Multivariate discrimination and the Higgs+W/Z search
Multivariate discrimination and the Higgs+W/Z search
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DOI：
10.1007/jhep04(2011)069
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发表时间：
2010-10
影响因子：
5.4
通讯作者：
Jason Gallicchio;J. Huth;M. Kagan;M. Schwartz;K. Black;B. Tweedie
中科院分区：
文献类型：
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作者：
Jason Gallicchio;J. Huth;M. Kagan;M. Schwartz;K. Black;B. Tweedie
一个系统的方法优化多元判别式的开发和应用的重要例子轻希格斯玻色子搜索在Tevatron和大型强子对撞机。显著性改善特征（SIC），定义为切割或多元判别的信号效率除以背景效率的平方根，被证明是一个非常强大的可视化工具。SIC曲线显示了多变量判别式的数值不稳定性，随着变量数的增加而显示收敛性，并显示对最佳切割值的敏感性。对于我们的应用，我们集中在希格斯玻色子的生产与W或Z玻色子与不可约标准模型的背景，比较。我们探索了成千上万的实验动机，物理动机，和无动机的单变量判别式。沿着标准的运动变量，一些新的，如扭曲，应具有适用性的许多过程中描述。我们发现，一些单一的变量，如拉角，是弱判别，但当与其他人结合起来，他们提供了重要的边际改善。我们还发现，多个希格斯玻色子候选人的质量措施，如从温和和积极修剪喷流，结合起来时，可能会提供额外的鉴别能力。将我们的变量的显著性改善与最近的CDF和DIGITAL搜索中使用的变量进行比较，我们发现可能会有10-20%的显著性改善。我们的分析还表明，H+ W/Z通道在LHC上也是可行的，而不需要对W/Z横向动量进行硬切割。
A systematic method for optimizing multivariate discriminants is developed and applied to the important example of a light Higgs boson search at the Tevatron and the LHC. The Significance Improvement Characteristic (SIC), defined as the signal efficiency of a cut or multivariate discriminant divided by the square root of the background efficiency, is shown to be an extremely powerful visualization tool. SIC curves demonstrate numerical instabilities in the multivariate discriminants, show convergence as the number of variables is increased, and display the sensitivity to the optimal cut values. For our application, we concentrate on Higgs boson production in association with a W or Z boson withand compare to the irreducible standard model background,. We explore thousands of experimentally motivated, physically motivated, and unmotivated single variable discriminants. Along with the standard kinematic variables, a number of new ones, such as twist, are described which should have applicability to many processes. We find that some single variables, such as the pull angle, are weak discriminants, but when combined with others they provide important marginal improvement. We also find that multiple Higgs boson-candidate mass measures, such as from mild and aggressively trimmed jets, when combined may provide additional discriminating power. Comparing the significance improvement from our variables to those used in recent CDF and DØ searches, we find that a 10-20% improvement in significance againstis possible. Our analysis also suggests that the H+ W/Z channel withis also viable at the LHC, without requiring a hard cut on the W/Z transverse momentum.