Speaker
Andrii Verbytskyi
Description
The production of the excited charm mesons D_1(2420) and
D*_2(2460) in ep collisions
has been measured with the ZEUS detector at HERA using an integrated luminosity of 373 pb-1.
The masses of the neutral and charged states, the widths of the neutral
states, and the helicity parameter of D_1(2420)^{0} were determined and compared withother measurements and
with theoretical expectations.
The measured helicity parameter of the D_1^0 allows for some
mixing of S- and D-waves in its decay to D*+ pi-. The result is also consistent with a pure D-wave decay.
Ratios of branching fractions of the two decay modes of the D*_2(2460)^0 and D*_2(2460)^+$ states were measured and compared with previous measurements.
The fractions of charm quarks hadronising into D_1 and D*_2 were measured and are consistent with those obtained in
e+e- annihilations.
