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arXiv 2012.00622hep-ph
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对称3喷注极限中的$C$参数强子化和对$α_s$拟合的影响

$C$-parameter hadronisation in the symmetric 3-jet limit and impact on $α_s$ fits

Gionata Luisoni, Pier Francesco Monni, Gavin P. Salam

摘要:

强子化修正是从轻子对撞机事件形状分布中提取强耦合常数($α_s$)的关键。虽然它们的动力学不能用微扰方法严格理解,但它们对物理观测量的主要影响可以在对软辐射发射敏感的奇异配置中估计。一些事件形状变量的微分分布,特别是$C$参数,具有两个这样的奇点。我们分析计算领先的非微扰修正对称三喷流极限的$C$参数,并发现它不同于两个喷流极限的已知结果的两个以上的因素。我们估计这一结果对强耦合提取的影响,考虑到一系列的功能,以插值的强子化校正之间的区域2和3-喷气限制。从ALEPH和JADE拟合数据,我们发现,大多数插值选择增加提取的$α_s$,与标准拟合的效果高达$4\%$。这为某些事件形状$α_s$拟合与世界平均值之间长期存在的差异带来了新的视角。

英文摘要:

Hadronisation corrections are crucial in extractions of the strong coupling constant ($α_s$) from event-shape distributions at lepton colliders. Although their dynamics cannot be understood rigorously using perturbative methods, their dominant effect on physical observables can be estimated in singular configurations sensitive to the emission of soft radiation. The differential distributions of some event-shape variables, notably the $C$ parameter, feature two such singular points. We analytically compute the leading non-perturbative correction in the symmetric three-jet limit for the $C$ parameter, and find that it differs by more than a factor of two from the known result in the two-jet limit. We estimate the impact of this result on strong coupling extractions, considering a range of functions to interpolate the hadronisation correction in the region between the 2 and 3-jet limits. Fitting data from ALEPH and JADE, we find that most interpolation choices increase the extracted $α_s$, with effects of up to $4\%$ relative to standard fits. This brings a new perspective on the long-standing discrepancy between certain event-shape $α_s$ fits and the world average.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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