Deconstructed hypercharge: a natural model of flavour
Abstract The flavour puzzle is one of the greatest mysteries in particle physics. A ‘flavour deconstruction’ of the electroweak gauge symmetry, by promoting at least part of it to the product of a third family factor (under which the Higgs is charged) times a light family factor, allows one to addre...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2023-11-01
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| Series: | Journal of High Energy Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/JHEP11(2023)100 |
| _version_ | 1797199730941362176 |
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| author | Joe Davighi Ben A. Stefanek |
| author_facet | Joe Davighi Ben A. Stefanek |
| author_sort | Joe Davighi |
| collection | DOAJ |
| description | Abstract The flavour puzzle is one of the greatest mysteries in particle physics. A ‘flavour deconstruction’ of the electroweak gauge symmetry, by promoting at least part of it to the product of a third family factor (under which the Higgs is charged) times a light family factor, allows one to address the flavour puzzle at a low scale due to accidentally realised U(2)5 flavour symmetries. The unavoidable consequence is new heavy gauge bosons with direct couplings to the Higgs, threatening the stability of the electroweak scale. In this work, we propose a UV complete model of flavour based on deconstructing only hypercharge. We find that the model satisfies finite naturalness criteria, benefiting from the smallness of the hypercharge gauge coupling in controlling radiative Higgs mass corrections and passing phenomenological bounds. Our setup allows one to begin explaining flavour at the TeV scale, while dynamics solving the large hierarchy problem can lie at a higher scale up to around 10 TeV — without worsening the unavoidable little hierarchy problem. The low-energy phenomenology of the model is dominated by a single Z′ gauge boson with chiral and flavour non-universal couplings, with mass as light as a few TeV thanks to the U(2)5 symmetry. The natural parameter space of the model will be probed by the HL-LHC and unavoidably leads to large positive shifts in the W-boson mass, as well as an enhancement in B $$ \mathcal{B} $$ (B s,d → μ + μ −). Finally, we show that a future electroweak precision machine such as FCC-ee easily has the reach to fully exclude the model. |
| first_indexed | 2024-03-09T15:31:46Z |
| format | Article |
| id | doaj.art-0a0bd87c7d524cb4a5e761abf996ff79 |
| institution | Directory Open Access Journal |
| issn | 1029-8479 |
| language | English |
| last_indexed | 2024-04-24T07:20:24Z |
| publishDate | 2023-11-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj.art-0a0bd87c7d524cb4a5e761abf996ff792024-04-21T11:05:11ZengSpringerOpenJournal of High Energy Physics1029-84792023-11-0120231113210.1007/JHEP11(2023)100Deconstructed hypercharge: a natural model of flavourJoe Davighi0Ben A. Stefanek1Physik-Institut, Universität ZürichPhysik-Institut, Universität ZürichAbstract The flavour puzzle is one of the greatest mysteries in particle physics. A ‘flavour deconstruction’ of the electroweak gauge symmetry, by promoting at least part of it to the product of a third family factor (under which the Higgs is charged) times a light family factor, allows one to address the flavour puzzle at a low scale due to accidentally realised U(2)5 flavour symmetries. The unavoidable consequence is new heavy gauge bosons with direct couplings to the Higgs, threatening the stability of the electroweak scale. In this work, we propose a UV complete model of flavour based on deconstructing only hypercharge. We find that the model satisfies finite naturalness criteria, benefiting from the smallness of the hypercharge gauge coupling in controlling radiative Higgs mass corrections and passing phenomenological bounds. Our setup allows one to begin explaining flavour at the TeV scale, while dynamics solving the large hierarchy problem can lie at a higher scale up to around 10 TeV — without worsening the unavoidable little hierarchy problem. The low-energy phenomenology of the model is dominated by a single Z′ gauge boson with chiral and flavour non-universal couplings, with mass as light as a few TeV thanks to the U(2)5 symmetry. The natural parameter space of the model will be probed by the HL-LHC and unavoidably leads to large positive shifts in the W-boson mass, as well as an enhancement in B $$ \mathcal{B} $$ (B s,d → μ + μ −). Finally, we show that a future electroweak precision machine such as FCC-ee easily has the reach to fully exclude the model.https://doi.org/10.1007/JHEP11(2023)100Theories of FlavourFlavour SymmetriesNew Gauge InteractionsSpecific BSM Phenomenology |
| spellingShingle | Joe Davighi Ben A. Stefanek Deconstructed hypercharge: a natural model of flavour Journal of High Energy Physics Theories of Flavour Flavour Symmetries New Gauge Interactions Specific BSM Phenomenology |
| title | Deconstructed hypercharge: a natural model of flavour |
| title_full | Deconstructed hypercharge: a natural model of flavour |
| title_fullStr | Deconstructed hypercharge: a natural model of flavour |
| title_full_unstemmed | Deconstructed hypercharge: a natural model of flavour |
| title_short | Deconstructed hypercharge: a natural model of flavour |
| title_sort | deconstructed hypercharge a natural model of flavour |
| topic | Theories of Flavour Flavour Symmetries New Gauge Interactions Specific BSM Phenomenology |
| url | https://doi.org/10.1007/JHEP11(2023)100 |
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