Angular analysis of the e+e- → D(*)D* process near the open-charm threshold using initial-state radiation

We report new measurement of the exclusive e + e - → D (*)± D *∓ cross sections as a function of center-of-mass energy from the D (∗)± D ∗∓ threshold up to = 6.0 GeV with initial state radiation. The analysis is based on a data sample collected by the Belle detector with an integrated luminosity of 951 fb−1 . The accuracy of the cross section measurement is increased by a factor of 2 in comparison with the first Belle study. We have performed the first angular analysis of the e + e - → D ∗± D ∗∓ process and decomposed this exclusive cross section into three components corresponding to the different D ∗ helicities.