$\frac{ 2\Gamma(\overset{(-)}{B}^0 \to \rho^0 \gamma) - \Gamma(B^{\pm} \to \rho^{\pm} \gamma) }{ 2\Gamma(\overset{(-)}{B}^0 \to \rho^0 \gamma) + \Gamma(B^{\pm} \to \rho^{\pm} \gamma) }$

ExperimentMeasurement [100]$\Delta\chi^2$ReferenceComments
Average$0.11 \pm0.14$Isospin asymmetry with $CP$-average branching fractions.
Belle II$0.109\,^{+0.112}_{-0.117}\,^{+0.078}_{-0.073}$0.00 arXiv:2407.08984Result obtained with a combination of Belle and Belle II datasets. Multiple systematic uncertainties are added in quadrature.
Input values in blue correspond to yet unpublished results.