η_c→2g强衰变的有限顶角修正及α_s(m_c)的确定

Finite Size Vertex Correction to the Strong Decay of η_c States and a Determination of α_s(m_c)

计算了 ηc 两胶子衰变宽度的有限顶角展开的修正 .通过数值计算 ,得到了 ηc 的零程近似的修正因子为 :γ=1 32 ,利用衰变宽度Γ (ηc 2g) ,抽出强耦合参数αs(mc) =0 2 8± 0 0 5 ,这个值与Γ (J/Ψ 3g)强衰变的顶角修正得到的结果一致 .而Γ (ηc 2g)的有限顶角修正没有Γ (J/Ψ 3g)大 .

We calculate the correction to the two gluon decay width for η\-c due to the finite extension of the vertex function. We get the corrected factor to the zero range vertex γ =1. 32 for η\-c . With the decay width Γ(η\-c2g) we extract the value α\-s (m\-c)=0. 28±0. 05 which agrees with the one calculated from the same correction to process Γ(J/Ψ3g) . This corrction to the process Γ(η\-c2g) is not as large as to the process Γ(J/Ψ3g) .