Measurements of the branching fractions and and tests of QCD factorization

Krohn, J.-F.*; Tanida, Kiyoshi   ; Belle Collaboration*; 198 of others*

Using meson pairs recorded by the Belle experiment at the KEKB collider, we report the branching fractions and ; the quoted uncertainties are statistical and systematic, respectively. A measurement of the ratio of these branching fractions is also presented, , where systematic uncertainties due to the meson reconstruction cancel out. Furthermore, we report a new QCD factorization test based on the measured ratios for and decays at squared momentum transfer values equivalent to the mass of the or hadron. The parameters are measured to be and , where the last uncertainties account for all external inputs. These values are approximately lower than those expected from theoretical predictions. Subsequently, flavor symmetry is tested by measuring the ratios for pions and kaons, , as well as for different particle species. The ratio is consistent with unity and therefore no evidence for symmetry breaking effects is found at the precision level.