Measurement of the mass and width of the Ds1(2536)+ meson

Abstract

The decay width and mass of the D s 1 ( 2536 ) + meson are measured via the decay channel D + s 1 → D * + K 0 S using 385 fb − 1 of data recorded with the BABAR detector in the vicinity of the Υ ( 4 S ) resonance at the PEP-II asymmetric-energy electron-positron collider. The result for the decay width is Γ ( D + s 1 ) = 0.92 ± 0.03 ( stat . ) ± 0.04 ( syst . ) MeV . For the mass, a value of m ( D + s 1 ) = 2535.08 ± 0.01 ( stat . ) ± 0.15 ( syst . ) MeV / c 2 is obtained. The mass difference between the D + s 1 and the D * + is measured to be m ( D + s 1 ) − m ( D * + ) = 524.83 ± 0.01 ( stat . ) ± 0.04 ( syst . ) MeV / c 2 , representing a significant improvement compared to the current world average. The unnatural spin-parity assignment for the D + s 1 meson is confirmed.