint Nuclear Physics Symposium, Tsukuba, Nov. 9-13, 2009. 5 pages, 2 figure

Extraction of nucleon resonances from global analysis of meson production reactions at EBAC

We report the current status of exploring the dynamical aspect of the excited nucleon states through the comprehensive coupled-channels analysis of meson production reactions at the Excited Baryon Analysis Center of Jefferson Lab.Comment: 4 pages, 3 figures, Contribution to the proceedings of International conference on the structure of baryons (BARYONS'10), Osaka, Japan, Dec. 7-11, 201

An Alternative View of the Dynamical Origin of the P11 Nucleon Resonances: Results from the Excited Baryon Analysis Center

We present an alternative interpretation for the dynamical origin of the P11 nucleon resonances, which results from the dynamical coupled-channels analysis at Excited Baryon Analysis Center of Jefferson Lab. The results indicate the crucial role of the multichannel reaction dynamics in determining the N^* spectrum.Comment: 3 pages, 1 figure. Contribution to the proceedings of the 19th Particles and Nuclei International Conference (PANIC11), Cambridge, MA, USA, July 24-29, 201

Master formula approach to broken chiral U(3)xU(3) symmetry

The master formula approach to chiral symmetry breaking proposed by Yamagishi and Zahed is extended to the U_R(3)xU_L(3) group, in which effects of the U_A(1) anomaly and the flavor symmetry breaking m_u \not= m_d \not= m_s are properly contained. New identities for the gluon topological susceptibility and pi^0, eta, eta' -> gamma^(*) gamma^(*) decays are derived, which exactly embody the consequence from broken chiral symmetry in QCD without relying on any unphysical limit.Comment: Version to appear in PRD, 25 page