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تسجيل مستخدم جديدAmplitude Analysis of High Statistics Results on $gammagammatopi^+pi^-$ and the Two Photon Width of Isoscalar States
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We perform an Amplitude Analysis of the world published data on $gammagammatopi^+pi^-$ and $pi^0pi^0$. These are dominated in statistics by the recently published results from Belle on the charged pion channel. Nevertheless, having only limited angular information, a range of solutions remain possible. We present two solutions with $Gamma(f_0(980)togammagamma) = 0.42$ and 0.10 keV, and $Gamma(f_2(1270)togammagamma) = 3.14 pm 0.20$ and $3.82 pm 0.30$ keV, respectively: the former being the solution favoured by $chi^2$, the latter at the edge of acceptability. Models of the structure of the $f_0(980)$ predict two photon widths to be between 0.2 and 0.6 keV, depending on its composition as mainly ${bar K}K$, ${bar s}s$ or ${bar{qq}}qq$. Presently available data cannot yet distinguish unambiguously between these predictions. However, we show how forthcoming results on $gammagamma topi^0pi^0$ can not only discriminate between, but also refine, these classes of partial wave solutions.
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