Table 3.

Slope parameter and chiral anomaly from the sum rules (38) and (39). For each fit and data set the upper line refers to the slope in units of ${10}^{-3}$, while the lower line gives the sum-rule value for $F_{\mathit{\pi }\mathit{\gamma }\mathit{\gamma }}$ normalized to (3). The ranges correspond to the uncertainty due to the $\mathit{\pi }\mathit{\pi }$ phase shift and ${\mathit{\Lambda }}_{3\mathit{\pi }}$

	SND+BaBar	HLMNT
Fit below $1.1\text{GeV}$	$30.4\dots 31.2$	$30.1\dots 30.9$
${\mathit{\Lambda }}_{{\mathit{\pi }}^0}=1.1\text{GeV}$	$0.989\dots 1.021$	$0.976\dots 1.008$
Fit below $1.8\text{GeV}$	$30.6\dots 31.4$	$30.4\dots 31.2$
${\mathit{\Lambda }}_{{\mathit{\pi }}^0}=1.1\text{GeV}$	$0.992\dots 1.026$	$0.985\dots 1.019$
Fit below $1.8\text{GeV}$	$30.4\dots 31.2$	$30.3\dots 31.1$
${\mathit{\Lambda }}_{{\mathit{\pi }}^0}=1.4\text{GeV}$	$0.959\dots 0.987$	$0.962\dots 0.990$
Fit below $1.8\text{GeV}$	$30.3\dots 31.1$	$30.2\dots 31.0$
${\mathit{\Lambda }}_{{\mathit{\pi }}^0}=1.8\text{GeV}$	$0.944\dots 0.966$	$0.947\dots 0.970$