Report
Precise measurement of CP violating $\tau$ EDM through $e^+ e^- \to \gamma^*, \psi(2s) \to \tau^+ \tau^-$
| العنوان: | Precise measurement of CP violating $\tau$ EDM through $e^+ e^- \to \gamma^*, \psi(2s) \to \tau^+ \tau^-$ |
|---|---|
| المؤلفون: | He, Xiao-Gang, Liu, Chia-Wei, Ma, Jian-Ping, Yang, Chang, Zou, Zi-Yue |
| سنة النشر: | 2025 |
| المجموعة: | High Energy Physics - Experiment High Energy Physics - Phenomenology |
| مصطلحات موضوعية: | High Energy Physics - Phenomenology, High Energy Physics - Experiment |
| الوصف: | A nonzero electric dipole moment of a tauon, $d_\tau$, signals CP violation and provides an important probe for new physics. We study methods to measure $d_\tau$ at low energy $e^+ e^-$ colliders through the processes $e^+e^- \to \gamma^*, \psi(2S) \to \tau^+\tau^-$ with $\tau^\pm$ decays into a charged hadron and a tau neutrino. We point out that, with measuring energies of the charged hadron, Im$(d_\tau)$ can be measured. On the other hand, selecting events of $\tau$ decays after traveling more than the detector resolution distance, Re$(d_\tau)$ can also be determined. We find that the precision at Super Tau-Charm Facility (STCF) running at the center energy of $m_{\psi (2S)}$ for 10 year data accumulation, the precision of Im$(d_\tau)$ and Re$(d_\tau)$ are found to be 3.5 and 11 in unit of $10^{-18}~e\,\text{cm}$, respectively. The sensitivity for $d_\tau$ measurement precision at the STCF can be reached its optimum at a central energy of $6.3~\text{GeV}$, achieving a precision of $1.3$ for Im$(d_\tau)$ and $2.9$ for Re$(d_\tau)$ in unit of $ 10^{-18}~e\,\text{cm}$. Comment: 4 pages, 2 figures |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/2501.06687 |
| رقم الانضمام: | edsarx.2501.06687 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |