Measurement of event shape distributions and moments in e + e $^-\rightarrow \mathrm{hadrons}$ at 91-209 GeV and a determination of $\ensuremath{\alpha_{\mathrm{s}}}$
Measurement of event shape distributions and moments in e + e $^-\rightarrow \mathrm{hadrons}$ at 91-209 GeV and a determination of $\ensuremath{\alpha_{\mathrm{s}}}$
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DOI：
10.1140/epjc/s2005-02120-6
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发表时间：
2005-03
期刊：
影响因子：
--
通讯作者：
The Opal Collaboration
中科院分区：
文献类型：
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作者：
The Opal Collaboration
我们从91GeV到209GeV质心能量下的e+e湮没数据研究了强子事件。给出了各能级的事件形状可观量及其力矩的分布，并与QCD蒙特卡罗模型进行了比较。从事件的形状分布中提取强耦合，并用能量尺度检验强耦合的演化。计算结果与QCD的预期运行结果一致。综合所有数据，确定的值为$$\ensuremath{\alpha_{\mathrm{s}}}\ensuremath{M_{\mathrm{Z}}}=0.1191\pm0.0005\mathm{(统计)}\pm0.0010\mathm{(Ext.)}\pm0.0011\mathm{(hadr.)}\pm0.0044\mathm{(theo.)}\，。$$矩的能量演化也被用来确定的值，误差略大：$\EnsureMath{\Alpha_{\Mathrm{S}\EnsureMath{M_{\Mathrm{Z}=0.1223\pm 0.0005(\mathm{stat.})\pm 0.0014(\mathm{exp.})\pm 0.0016(\mathrm{hadr.})^{+0.0054}_{-0.0036}(\mathrm{theo.})$.
We have studied hadronic events from e+e-annihilation data at centre-of-mass energies from 91 to 209 GeV. We present distributions of event shape observables and their moments at each energy and compare with QCD Monte Carlo models. From the event shape distributions we extract the strong couplingand test its evolution with energy scale. The results are consistent with the running ofexpected from QCD. Combining all data, the value ofis determined to be $$ \ensuremath{\alpha_{\mathrm{s}}}\ensuremath{M_{\mathrm{Z}}} = 0.1191 \pm0.0005 \mathrm{(stat.)} \pm0.0010\mathrm{(expt.)} \pm0.0011 \mathrm{(hadr.)} \pm0.0044 \mathrm{(theo.)}\,. $$ The energy evolution of the moments is also used to determine a value ofwith slightly larger errors: $\ensuremath{\alpha_{\mathrm{s}}} \ensuremath{M_{\mathrm{Z}}}=0.1223\pm 0.0005(\mathrm{stat.})\pm 0.0014(\mathrm{expt.})\pm 0.0016(\mathrm{hadr.})^{+0.0054}_{-0.0036}(\mathrm{theo.})$.