Eur. Phys. J. A (2007) 34: 293-301
https://doi.org/10.1140/epja/i2007-10506-3

Regular Article - Theoretical Physics

Properties of the πη,,σ, f₀(980) and a₀(980) mesons and their relevance for the polarizabilities of the nucleon

Zweites Physikalisches Institut der Universität Göttingen, Friedrich-Hund-Platz 1, D-37077, Göttingen, Germany

^* e-mail: mschuma3@gwdg.de

Received: 10 August 2007
Accepted: 4 December 2007
Published online: 18 December 2007

Abstract

The signs and values of the two-photon couplings F _Mγγ of mesons (M) and their couplings g_MNN to the nucleon as entering into the t -channel parts of the difference of the electromagnetic polarizabilities (α - β) and the backward angle spin polarizabilities γ_π are determined. The excellent agreement achieved with the experimental polarizabilities of the proton makes it possible to make reliable predictions for the neutron. The results obtained are α_n = 13.4±1.0 , β_n = 1.8±1.0 (10^-4fm^3), and γ⁽ⁿ⁾ _π = 57.6±1.8 (10^-4fm^4). New empirical information on the flavor wave functions of the f ₀(980) - and the a ₀(980) -meson is obtained.