The SM expected branching ratio for h → γγ and an excess for h → Zγ
Abstract The recent measurements of h → Zγ from ATLAS and CMS show an excess of the signal strength μ Z = σ · B obs / σ · B SM $$ {\left(\sigma \cdotp \mathcal{B}\right)}_{\textrm{obs}}/{\left(\sigma \cdotp \mathcal{B}\right)}_{\textrm{SM}} $$ = 2.2 ± 0.7, normalized as 1 in the standard model (SM)....
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| Format: | Article |
| Language: | English |
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SpringerOpen
2024-10-01
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| Series: | Journal of High Energy Physics |
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| Online Access: | https://doi.org/10.1007/JHEP10(2024)135 |
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| author | Xiao-Gang He Zhong-Lv Huang Ming-Wei Li Chia-Wei Liu |
| author_facet | Xiao-Gang He Zhong-Lv Huang Ming-Wei Li Chia-Wei Liu |
| author_sort | Xiao-Gang He |
| collection | DOAJ |
| description | Abstract The recent measurements of h → Zγ from ATLAS and CMS show an excess of the signal strength μ Z = σ · B obs / σ · B SM $$ {\left(\sigma \cdotp \mathcal{B}\right)}_{\textrm{obs}}/{\left(\sigma \cdotp \mathcal{B}\right)}_{\textrm{SM}} $$ = 2.2 ± 0.7, normalized as 1 in the standard model (SM). If confirmed, it would be a signal of new physics (NP) beyond the SM. We study NP explanation for this excess. In general, for a given model, it also affects the process h → γγ. Since the measured branching ratio for this process agrees well with the SM prediction, the model is severely constrained. We find that a minimally fermion singlets and doublet extended NP model can explain simultaneously the current data for h → Zγ and h → γγ. There are two solutions. Although both solutions enhance the amplitude of h → Zγ to the observed one, in one of the solutions the amplitude of h → γγ flips sign to give the observed branching ratio. This seems to be a contrived solution although cannot be ruled out simply using branching ratio measurements alone. However, we find another solution that naturally enhances h → Zγ to the measured value, but keeps the amplitude of h → γγ close to its SM prediction. We also comment on the phenomenology associated with these new fermions. |
| format | Article |
| id | doaj-art-026ba2c4ccef4c3d9d33a1b8b7283184 |
| institution | OA Journals |
| issn | 1029-8479 |
| language | English |
| publishDate | 2024-10-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj-art-026ba2c4ccef4c3d9d33a1b8b72831842025-08-20T02:31:04ZengSpringerOpenJournal of High Energy Physics1029-84792024-10-0120241011510.1007/JHEP10(2024)135The SM expected branching ratio for h → γγ and an excess for h → ZγXiao-Gang He0Zhong-Lv Huang1Ming-Wei Li2Chia-Wei Liu3Tsung-Dao Lee Institute, Shanghai Jiao Tong UniversityTsung-Dao Lee Institute, Shanghai Jiao Tong UniversityTsung-Dao Lee Institute, Shanghai Jiao Tong UniversityTsung-Dao Lee Institute, Shanghai Jiao Tong UniversityAbstract The recent measurements of h → Zγ from ATLAS and CMS show an excess of the signal strength μ Z = σ · B obs / σ · B SM $$ {\left(\sigma \cdotp \mathcal{B}\right)}_{\textrm{obs}}/{\left(\sigma \cdotp \mathcal{B}\right)}_{\textrm{SM}} $$ = 2.2 ± 0.7, normalized as 1 in the standard model (SM). If confirmed, it would be a signal of new physics (NP) beyond the SM. We study NP explanation for this excess. In general, for a given model, it also affects the process h → γγ. Since the measured branching ratio for this process agrees well with the SM prediction, the model is severely constrained. We find that a minimally fermion singlets and doublet extended NP model can explain simultaneously the current data for h → Zγ and h → γγ. There are two solutions. Although both solutions enhance the amplitude of h → Zγ to the observed one, in one of the solutions the amplitude of h → γγ flips sign to give the observed branching ratio. This seems to be a contrived solution although cannot be ruled out simply using branching ratio measurements alone. However, we find another solution that naturally enhances h → Zγ to the measured value, but keeps the amplitude of h → γγ close to its SM prediction. We also comment on the phenomenology associated with these new fermions.https://doi.org/10.1007/JHEP10(2024)135Higgs PropertiesSpecific BSM Phenomenology |
| spellingShingle | Xiao-Gang He Zhong-Lv Huang Ming-Wei Li Chia-Wei Liu The SM expected branching ratio for h → γγ and an excess for h → Zγ Journal of High Energy Physics Higgs Properties Specific BSM Phenomenology |
| title | The SM expected branching ratio for h → γγ and an excess for h → Zγ |
| title_full | The SM expected branching ratio for h → γγ and an excess for h → Zγ |
| title_fullStr | The SM expected branching ratio for h → γγ and an excess for h → Zγ |
| title_full_unstemmed | The SM expected branching ratio for h → γγ and an excess for h → Zγ |
| title_short | The SM expected branching ratio for h → γγ and an excess for h → Zγ |
| title_sort | sm expected branching ratio for h γγ and an excess for h zγ |
| topic | Higgs Properties Specific BSM Phenomenology |
| url | https://doi.org/10.1007/JHEP10(2024)135 |
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