Nonfactorizable charming-loop contribution to FCNC $B_s\to γl^+l^-$ decay
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arXiv
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| Hauptverfasser: | , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866909204121387008 |
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| author | Belov, Ilia Berezhnoy, Alexander Melikhov, Dmitri |
| author_facet | Belov, Ilia Berezhnoy, Alexander Melikhov, Dmitri |
| contents | We present the first theoretical calculation of nonfactorizable charm-quark loop contributions to the $B_s\to γl^+l^-$ amplitude. We calculate the relevant form factors, $H_{A,V}^{\rm NF}(k'^2,k^2)$, and provide convenient parametrizations of our results in the form of fit functions of two variables, $k'^2$ and $k^2$, applicable in the region below hadron resonances, $k'^2 < M_{J/ψ}^2$ and $k^2 < M_ϕ^2$. We report that factorizable and nonfactorizable charm contributions to the $B_s\toγl^+l^-$ amplitude have opposite signs. To compare the charm and the top contributions, it is convenient to express the NF charming loop contribution as a non-universal (i.e., dependent on the reaction) $q^2$-dependent correction $Δ^{\rm NF}C_7(q^2)$ to the Wilson coefficient $C_7$. For the $B_s\toγl^+l^-$ amplitude, the correction is found to be positive, $Δ^{\rm NF} C_7(q^2)/C_7 > 0$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2404_01222 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Nonfactorizable charming-loop contribution to FCNC $B_s\to γl^+l^-$ decay Belov, Ilia Berezhnoy, Alexander Melikhov, Dmitri High Energy Physics - Phenomenology We present the first theoretical calculation of nonfactorizable charm-quark loop contributions to the $B_s\to γl^+l^-$ amplitude. We calculate the relevant form factors, $H_{A,V}^{\rm NF}(k'^2,k^2)$, and provide convenient parametrizations of our results in the form of fit functions of two variables, $k'^2$ and $k^2$, applicable in the region below hadron resonances, $k'^2 < M_{J/ψ}^2$ and $k^2 < M_ϕ^2$. We report that factorizable and nonfactorizable charm contributions to the $B_s\toγl^+l^-$ amplitude have opposite signs. To compare the charm and the top contributions, it is convenient to express the NF charming loop contribution as a non-universal (i.e., dependent on the reaction) $q^2$-dependent correction $Δ^{\rm NF}C_7(q^2)$ to the Wilson coefficient $C_7$. For the $B_s\toγl^+l^-$ amplitude, the correction is found to be positive, $Δ^{\rm NF} C_7(q^2)/C_7 > 0$. |
| title | Nonfactorizable charming-loop contribution to FCNC $B_s\to γl^+l^-$ decay |
| topic | High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2404.01222 |