First lattice QCD calculation of semileptonic decays of charmed-strange baryonsΞc

While the standard model is the most successful theory to describe all the interactions and constituents of elementary particle physics,it has been constantly scrutinized for over four decades.Weak decays of charm quarks can be used to measure the coupling strength between quarks in different families and serve as an ideal probe for CP violation.As the lowest charm-strange baryons with three different flavors,Ξ;baryons(composed of csu or csd)have been extensively studied in experiments.In this study,we use state-of-the-art lattice QCD techniques to generate 2+1 clover fermion ensembles with two lattice spacings,a=(0.108,0.080 fm).Then,we present the first ab-initio lattice QCD calculation of the Ξ;→Ξ form factors.Our theoretical results for the Ξc→Ξl;v;decay widths are consistent with and approximately two times more precise than the latest measurements by the ALICE and Belle collaborations.Based on the latest experimental measurements,we independently obtain the quark-mixing matrix element |V;|,which is in good agreement with results from other theoretical approaches.     

脉冲熔融法测定金属及陶瓷中氧、氮含量的研究进展

脉冲熔融法已广泛用于金属及陶瓷中氧、氮含量的测定.然而,国内关于相关设备的研究报道较少,在实际分析中,主要依据条件试验确定最佳参数,依赖加标回收保证准确度,缺少必要的理论研究及辅助方法验证检测结果.国外相关研究比较深入,设备、理论研究以及辅助方法应用均不乏亮点.基于此,系统介绍了设备,特别是检测系统、气路系统的改进,石...