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arXiv 2208.01293hep-phgr-qchep-th
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规范理论中的量子标度不变性及其在μ子产生中的应用

Quantum scale invariance in gauge theories and applications to muon production

Matthias Weißwange, Dumitru M. Ghilencea, Dominik Stöckinger

AI总结:

本文研究含紫外和红外发散的标度不变规范理论,证明两种SIR方法等价,并计算单圈重整化及μ子产生截面,表明红外极点不贡献新物理。

摘要:

我们讨论同时具有紫外(UV)与红外(IR)发散的(标度不变)规范理论中的量子标度不变性。首先,在使用标度不变正规化(SIR)的两种表面上不相关的方法中检验了它们的BRST不变性,随后证明这两种方法是等价的。其次,对于Abelian情形,我们讨论此类理论中存在的紫外与红外量子修正。我们给出了适合离壳Green函数计算的Feynman规则形式,以及它们的单圈重整化。这些信息随后被用于量子标度不变理论中μ子产生截面在单圈阶的计算。这样的理论不仅包含新的紫外极点,也包含红外极点。虽然紫外极点带来我们计算出的新的量子修正(以抵消项形式,有限或发散),但结果表明红外极点并不带来新的物理。红外量子修正,无论是有限的还是发散的,都以与传统处理红外发散方法中红外极点自身相消类似的方式相互抵消(在截面中,对虚修正和实修正求和之后)。因此,由SIR方案的标度不变解析延拓所诱导的渐逝相互作用不影响红外物理,这一点在μ子产生($e^+ e^- \ o μ^+μ^-$)截面的单圈计算中得到了说明。

英文摘要:

We discuss quantum scale invariance in (scale invariant) gauge theories with both ultraviolet (UV) and infrared (IR) divergences. Firstly, their BRST invariance is checked in two apparently unrelated approaches using a scale invariant regularisation (SIR). These approaches are then shown to be equivalent. Secondly, for the Abelian case we discuss both UV and IR quantum corrections present in such theories. We present the Feynman rules in a form suitable for offshell Green functions calculations, together with their one-loop renormalisation. This information is then used for the muon production cross section at one-loop in a quantum scale invariant theory. Such a theory contains not only new UV poles but also IR poles. While the UV poles bring new quantum corrections (in the form of counterterms), finite or divergent, that we compute, it is shown that the IR poles do not bring new physics. The IR quantum corrections, both finite and divergent, cancel out similarly to the way the IR poles themselves cancel in the traditional approach to IR divergences (in the cross section, after summing over virtual and real corrections). Hence, the evanescent interactions induced by the scale-invariant analytical continuation of the SIR scheme do not affect IR physics, as illustrated at one-loop for the muon production ($e^+ e^- \to μ^+μ^-$) cross section.

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