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arXiv 1701.01464hep-ph
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包含观测量的阈值和横动量联合重算

Combined threshold and transverse momentum resummation for inclusive observables

Claudio Muselli, Stefano Forte, Giovanni Ridolfi

摘要:

本文给出了微扰QCD中无色末态横动量分布的一个组合表达式,表示为横动量pt和标度变量x的函数。它的表达式满足三个条件:对于固定的x,在pt-> 0的极限内,它可简化为标准的横向动量重算到任何所需的对数阶,直到pt中的功率抑制修正;对于固定的pt,在x-> 1的极限内,它可简化为阈值重算到任何所需的对数阶,直到1-x中的功率抑制修正;在对横向动量积分时,它再现了在阈值x>1极限中的任何给定对数级的总交叉的再确认。它的主要成分,我们的主要新结果,是一个修改后的形式的横向动量remation,这导致阈值remation后,积分超过pt,并为此我们提供了一个简单的封闭形式的解析表达式在Fourier-Mellin(b,N)空间。对于有效场论极限下胶子聚变中Higgs产生的具体情况,我们给出了NNLL阶的显式系数。我们的结果允许通过阈值重定的横向动量分布的一个系统的改进,适用于所有的PT,并阐明了横向动量重定和阈值重定之间的关系在包容性的水平,特别是通过微扰QCD内提供一个简单的推导所谓的SCET的共线异常的主要后果。

英文摘要:

We present a combined resummation for the transverse momentum distribution of a colorless final state in perturbative QCD, expressed as a function of transverse momentum pt and the scaling variable x. Its expression satisfies three requirements: it reduces to standard transverse momentum resummation to any desired logarithmic order in the limit pt-> 0 for fixed x, up to power suppressed corrections in pt; it reduces to threshold resummation to any desired logarithmic order in the limit x-> 1 for fixed pt, up to power suppressed correction in 1-x; upon integration over transverse momentum it reproduces the resummation of the total cross cross at any given logarithmic order in the threshold x->1 limit. Its main ingredient, and our main new result, is a modified form of transverse momentum resummation, which leads to threshold resummation upon integration over pt, and for which we provide a simple closed-form analytic expression in Fourier-Mellin (b,N) space. We give explicit coefficients up to NNLL order for the specific case of Higgs production in gluon fusion in the effective field theory limit. Our result allows for a systematic improvement of the transverse momentum distribution through threshold resummation which holds for all pt, and elucidates the relation between transverse momentum resummation and threshold resummation at the inclusive level, specifically by providing within perturbative QCD a simple derivation of the main consequence of the so-called collinear anomaly of SCET.

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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