论文标题
$ p_c $状态的生产$λ_b$衰减
Production of $P_c$ states in $Λ_b$ decays
论文作者
论文摘要
我们开发了一个模型，用于在lambdab -jpsi p k- decays中观察到的PC状态。与其他方法相比，我们获得了与JPSI-P不变质量谱的极好的拟合，在整个不变质量范围内捕获了突出的峰和更广泛的特征。 A distinguishing feature of our model is that whereas Pc(4312), Pc(4380), and Pc(4440) are resonances with Sigmac*-D* constituents, the nature of Pc(4457) is quite different, and can be understood either as a Sigmac-D* threshold cusp, a Lambdac(2595)-D enhancement due to the triangle singularity, or a Lambdac（2595）-D共振。我们提出的实验测量可以区分这些可能性。与其他模型不同，我们的生产机制尊重同源对称性以及弱衰变中颜色增强过程的经验优势，并为数据的整体形状提供了自然的解释。我们的模型与光生生效和lambdab-lambdac-d（*）0 k-衰减的实验约束是一致的，这并不意味着存在在其他模型中无法解释的伴侣状态。
We develop a model for the production of the Pc states observed at LHCb in Lambdab - Jpsi p K- decays. With fewer parameters than other approaches, we obtain excellent fits to the Jpsi-p invariant mass spectrum, capturing both the prominent peaks, and broader features over the full range of invariant mass. A distinguishing feature of our model is that whereas Pc(4312), Pc(4380), and Pc(4440) are resonances with Sigmac*-D* constituents, the nature of Pc(4457) is quite different, and can be understood either as a Sigmac-D* threshold cusp, a Lambdac(2595)-D enhancement due to the triangle singularity, or a Lambdac(2595)-D resonance. We propose experimental measurements that can discriminate among these possibilities. Unlike in other models, our production mechanism respects isospin symmetry and the empirical dominance of colour-enhanced processes in weak decays, and additionally gives a natural explanation for the overall shape of the data. Our model is consistent with experimental constraints from photoproduction and Lambdab - Lambdac-D(*)0 K- decays and it does not imply the existence of partner states whose apparent absence in experiments is unexplained in other models.
