Rare top-quark decays $$t \rightarrow cg(g)$$ t → c g ( g ) in the aligned two-Higgs-doublet model
Abstract We update the Standard Model (SM) predictions for the branching ratios of the rare top-quark decays $$t \rightarrow cg(g)$$ t → c g ( g ) , and evaluate the maximum rates that can be reached in the aligned as well as in the four conventional two-Higgs-doublet models (2HDMs) with $$\mathcal...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2022-10-01
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| Series: | European Physical Journal C: Particles and Fields |
| Online Access: | https://doi.org/10.1140/epjc/s10052-022-10815-x |
| _version_ | 1811226640216227840 |
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| author | Fang-Min Cai Shuichiro Funatsu Xin-Qiang Li Ya-Dong Yang |
| author_facet | Fang-Min Cai Shuichiro Funatsu Xin-Qiang Li Ya-Dong Yang |
| author_sort | Fang-Min Cai |
| collection | DOAJ |
| description | Abstract We update the Standard Model (SM) predictions for the branching ratios of the rare top-quark decays $$t \rightarrow cg(g)$$ t → c g ( g ) , and evaluate the maximum rates that can be reached in the aligned as well as in the four conventional two-Higgs-doublet models (2HDMs) with $$\mathcal {Z}_2$$ Z 2 symmetries. Taking into account the relevant constraints on the model parameters resulting from a global fit obtained at the $$95.5\%$$ 95.5 % confidence level, we find that the branching ratios of $$t \rightarrow cg$$ t → c g and $$t \rightarrow cgg$$ t → c g g decays can reach up to $$3.36\times 10^{-9}$$ 3.36 × 10 - 9 and $$2.95\times 10^{-9}$$ 2.95 × 10 - 9 respectively, being therefore of the same order, in the aligned 2HDM (A2HDM). This is obviously different from the SM case, where the predicted branching ratio of the three-body decay $$t \rightarrow cgg$$ t → c g g is about two orders of magnitude larger than that of the two-body decay $$t \rightarrow cg$$ t → c g . On the other hand, compared with the SM predictions, no significant enhancements are observed in the four conventional 2HDMs with $$\mathcal {Z}_2$$ Z 2 symmetries for the branching ratios of these two decays. Nevertheless, the predicted branching ratios of $$t \rightarrow cg$$ t → c g and $$t \rightarrow cgg$$ t → c g g decays in the A2HDM are still out of the expected sensitivities of the future high-luminosity Large Hadron Collider and the Future Circular Collider in hadron-hadron mode. |
| first_indexed | 2024-04-12T09:28:34Z |
| format | Article |
| id | doaj.art-f4d9637ab6f6425ba7f941b33306375c |
| institution | Directory Open Access Journal |
| issn | 1434-6052 |
| language | English |
| last_indexed | 2024-04-12T09:28:34Z |
| publishDate | 2022-10-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | European Physical Journal C: Particles and Fields |
| spelling | doaj.art-f4d9637ab6f6425ba7f941b33306375c2022-12-22T03:38:26ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60522022-10-01821013110.1140/epjc/s10052-022-10815-xRare top-quark decays $$t \rightarrow cg(g)$$ t → c g ( g ) in the aligned two-Higgs-doublet modelFang-Min Cai0Shuichiro Funatsu1Xin-Qiang Li2Ya-Dong Yang3Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOE), Central China Normal UniversityInstitute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOE), Central China Normal UniversityInstitute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOE), Central China Normal UniversitySchool of Physics and Microelectronics, Zhengzhou UniversityAbstract We update the Standard Model (SM) predictions for the branching ratios of the rare top-quark decays $$t \rightarrow cg(g)$$ t → c g ( g ) , and evaluate the maximum rates that can be reached in the aligned as well as in the four conventional two-Higgs-doublet models (2HDMs) with $$\mathcal {Z}_2$$ Z 2 symmetries. Taking into account the relevant constraints on the model parameters resulting from a global fit obtained at the $$95.5\%$$ 95.5 % confidence level, we find that the branching ratios of $$t \rightarrow cg$$ t → c g and $$t \rightarrow cgg$$ t → c g g decays can reach up to $$3.36\times 10^{-9}$$ 3.36 × 10 - 9 and $$2.95\times 10^{-9}$$ 2.95 × 10 - 9 respectively, being therefore of the same order, in the aligned 2HDM (A2HDM). This is obviously different from the SM case, where the predicted branching ratio of the three-body decay $$t \rightarrow cgg$$ t → c g g is about two orders of magnitude larger than that of the two-body decay $$t \rightarrow cg$$ t → c g . On the other hand, compared with the SM predictions, no significant enhancements are observed in the four conventional 2HDMs with $$\mathcal {Z}_2$$ Z 2 symmetries for the branching ratios of these two decays. Nevertheless, the predicted branching ratios of $$t \rightarrow cg$$ t → c g and $$t \rightarrow cgg$$ t → c g g decays in the A2HDM are still out of the expected sensitivities of the future high-luminosity Large Hadron Collider and the Future Circular Collider in hadron-hadron mode.https://doi.org/10.1140/epjc/s10052-022-10815-x |
| spellingShingle | Fang-Min Cai Shuichiro Funatsu Xin-Qiang Li Ya-Dong Yang Rare top-quark decays $$t \rightarrow cg(g)$$ t → c g ( g ) in the aligned two-Higgs-doublet model European Physical Journal C: Particles and Fields |
| title | Rare top-quark decays $$t \rightarrow cg(g)$$ t → c g ( g ) in the aligned two-Higgs-doublet model |
| title_full | Rare top-quark decays $$t \rightarrow cg(g)$$ t → c g ( g ) in the aligned two-Higgs-doublet model |
| title_fullStr | Rare top-quark decays $$t \rightarrow cg(g)$$ t → c g ( g ) in the aligned two-Higgs-doublet model |
| title_full_unstemmed | Rare top-quark decays $$t \rightarrow cg(g)$$ t → c g ( g ) in the aligned two-Higgs-doublet model |
| title_short | Rare top-quark decays $$t \rightarrow cg(g)$$ t → c g ( g ) in the aligned two-Higgs-doublet model |
| title_sort | rare top quark decays t rightarrow cg g t c g g in the aligned two higgs doublet model |
| url | https://doi.org/10.1140/epjc/s10052-022-10815-x |
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