arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0712.0885hep-phhep-exnucl-th
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Belle实验后$γγ\toππ$中最轻的标量和张量共振

Lightest scalar and tensor resonances in $γγ\toππ$ after the Belle experiment

N. N. Achasov, G. N. Shestakov

摘要:

新的高统计Belle数据的$γγ\toπ^+π^-$反应截面测量范围内的π介子对不变质量$\sqrt{s}$之间的0.8 GeV和1.5 GeV进行了分析,以澄清周围的$σ(600)$,$f_0(980)$,和$f_2(1270)$共振$γγ$碰撞的现状。结果表明,$σ(600)$和$f_0(980)$共振与$γγ$的直接耦合常数很小,$σ(600)\toγγ$和$f_0(980)\toγγ$衰变分别是由$π^+π^-$和$K^+K^-$环机制引起的四夸克跃迁. $σ(600)$共振的手性屏蔽发生在反应$γγ\toππ$以及$ππ$散射中。同时描述的$γγ\toπ^+π^-$和$γγ\toπ^0π^0$ Belle数据的一些结果。特别地,获得了以下$f_2(1270)\toγγ$衰变宽度的初步估计:$Γ_{f_2\toγγ}(m^2_{f_2})\approx 3.68$ keV。

英文摘要:

New high statistics Belle data on the $γγ\toπ^+π^-$ reaction cross section measured in the range of pion-pair invariant masses $\sqrt{s}$ between 0.8 GeV and 1.5 GeV are analyzed to clarify the current situation around the $σ(600)$, $f_0(980)$, and $f_2(1270)$ resonances in $γγ$ collisions. The present analysis shows that the direct coupling constants of the $σ(600)$ and $f_0(980)$ resonances to $γγ$ are small, and the $σ(600)\toγγ$ and $f_0(980)\toγγ$ decays are four-quark transitions caused by the $π^+π^-$ and $K^+K^-$ loop mechanisms, respectively. The chiral shielding of the $σ(600)$ resonance takes place in the reactions $γγ\toππ$ as well as in $ππ$ scattering. Some results of a simultaneous description of the $γγ\toπ^+π^-$ and $γγ\toπ^0π^0$ Belle data are also presented. In particular, the following tentative estimate of the $f_2(1270)\toγγ$ decay width is obtained: $Γ_{f_2\toγγ}(m^2_{f_2})\approx 3.68$ 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。

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