Prospect for measurement of CP-violating observables in B s 0 → D s ∓ K ± $$ {B}_s^0\to {D}_s^{\mp }{K}^{\pm } $$ decays at a future Z factory

Abstract A precise determination of the CKM angle γ from B s 0 $$ {B}_s^0 $$ oscillations in B s 0 → D s ∓ K ± $$ {B}_s^0\to {D}_s^{\mp }{K}^{\pm } $$ decays offers a critical test of the Standard Model and probes for new physics. We present a comprehensive study on the prospects of measuring γ at a...

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Bibliographic Details
Main Authors: Ji Peng, Mingrui Zhao, Xiaolin Wang, Manqi Ruan, Hengne Li, Shanzhen Chen
Format: Article
Language:English
Published: SpringerOpen 2025-06-01
Series:Journal of High Energy Physics
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Online Access:https://doi.org/10.1007/JHEP06(2025)212
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Summary:Abstract A precise determination of the CKM angle γ from B s 0 $$ {B}_s^0 $$ oscillations in B s 0 → D s ∓ K ± $$ {B}_s^0\to {D}_s^{\mp }{K}^{\pm } $$ decays offers a critical test of the Standard Model and probes for new physics. We present a comprehensive study on the prospects of measuring γ at a future Tera-Z factory, utilizing the baseline detector concept of the Circular Electron Positron Collider (CEPC). A two-dimensional simultaneous fit framework, incorporating flavor tagging, decay time resolution modeling, and acceptance corrections, is developed using full Monte Carlo simulations of B s 0 → D s ∓ → K ∓ K ± π ∓ K ± $$ {B}_s^0\to {D}_s^{\mp}\left(\to {K}^{\mp }{K}^{\pm }{\pi}^{\mp}\right){K}^{\pm } $$ decays and inclusive background processes. The effective flavor tagging power reaches 23.6%, while the decay time resolution is determined to be 26 fs. Projecting to full statistics of signal events across three dominant D s − $$ {D}_s^{-} $$ decay channels, we estimate a statistical precision of σ(γ) = 0.69 ° , which corresponds to 4.1 Tera-Z boson equivalent data. This study has established the feasibility of sub-degree level γ measurements at a Z factory, highlighting its unique advantages in time-dependent CP violation studies through ultra-precise vertexing and background suppression capabilities.
ISSN:1029-8479