f_0(400—1200)物理本质的探讨

On the Nature of f_0(400-1200)

对f0 ( 40 0— 1 2 0 0 )的物理本质进行了探讨 ,将其分解为三部分 :t道 ρ介子和f2 ( 1 2 70 )介子交换部分以及一个很宽的s道共振态f0 (X) .在ππ不变质量1 .2GeV以下 ,用t道ρ介子交换就可以很好地解释同位旋为 2的ππS波散射实验数据 .但是 ,在能量高于 1 .2GeV时 ,t道f2 ( 1 2 70 )介子交换的贡献必须计入 .利用同位旋为 2的ππS波散射过程对t道ρ介子和f2 ( 1 2 70 )介子交换中的形状因子进行约束 ,通过重新拟合CERN M櫣ｎｉｃｈ(CM)实验数据来获得f0 (X)的参数 .结果表明 ,确实需要引入一个在 1 .6— 1 .7GeV附近具有极点的较宽的 0 ++的共振态 ,其极点是 ( 1 .69-0 .2 6i)GeV .

We discuss about the nature of f 0(400-1200) which we decompose into three parts, i.e., t-channel ρ meson and f 2(1270) meson exchange plus an additional s-channel resonance f 0(X). Below 1.2GeV of ππ invariant mass, t-channel ρ meson exchange can explain the I=2 ππ S-wave scattering very well. However, the f 2(1270) meson exchange must be considered for the ππ invariant mass above 1.2GeV. With the t-channel ρ meson and f 2(1270) meson exchange fixed by the isotensor ππ→ππ S-wave scattering, we re-fit the CERN-Mülich(CM) data on ππ scattering to get parameters for the f 0(X). We find that it is necessary to introduce a broad 0 ++ resonance with a pole about 1.6-1.7GeV.