关于X(3915)粒子共振参数的研究

Study of the resonant parameters of X(3915)

正负电子对撞实验Belle和BABAR通过双光子过程γγ→ωJ/ψ和B介子衰变过程B→ΚωJ/ψ先后观测到了类粲偶素粒子X(3915)并确定了其作为S波共振态的质量和宽度.利用这些实验测量结果,利用最小二乘法对Belle和BABAR实验测量的ωJ/ψ不变质量分布进行联合拟合,得到X(3915)的质量和宽度分别为M=(3917.5±1.1)MeV/c 2和Γ=(17.6±2.6)MeV.拟合结果与各实验测量结果符合但精度更高.

The X(3915) was observed by Belle and BABAR experiments in the processes γγ→ωJ/ψ and B→ωJ/ψ , and the resonant parameters are provided by assuming X(3915) as a S -wave Breit-Wigner resonance. We perform a simultaneous χ 2 fit to the distributions of invariant mass of ωJ/ψ measured by Belle and BABAR to extract the mass and width of X(3915). The determined values are M =(3 917.5±1.1) MeV/c 2 and Γ =(17.6±2.6) MeV, respectively. The fitting results are in good agreement with the experimental measurement but with higher precision.