The Born cross section and dressed cross section of e+e−→bb¯and the total hadronic cross section in e+e−annihilation in the bottomonium energy region are calculated based on the Rb values measured by the BaBar a...The Born cross section and dressed cross section of e+e−→bb¯and the total hadronic cross section in e+e−annihilation in the bottomonium energy region are calculated based on the Rb values measured by the BaBar and Belle experiments.The data are used to calculate the vacuum polarization factors in the bottomonium energy region,and to determine the resonant parameters of the vector bottomonium(-like)states Y(10750),Υ(5S),andΥ(6S).展开更多
Objective:This study is aimed at measuring the ripple of magnetic power supply of BEPCII and checking its effect to beam energy.Materials and methods:A sensor made of printed circuit board coils is designed and manufa...Objective:This study is aimed at measuring the ripple of magnetic power supply of BEPCII and checking its effect to beam energy.Materials and methods:A sensor made of printed circuit board coils is designed and manufactured.The sensor was inserted into a good area region of the magnetic field with the surface perpendicular to the field force lines.The change of the magnetic field would be detected according to Faraday’s law.Results:The experiment result indicates that the timedependent ripple of the magnetic field is in the magnitude of ppm.Conclusion:Such a small effect of the time-dependent ripplecan be negligibleto beam energy.展开更多
基金Supported in part by National Natural Science Foundation of China(NSFC)(11521505,11475187,11375206)Key Research Program of Frontier Sciences,CAS,(QYZDJ-SSW-SLH011)+1 种基金the CAS Center for Excellence in Particle Physics(CCEPP)and the Munich Institute for Astro-and Particle Physics(MIAPP)which is fun-ded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany's Excellence Strategy-EXC-2094-390783311。
文摘The Born cross section and dressed cross section of e+e−→bb¯and the total hadronic cross section in e+e−annihilation in the bottomonium energy region are calculated based on the Rb values measured by the BaBar and Belle experiments.The data are used to calculate the vacuum polarization factors in the bottomonium energy region,and to determine the resonant parameters of the vector bottomonium(-like)states Y(10750),Υ(5S),andΥ(6S).
文摘Objective:This study is aimed at measuring the ripple of magnetic power supply of BEPCII and checking its effect to beam energy.Materials and methods:A sensor made of printed circuit board coils is designed and manufactured.The sensor was inserted into a good area region of the magnetic field with the surface perpendicular to the field force lines.The change of the magnetic field would be detected according to Faraday’s law.Results:The experiment result indicates that the timedependent ripple of the magnetic field is in the magnitude of ppm.Conclusion:Such a small effect of the time-dependent ripplecan be negligibleto beam energy.
