Novel $|V_{cb}|$ extraction method via boosted $bc$-tagging with in-situ calibration
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arXiv
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| Autores principales: | , , , , , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| _version_ | 1866908298218831872 |
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| author | Zhao, Yuzhe Li, Congqiao Agapitos, Antonios Fu, Dawei Gao, Leyun Mao, Yajun Li, Qiang |
| author_facet | Zhao, Yuzhe Li, Congqiao Agapitos, Antonios Fu, Dawei Gao, Leyun Mao, Yajun Li, Qiang |
| contents | We present a novel method for measuring $|V_{cb}|$ at the LHC using an advanced boosted-jet tagger to identify "$bc$ signatures". By associating boosted $W \rightarrow bc$ signals with $bc$-matched jets from top-quark decays, we enable an in-situ calibration of the tagger. This approach significantly suppresses backgrounds while reducing uncertainties in flavor tagging efficiencies -- key to improving measurement precision. Our study is enabled by the development of realistic, AI-based large- and small-radius taggers, Sophon and the newly introduced SophonAK4, validated to match ATLAS and CMS's state-of-the-art taggers. The method complements the conventional small radius jet approach and enables a ~30% improvement in $|V_{cb}|$ precision under HL-LHC projections. As a byproduct, it enhances $H^{\pm} \rightarrow bc$ search sensitivity by a factor of 2--5 over the recent ATLAS result based on Run 2 data. Our work offers a new perspective for the precision $|V_{cb}|$ measurement and highlights the potential of using advanced tagging models to probe unexplored boosted regimes at the LHC. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2503_00118 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Novel $|V_{cb}|$ extraction method via boosted $bc$-tagging with in-situ calibration Zhao, Yuzhe Li, Congqiao Agapitos, Antonios Fu, Dawei Gao, Leyun Mao, Yajun Li, Qiang High Energy Physics - Phenomenology We present a novel method for measuring $|V_{cb}|$ at the LHC using an advanced boosted-jet tagger to identify "$bc$ signatures". By associating boosted $W \rightarrow bc$ signals with $bc$-matched jets from top-quark decays, we enable an in-situ calibration of the tagger. This approach significantly suppresses backgrounds while reducing uncertainties in flavor tagging efficiencies -- key to improving measurement precision. Our study is enabled by the development of realistic, AI-based large- and small-radius taggers, Sophon and the newly introduced SophonAK4, validated to match ATLAS and CMS's state-of-the-art taggers. The method complements the conventional small radius jet approach and enables a ~30% improvement in $|V_{cb}|$ precision under HL-LHC projections. As a byproduct, it enhances $H^{\pm} \rightarrow bc$ search sensitivity by a factor of 2--5 over the recent ATLAS result based on Run 2 data. Our work offers a new perspective for the precision $|V_{cb}|$ measurement and highlights the potential of using advanced tagging models to probe unexplored boosted regimes at the LHC. |
| title | Novel $|V_{cb}|$ extraction method via boosted $bc$-tagging with in-situ calibration |
| topic | High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2503.00118 |