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U_A(1) Breaking Effects on the Light Scalar Meson Spectrum

Kenichi Naito·Makoto Oka·Makoto Takizawa·Toru Umekawa
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Abstract

Effects of the U_A(1) breaking interaction on the low-lying nonet scalar mesons are studied using the extended Nambu-Jona-Lasinio model. The strength of the U_A(1) breaking interaction is determined by the electromagnetic decays of the eta meson. We find that the U_A(1) breaking interaction gives rise to about 150 MeV mass difference between the sigma and a_0 mesons. We also find that the strangeness content in the σmeson is about 15%. The calculated mass of the I=1/2 state is about 200 MeV heavier than that of the I=1 state. The order of these masses is not likely to change within this model.

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Kenichi Naito, Makoto Oka, Makoto Takizawa, Toru Umekawa. 2003-05-08. U_A(1) Breaking Effects on the Light Scalar Meson Spectrum. https://doi.org/10.1143/ptp.109.969

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