北京谱仪R值测量中的初态辐射修正

Initial State Radiative Correction in R Measurement at BES

从R值测量实验的角度讨论了e+ e- 碰撞通过单光子湮没产生强子截面的辐射修正 ,分析了 3种典型的计算方案 .在BEPC/BES上运行的 2— 5GeV能区 ,不同方案给出的辐射修正因子理论值 ( 1 +δ)的差别大约是 1 %— 2 % ,而每一方案计算中由于各种不确定因素带来的有效辐射修正因子 ( 1 +δobs)的总误差约为 2 %— 3% .

Three typical schemes of the initial state radiative correction in e +e - collision through single photon annihilation were reviewed, and the numerical results were calculated in the energy region of 2—5GeV. The differences of the theoretical values of radiative correction factors (1+δ) are about 1%—2%. The uncertainty of the effective (1+δ obs ) is estimated to be about 2%—3%.