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| Main Authors: | , , , |
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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2506.11196 |
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| _version_ | 1866915466394468352 |
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| author | Dorigo, Mirco Raiz, Sebastiano Tonelli, Diego Zlebcik, Radek |
| author_facet | Dorigo, Mirco Raiz, Sebastiano Tonelli, Diego Zlebcik, Radek |
| contents | We present a method to measure time-dependent $CP$ violation in $B^0$ decays produced in $Υ(4S) \to B^0\overline{B}^0$ events at $B$ factories without reconstructing the signal decay vertex. The method exploits the sensitivity of the tag $\overline{B}^0$ decay time to $CP$ violation in the $B^0$ signal. It relies on a compact $e^+e^-$ interaction region and excellent vertex resolution, which enable precise measurement of the displacement between production and decay vertices of the tag meson. We study an application to $B^0\toπ^0π^0$ decays using a simplified simulation that approximates the conditions of the Belle II experiment at the SuperKEKB collider. Our approach achieves a sensitivity on mixing-induced $CP$ violation that would require 20 times larger samples with standard approaches. When incorporated into the $B \to ππ$ isospin analysis, the expected results would reduce the degeneracy of $ϕ_2$ solutions and significantly increase precision. This work opens a path to previously inaccessible $CP$-violation studies enhancing and accelerating the reach of Belle II and future flavor physics programs. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2506_11196 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Unlocking time-dependent $CP$ violation without signal vertexing at $B$ factories Dorigo, Mirco Raiz, Sebastiano Tonelli, Diego Zlebcik, Radek High Energy Physics - Phenomenology High Energy Physics - Experiment We present a method to measure time-dependent $CP$ violation in $B^0$ decays produced in $Υ(4S) \to B^0\overline{B}^0$ events at $B$ factories without reconstructing the signal decay vertex. The method exploits the sensitivity of the tag $\overline{B}^0$ decay time to $CP$ violation in the $B^0$ signal. It relies on a compact $e^+e^-$ interaction region and excellent vertex resolution, which enable precise measurement of the displacement between production and decay vertices of the tag meson. We study an application to $B^0\toπ^0π^0$ decays using a simplified simulation that approximates the conditions of the Belle II experiment at the SuperKEKB collider. Our approach achieves a sensitivity on mixing-induced $CP$ violation that would require 20 times larger samples with standard approaches. When incorporated into the $B \to ππ$ isospin analysis, the expected results would reduce the degeneracy of $ϕ_2$ solutions and significantly increase precision. This work opens a path to previously inaccessible $CP$-violation studies enhancing and accelerating the reach of Belle II and future flavor physics programs. |
| title | Unlocking time-dependent $CP$ violation without signal vertexing at $B$ factories |
| topic | High Energy Physics - Phenomenology High Energy Physics - Experiment |
| url | https://arxiv.org/abs/2506.11196 |