论文标题
在三喷射区域中的$ e^+e^ - $ SHAPE变量的线性功率更正
Linear power corrections to $e^+e^-$ shape variables in the three-jet region
论文作者
论文摘要
我们使用Abelian模型来研究由红外Renormalons引起的线性功率校正，并影响$ E^+E^ - $ nihihitation in Hadroons中的事件形状。虽然先前的研究探索了两喷射区域的功率校正，但在本文中，我们关注的是三射流区域，这是确定强耦合常数的最相关的区域。我们表明，对于一类宽类形状变量，可以以分析性形式写入线性功率校正，该形式涉及一个可分析的函数，该函数表征了当发出软part顿时形状变量的变化，并且是恒定的通用因子。这种通用因子与早期文献中引入的所谓米兰因子成正比，以描述两射流区域中的线性功率校正。我们发现，两射流和三射流区域中的功率校正是不同的，这一结果必然会对确定事件形状的强耦合常数产生重要的后果。为了进一步说明本文开发的方法的力量，我们为$ c $ - 参数的领先功率校正提供明确的分析表达式，并为任意$ n $的$ n $ jet区域中的推力分布提供，尽管在阿贝尔模型中。
We use an abelian model to study linear power corrections which arise from infrared renormalons and affect event shapes in $e^+e^-$ annihilation into hadrons. While previous studies explored power corrections in the two-jet region, in this paper we focus on the three-jet region, which is the most relevant one for the determination of the strong coupling constant. We show that for a broad class of shape variables, linear power corrections can be written in a factorised form, that involves an analytically-calculable function, that characterises changes in the shape variable when a soft parton is emitted, and a constant universal factor. This universal factor is proportional to the so-called Milan factor, introduced in earlier literature to describe linear power corrections in the two-jet region. We find that the power corrections in the two-jet and in the three-jet regions are different, a result which is bound to have important consequences for the determination of the strong coupling constant from event shapes. As a further illustration of the power of the approach developed in this paper, we provide explicit analytic expressions for the leading power corrections to the $C$-parameter and the thrust distributions in the $N$-jet region for arbitrary $N$, albeit in the abelian model.
