Study of $D^{**}$ and $D^{*'}$ Production in B and C Jets, with the DELPHI Detector

Using D$^{*+}$ mesons exclusively reconstructed in the DELPHI detector at LEP, orbital and radial excitations of non strange charmed mesons are studied. The multiplicities of the two narrow $D^0_1$ and $D^{*0}_2$ orbital excitations are measured in $Z^0 \to c \bar c$ and $Z^0 \to b \bar b$ decays. Preliminary results are obtained on the production of broad D$^{**}$ states, using B meson semi-leptonic decays. A narrow signal of 66 $\pm$ 14 events is observed in the $(D^{*+} \pi^+ \pi^-)$ final state, interpreted as the first evidence of the predicted $D^{*'}$ radial excitation.