PRL導讀-2019年123卷15期

在Λ0 b π + π –系統中觀測到新的共振

We report the observation of a new structure inthe Λb0π+π− spectrum using the full LHCb data set of pp collisions, correspondingto an integrated luminosity of 9 fb−1, collected at s=7, 8, and 13 TeV. A study of the structure suggests its interpretation as a superposition of two almost degenerate narrow states. The masses and widths of these states are measured to be mΛb(6146)0=6146.17±0.33±0.22±0.16MeV, mΛb(6152)0=6152.51±0.26±0.22±0.16MeV, ΓΛb(6146)0=2.9±1.3±0.3 MeV, ΓΛb(6152)0=2.1±0.8±0.3 MeV, with a mass splitting of Δm=6.34±0.32±0.02 MeV, where the first uncertainty is statistical, the second systematic. The third uncertainty for the mass measurements derives from the knowledge of the mass of the Λb0 baryon. The measured masses and widths of these new excited states suggest their possible interpretation as a doublet of Λb(1D)0states.

Observation of New Resonances in the Λ0 bπ + π – System

R. Aaij et al. (LHCb Collaboration)

Phys. Rev. Lett. 123, 152001(2019)

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.152001