标题： B- 介子衰变为 Lambda_c+ pbar pi- 的衰变机制研究以及对 (Lambda_c+ pbar) 系统中低质量结构的观察 显示英文标题

标题： Study of decay mechanisms in B- -> Lambda_c+ pbar pi- decay and observation of low mass structure in the (Lambda_c+ pbar) system

摘要： 使用在KEKB e+e-对撞机上由Belle探测器收集的1.52亿个BBbar对，我们对三体含 charm 介子衰变 B- -> Lambda_c+ p_bar pi- 进行了Dalitz图分析。 首次观察到中间两体衰变 B- -> Sigma_c(2455)0 p_bar，其分支比为 (3.67^{+0.74}_{-0.66}+-0.36+-0.95)x10^(-5)，统计显著性为8.4sigma。 我们还在 (Lambda_c+ p_bar) 系统中观察到一个低质量增强，可以参数化为一个Breit-Wigner函数，质量为 (3.35^{+0.01}_{-0.02}+-0.02)GeV/c^2，宽度为 (0.07^{+0.04}_{-0.03}+-0.04)GeV/c^2。 我们测量对应的衰变分支比的乘积为(3.87^{+0.77}_{-0.72}+-0.43+-1.01)x10^(-5) ，具有6.2sigma的统计显著性。 误差包括统计误差、系统误差以及Lambda_c^+ -> pK-pi+衰变分支比的误差。 显示英文摘要

摘要： Using a sample of 152 million BBbar pairs accumulated with the Belle detector at the KEKB e+e- collider, we perform a Dalitz plot analysis of the three-body charmed decay B- -> Lambda_c+ p_bar pi-. The intermediate two-body decay B- -> Sigma_c(2455)0 p_bar is observed for the first time with a branching fraction of (3.67^{+0.74}_{-0.66}+-0.36+-0.95)x10^(-5) and a statistical significance of 8.4sigma. We also observe a low-mass enhancement in the (Lambda_c+ p_bar) system, which can be parameterized as a Breit-Wigner function with a mass of (3.35^{+0.01}_{-0.02}+-0.02)GeV/c^2 and a width of (0.07^{+0.04}_{-0.03}+-0.04)GeV/c^2. We measure the product of the corresponding decay branching fractions to be (3.87^{+0.77}_{-0.72}+-0.43+-1.01)x10^(-5)$ with a statistical significance of 6.2sigma. The errors are statistical, systematic, and that of the Lambda_c^+ -> pK-pi+ decay branching fraction.