Comment on “ Study of D sJ decays to D ∗ K in inclusive e + e − interactions ”

We comment on the recent observation of the decay mode D sJ (2860) → DK by the BABAR Collaboration [B. Aubert et al. (BABAR Collaboration), arXiv:0908.0806], and contest their peremptory conclusion that the data exclude a 0 assignment for the D sJ (2860). In particular, we argue that the observed branching fraction B(D sJ (2860) → DK)/B(D sJ (2860) → DK) = 1.1 ± 0.15 ± 0.19 supports the existence of two largely overlapping resonances at about 2.86 GeV, namely a pair of radially excited tensor (2) and scalar (0) cs̄ states. This scenario is further justified by comparing with the corresponding excited charmonium states. Also other aspects of the charm-strange spectrum are discussed. In a very recent study of decays of charm-strange mesons [1], the BABAR Collaboration for the first time observed the decay D sJ (2860) → DK. When the D sJ (2860) meson was discovered by BABAR [2], only the DK decay mode was detected, which made an assignment as a radially excited scalar cs̄ meson plausible [3–5], though other configurations such as a 3 state [5–7] could not be excluded. For a discussion of additional options, see Ref. [8]. The now observed DK mode seems to exlude the 0 scenario for the D sJ (2860), as concluded by BABAR. However, in the following we shall show that the true situation may be subtler, involving two overlapping resonances, one scalar (J = 0) and one tensor (J = 2) charm-strange meson. The BABAR angular analysis of the D sJ (2860) → DK decays supports natural parity for the resonance, i.e., J = 0, 1, 2, 3, . . .. Ruling out for the moment the scalar hypothesis, experiment also seems to eliminate the solution of Refs. [6, 7], viz. 3 (1 3D3). Namely, the