A study of W+W−γ events at LEP
A study of W+W−γ events at LEP
复制标题
DOI：
10.1016/j.physletb.2003.10.063
复制
发表时间：
2003-09
影响因子：
4.4
通讯作者：
The Opal Collaboration;G. Abbiendi;E. al.
中科院分区：
文献类型：
--
作者：
The Opal Collaboration;G. Abbiendi;E. al.
本文研究了LEP上e{sup+}e{sup-}碰撞产生的W{sup+}W{sup-}事件伴随着硬光子辐射E{Sub{Gamma}>；2.5GeV。符合两个壳上W玻色子和一个孤立光子的事件选自记录在180GeV；S和209GeV的681PB数据。从光子能量大于2.5GeV的187个W{sup+}W{sup-}{Gamma}候选者的样本中，在S的5个值处测定了W{sup+}W{sup-}{Gamma}截面，结果与标准模型的预期相符。平均所有能量，观测截面与标准模型期望值的比率为R(DATA/SM)=0.99+/-0.09+/-0.04，其中误差分别代表统计和系统的不确定性。这些数据对在LEP测量W玻色子质量的相关O({α})系统不确定度提供了约束。最后，数据被用来得出对W{sup+}W{sup-}{Gamma}和W{sup+}W{sup-}Z{sup-2}{Gamma}顶点的可能反常贡献的95%置信度上限：-0.020 GeV{sup-2}<；a{sub0}{lambda}{sup 2}<；0.020 GeV{sup-2}，-0.053 GeV{sup-2}<；a{subc}{lambda}{sup 2}<；0.037 GeV{sup-2}，-0.16GeV{sup-2}<；a{subn}{lambda}{sup 2}<；0.15GeV{sup-2}，其中{lambda}表示新物理的能量标度，a{sub0}，a{subc}和a{subn}是无量纲耦合常数。
A study of W{sup +}W{sup -} events accompanied by hard photon radiation, E{sub {gamma}}>2.5 GeV, produced in e{sup +}e{sup -} collisions at LEP is presented. Events consistent with being two on-shell W-bosons and an isolated photon are selected from 681 pb{sup -1} of data recorded at 180 GeV<s<209 GeV. From the sample of 187 selected W{sup +}W{sup -}{gamma} candidates with photon energies greater than 2.5 GeV, the W{sup +}W{sup -}{gamma} cross-section is determined at five values of s. The results are consistent with the Standard Model expectation. Averaging over all energies, the ratio of the observed cross-section to the Standard Model expectation is R(data/SM)=0.99+/-0.09+/-0.04, where the errors represent the statistical and systematic uncertainties respectively. These data provide constraints on the related O({alpha}) systematic uncertainties on the measurement of the W-boson mass at LEP. Finally, the data are used to derive 95% confidence level upper limits on possible anomalous contributions to the W{sup +}W{sup -}{gamma}{gamma} and W{sup +}W{sup -}Z{sup 0}{gamma} vertices: -0.020 GeV{sup -2}<a{sub 0}{lambda}{sup 2}<0.020 GeV{sup -2},-0.053 GeV{sup -2}<a{sub c}{lambda}{sup 2}<0.037 GeV{sup -2},-0.16 GeV{sup -2}<a{sub n}{lambda}{sup 2}<0.15 GeV{sup -2}, where {lambda} represents the energy scale for new physics and a{sub 0}, a{sub c} and a{sub n} are dimensionless coupling constants.