2015/07/16 by M. Albaladejo, Albaladejo, M., B. Moussallam +1
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #hep-ph
paper · pdf · doi:10.48550/arxiv.1507.04526
33 pages, 14 figures. v2: Some clarifications and corrections of typos
arxiv created 2015/10/22 · arxiv updated 2015/10/23
A model for S-wave ηπ scattering is proposed which could be realistic in an energy range from threshold up to above one GeV, where inelasticity is dominated by the KK channel. The T-matrix, satisfying two-channel unitarity, is given in a form which matches the chiral expansion results at order p4 exactly for the ηπ→ηπ, ηπ→ KK amplitudes and approximately for KK→ KK. It contains six phenomenological parameters. Asymptotic conditions are imposed which ensure a minimal solution of the Muskhelishvili-Omnès problem, thus allowing to compute the ηπ and KK form factor matrix elements of the I=1 scalar current from the T-matrix. The phenomenological parameters are determined such as to reproduce the experimental properties of the a0(980), a0(1450) resonances, as well as the chiral results of the ηπ and KK scalar radii which are predicted to be remarkably small at O(p4). This T-matrix model could be used for a unified treatment of the ηπ final-state interaction problem in processes such as η'→ ηππ, ϕ→ηπγ, or the ηπ initial-state interaction in η→3π.