QED corrections to parton distributions and Altarelli–Parisi splitting functions in the polarized case

IF 4.2 2区物理与天体物理 Q2 PHYSICS, PARTICLES & FIELDS

The European Physical Journal C Pub Date : 2023-08-06 DOI:10.1140/epjc/s10052-023-11871-7

Daniel de Florian, Lucas Palma Conte

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引用次数: 0

Abstract

We discuss the effect of QED corrections in the evolution of polarized parton distributions. We solve the corresponding evolution equations exactly to \({\mathcal {O}}(\alpha )\) and \({\mathcal {O}}(a_{\textrm{S}}^2)\) in Mellin N-space, extending the available techniques for pure QCD evolution. To accomplish this, we introduce, for the first time, the Altarelli–Parisi polarized kernels at LO in QED. Furthermore, we perform a phenomenological analysis of the QED effects on polarized parton distributions (pPDFs), proposing different scenarios for the polarized photon density. Finally, we quantify the impact of the corresponding QED contributions to the polarized structure function \(g_1\). We show that the relative corrections to both the pPDFs and the \(g_1\) structure function are approximately at the few percent level, which is the order of magnitude expected considering the value of \(\alpha \).

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极化情况下parton分布和Altarelli-Parisi分裂函数的QED校正

讨论了QED修正对极化部分子分布演化的影响。我们在Mellin n空间中精确地求解了相应的演化方程\({\mathcal {O}}(\alpha )\)和\({\mathcal {O}}(a_{\textrm{S}}^2)\)，扩展了纯QCD演化的可用技术。为了实现这一目标，我们首次在QED的LO中引入了Altarelli-Parisi极化核。此外，我们对QED对极化部分子分布(pPDFs)的影响进行了现象学分析，提出了极化光子密度的不同情况。最后，我们量化了相应的QED贡献对极化结构函数\(g_1\)的影响。我们表明，ppdf和\(g_1\)结构函数的相对修正大约在几个百分点的水平上，考虑到\(\alpha \)的值，这是预期的数量级。

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来源期刊

The European Physical Journal C 物理-物理：粒子与场物理

CiteScore

8.10

自引率

15.90%

发文量

1008

审稿时长

2-4 weeks

期刊介绍： Experimental Physics I: Accelerator Based High-Energy Physics Hadron and lepton collider physics Lepton-nucleon scattering High-energy nuclear reactions Standard model precision tests Search for new physics beyond the standard model Heavy flavour physics Neutrino properties Particle detector developments Computational methods and analysis tools Experimental Physics II: Astroparticle Physics Dark matter searches High-energy cosmic rays Double beta decay Long baseline neutrino experiments Neutrino astronomy Axions and other weakly interacting light particles Gravitational waves and observational cosmology Particle detector developments Computational methods and analysis tools Theoretical Physics I: Phenomenology of the Standard Model and Beyond Electroweak interactions Quantum chromo dynamics Heavy quark physics and quark flavour mixing Neutrino physics Phenomenology of astro- and cosmoparticle physics Meson spectroscopy and non-perturbative QCD Low-energy effective field theories Lattice field theory High temperature QCD and heavy ion physics Phenomenology of supersymmetric extensions of the SM Phenomenology of non-supersymmetric extensions of the SM Model building and alternative models of electroweak symmetry breaking Flavour physics beyond the SM Computational algorithms and tools...etc.