Y(4220)粒子的质量和宽度  

The mass and width of Y(4220)

作　　者：李春花 赵静[1] 岳崇兴[1] LI Chunhua;ZHAO Jing;YUE Chongxing(School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029, China)

机构地区：[1]辽宁师范大学物理与电子技术学院,辽宁大连116029

出　　处：《辽宁师范大学学报（自然科学版）》2021年第2期188-192,共5页Journal of Liaoning Normal University:Natural Science Edition

基　　金：国家自然科学基金资助项目(11805090)。

摘　　要：BESⅢ实验利用正负电子对撞质心能量s在3.773~4.7 GeV区间内采集79个能量点约9 fb^(-1)的数据对e^(+)e^(-)→π^(+)π^(-)J/ψ和π^(+)π^(-)hc的产生截面进行了精确测量,并观测到了新的类粲偶素Y(4220).随后BESⅢ实验对e^(+)e^(-)→_(ω)χ_(c0),π^(+)π^(-)ψ(2S),π^(+)D0D*^(-)^(+)c.c.,ηhc,ηJ/ψ,K^(+)K^(-)J/ψ的产生截面也进行了测量,同样在4.22 GeV附近发现了新粒子存在的迹象,并拟合截面分布提取了相应的质量和宽度.由于从不同过程测量到的质量和宽度相近,假设这些过程发现的是同一个粒子Y(4220),通过对这些过程测量到的粒子质量和宽度进行联合拟合,得到了高精度的Y(4220)粒子的质量和宽度.By using 79 energy points data collected between 3.773~4.7 GeV with a total luminosity of about 9 fb^(-1),BESⅢmeasured the cross sections of the processes e^(+)e^(-)→π^(+)π^(-)J/ψandπ^(+)π^(-)hc with high precision,and the distributions of the energy^(-)dependent cross sections show a new particle Y(4220)around 4.22 GeV.The mass and width of the particle is obtained by fitting the distributions of the cross sections with Breit^(-)Wigner functions.To further investigate the physics in this energy region,BESⅢalso measured the cross sections of the processes e^(+)e^(-)→_(ω)χ_(c0),π^(+)π^(-)ψ(2S),π^(+)D0D*^(-)^(+)c.c.,ηhc,ηJ/ψ,Κ^(+)Κ^(-)J/ψ.A similar enhancement was observed around 4.22 GeV in these processes.The masses and widths are also extracted from the distributions of the energy^(-)dependent cross sections.Since the masses and widths measured in different process are close,we assume that what found in these processes are the same particle,and do a combined fit to the masses and widths obtained from these measurements to extract the resonant parameters of the particle with higher precision.

关 键 词：Y(4220) 质量 宽度 截面 

分 类 号：O572.2[理学—粒子物理与原子核物理]