Observation of a narrow resonance of mass 2.46 GeV/c² decaying to D_s^*+ π⁰ and confirmation of the D*_sJ (2317) state

Authors

• Dave Z. Besson, University of Kansas - LawrenceFollow
• Kenneth A. Bloom, University of Nebraska-LincolnFollow
• Cornell Electronic Storage Ring

Document Type

Article

Date of this Version

8-28-2003

Comments

Published by American Physical Society. Phys. Rev. D 68, 012003 (2003). http://prd.aps.org. Copyright © 2003 American Physical Society. Permission to use.

Abstract

Using 13.5 fb^-1 of e⁺e^- annihilation data collected with the CLEO II detector, we have observed a narrow resonance decaying to D_s^*+π⁰ with a mass near 2.46 GeV/c². The search for such a state was motivated by the recent discovery by the BaBar Collaboration of a narrow state at 2.32 GeV/c², the D_sJ^*(2317) ⁺, that decays to D_s⁺ π⁰. Reconstructing the D_s⁺ π⁰ and D_s^*+ π⁰ final states in CLEO data, we observe peaks in both of the corresponding reconstructed mass difference distributions, ΔM(D_s π⁰) = M (D_s π⁰)–M (D_s) and ΔM(D_s^* π⁰) = M (D_s^* π⁰)–M (D_s^*), both of them at values near 350 MeV/c². We interpret these peaks as signatures of two distinct states, the D_sJ^* (2317)⁺ plus a new state, designated as the D_sJ(2463) ⁺. Because of the similar ΔM values, each of these states represents a source of background for the other if photons are lost, ignored or added. A quantitative accounting of these reflections confirms that both states exist. We have measured the mean mass differences < ΔM (D_sπ⁰)> = 350.0±1.2 (stat)±1.0 (syst) MeV/c² for the D_sJ^* (2317)⁺ state, and < ΔMD_s^* π⁰)> = 351.2±1.7 (stat)±1.0 (syst) MeV/c² for the new D_sJ(2463)⁺ state. We have also searched, but find no evidence, for decays of the two states via the channels D_s^*+ γ, D_s⁺ γ, and D_s⁺ π sup>+ π sup>-. The observations of the two states at 2.32 and 2.46 GeV/c², in the D_s⁺ π⁰ and D_s^*+ π⁰ decay channels, respectively, are consistent with their interpretations as cs-bar mesons with an orbital angular momentum L = 1 and spin and parity J^P = 0⁺ and 1⁺.