Do large QCD corrections to di-Higgs decay survive parton showering? A study of $HH\to b\overline{b }\gamma \gamma $

While significant effort has been devoted to precision calculations of the production of two Higgs bosons via gluon fusion, the treatment of their decays in this process has only recently begun to attract attention. It has been found that fixed-order QCD corrections to fiducial di-Higgs decay rates involving the b (b) over bar decay channel can be substantial. Considering HH -> b (b) over bar gamma gamma, we show that such corrections arise predominantly from sensitivity to soft and collinear QCD radiation at fixed order, and that they are largely washed out once parton showers are included.