arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0810.2201hep-phhep-exnucl-th
收藏

锂离子标量共振与γγ \to ππ反应动力学

Lightest Scalar Resonances and the Dynamics of the γγ\toππReactions

N. N. Achasov, G. N. Shestakov

摘要:

对γγ \to π^+π^-和γγ \to π^0π^0反应的高统计Belle数据进行了联合分析。这些反应的能量低于1.5 GeV的主要动力学机制已被揭示。结果表明,σ(600)和f_0(980)共振态与γ γ对的直接耦合常数很小,σ(600)\to γγ和f_0(980)\to γγ衰变是四夸克跃迁,主要分别由π^+π^-和K^+K^-圈机制引起。强调了σ(600)共振的手征屏蔽的作用。在共振质量分布上平均的f_0(980)\to γγ和σ(600)\to γγ衰变的宽度,以及f_2(1270)\to γγ衰变的宽度,估计为(Γ_{f_0 \to γγ})_{ππ} \approx 0.19 keV,(Γ_{σ \to γγ})_{ππ} \approx 0.45 keV,和Γ_{f_2 \to γγ}(m^2_{f_2})\approx 3.8$ keV。

英文摘要:

The high-statistics Belle data on the γγ\toπ^+π^- and γγ\toπ^0π^0 reactions have been jointly analyzed. The main dynamical mechanisms of these reactions for energies below 1.5 GeV have been revealed. It has been shown that the direct coupling constants of the σ(600) and f_0(980) resonances with a γγpair are small and that the σ(600)\toγγand f_0(980)\toγγdecays are four-quark transitions due primarily to π^+π^- and K^+K^- loop mechanisms, respectively. The role of the chiral shielding of the σ(600) resonance is emphasized. The widths of the f_0(980)\toγγand σ(600)\toγγdecays averaged over the resonance mass distributions, as well as the width of the f_2(1270)\toγγdecay, are estimated as (Γ_{f_0\toγγ})_{ππ}\approx 0.19 keV, (Γ_{σ\toγγ})_{ππ}\approx 0.45 keV, and Γ_{f_2\toγγ}(m^2_{f_2})\approx 3.8$ keV.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑