Preliminary Results on Charmed Meson Spectroscopy

We present preliminary results from the FOCUS experiment (E831 at Fermilab) on the spectroscopy of bound states of a charm quark and a light quark with orbital angular momentum L = 1, called D∗ 2(cū, cd̄). A theoretical framework for the spectrum of heavy-light mesons is given by Heavy Quark Symmetry (HQS), which predicts both narrow and broad states. While the narrow states are well established, the evidence for the broad states (both in the c-quark and in the b-quark sector) is much less stringent . The data for this paper were collected in the Wideband photoproduction experiment FOCUS during the Fermilab 1996–1997 fixed-target run. FOCUS is a considerably upgraded version of a previous experiment, E687 . In FOCUS, a forward multi-particle spectrometer is used to measure the interactions of high-energy photons on a segmented BeO target. We obtained a sample of over 1 million fully reconstructed charm particles in the three major decay modes: D → Kπ,K2π,K3π. The decays D → Kπ, D → Kππ, D → Kπππ, D → Dπ