Analytic three-loop QCD corrections to top-quark and semileptonic $b\to u$ decays
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| Main Authors: | , , , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866910422273097728 |
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| author | Chen, Long-Bin Li, Hai Tao Li, Zhao Wang, Jian Wang, Yefan Wu, Quan-feng |
| author_facet | Chen, Long-Bin Li, Hai Tao Li, Zhao Wang, Jian Wang, Yefan Wu, Quan-feng |
| contents | We present the first analytic results of N$^3$LO QCD corrections to the top-quark decay width. We focus on the dominant leading color contribution, which includes light-quark loops. At NNLO, this dominant contribution accounts for 95% of the total correction. By utilizing the optical theorem, the N$^3$LO corrections are related to the imaginary parts of the four-loop self-energy Feynman diagrams, which are calculated with differential equations. The results are expressed in terms of harmonic polylogarithms, enabling fast and accurate evaluation. The third-order QCD corrections decrease the LO decay width by 0.667%, and the scale uncertainty is reduced by half compared to the NNLO result. The most precise prediction for the top-quark width is now 1.321 GeV for $m_t=172.69$ GeV. Additionally, we obtain the third-order QCD corrections to the dilepton invariant mass spectrum and decay width in the semileptonic $b\to u$ transition. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2309_00762 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Analytic three-loop QCD corrections to top-quark and semileptonic $b\to u$ decays Chen, Long-Bin Li, Hai Tao Li, Zhao Wang, Jian Wang, Yefan Wu, Quan-feng High Energy Physics - Phenomenology High Energy Physics - Experiment We present the first analytic results of N$^3$LO QCD corrections to the top-quark decay width. We focus on the dominant leading color contribution, which includes light-quark loops. At NNLO, this dominant contribution accounts for 95% of the total correction. By utilizing the optical theorem, the N$^3$LO corrections are related to the imaginary parts of the four-loop self-energy Feynman diagrams, which are calculated with differential equations. The results are expressed in terms of harmonic polylogarithms, enabling fast and accurate evaluation. The third-order QCD corrections decrease the LO decay width by 0.667%, and the scale uncertainty is reduced by half compared to the NNLO result. The most precise prediction for the top-quark width is now 1.321 GeV for $m_t=172.69$ GeV. Additionally, we obtain the third-order QCD corrections to the dilepton invariant mass spectrum and decay width in the semileptonic $b\to u$ transition. |
| title | Analytic three-loop QCD corrections to top-quark and semileptonic $b\to u$ decays |
| topic | High Energy Physics - Phenomenology High Energy Physics - Experiment |
| url | https://arxiv.org/abs/2309.00762 |