Production of excited charm and charm-strange mesons at HERA

Understand

The production of excited charm, D_1(2420)^0 and D_2^*(2460)^0, and charm-strange, D_{s1}(2536)^+-, mesons in ep collisions was measured with the ZEUS detector at HERA using an integrated luminosity of 126 pb^-1.

• Masses, widths and helicity parameters were determined.
• The measured yields were converted to the rates of c quarks hadronising as a given excited charm meson and to the ratios of the dominant D_2^*(2460)^0 and D_{s1}(2536)^+- branching fractions.
• A search for the radially excited charm meson, D^{*'}(2640)^+-, was also performed.