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arXiv 1401.2158hep-ph
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轴加宽射流

Jet Shapes with the Broadening Axis

Andrew J. Larkoski, Duff Neill, Jesse Thaler

摘要:

加宽是一种经典的射流观测方法,它探测射流的横向动量结构。传统上,已经相对于推力轴测量了增宽,推力轴沿着(半球)射流动量对齐,以最小化射流内横向动量的矢量和。在本文中,我们主张测量相对于“加宽轴”,这是最小化的横向动量的标量和喷流的方向。这种方法消除了许多计算的复杂性所产生的反冲的领导部分子,和可观察到的喷流角度成为反冲时,使用增宽轴测量。我们推导出一个简单的因子分解定理的扩展轴观测值之间的推力和扩展的政权顺利插入。我们认为,同样的因式分解定理适用于两点能量关联函数以及基于“赢家通吃轴”的射流形状。使用扭结增宽轴,我们计算事件范围的角在e+e-碰撞与次领先的对数重算。定义喷流区域使用加宽轴,我们还计算了一个单一的喷流内的角度的全球范围内。我们发现很好的协议比较我们的计算都淋浴蒙特卡洛程序和自动化remation工具。我们给出了一个简短的历史观点上的拓宽轴,并建议的方式,拓宽轴观测值可用于在未来的大型强子对撞机射流子结构研究。

英文摘要:

Broadening is a classic jet observable that probes the transverse momentum structure of jets. Traditionally, broadening has been measured with respect to the thrust axis, which is aligned along the (hemisphere) jet momentum to minimize the vector sum of transverse momentum within a jet. In this paper, we advocate measuring broadening with respect to the "broadening axis", which is the direction that minimizes the scalar sum of transverse momentum within a jet. This approach eliminates many of the calculational complexities arising from recoil of the leading parton, and observables like the jet angularities become recoil-free when measured using the broadening axis. We derive a simple factorization theorem for broadening-axis observables which smoothly interpolates between the thrust-like and broadening-like regimes. We argue that the same factorization theorem holds for two-point energy correlation functions as well as for jet shapes based on a "winner-take-all axis". Using kinked broadening axes, we calculate event-wide angularities in e+e- collisions with next-to-leading logarithmic resummation. Defining jet regions using the broadening axis, we also calculate the global logarithms for angularities within a single jet. We find good agreement comparing our calculations both to showering Monte Carlo programs and to automated resummation tools. We give a brief historical perspective on the broadening axis and suggest ways that broadening-axis observables could be used in future jet substructure studies at the Large Hadron Collider.

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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