Fundamental Tests of P and CP Symmetries Using Octet Baryons at the $J/ψ$ Threshold
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2024
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| _version_ | 1866917822782767104 |
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| author | Du, Yong He, Xiao-Gang Ma, Jian-Ping Du, Xin-Yu |
| author_facet | Du, Yong He, Xiao-Gang Ma, Jian-Ping Du, Xin-Yu |
| contents | We systematically investigate tests of the parity P and the combined parity and charge-conjugate CP symmetries from differential angular distributions of $J/ψ$ decaying into the lowest-lying baryon pairs at BESIII and the next-generation super tau-charm facilities (STCFs). Large corrections from $Z$ and $W$ exchange induced parity violating effects are found for $J/ψ$ decays with large logarithms resummed up to $\mathcal{O}(α_s)$. The parity-violating asymmetries on the production and the decay sides of $J/ψ$ are both estimated to be of $\mathcal{O}(10^{-4})$, thus barely observable with the 10 billion $J/ψ$ events currently collected at BESIII. Nevertheless, these asymmetries utilizing the current BESIII data already permit a measurement of the weak mixing angle with an absolute uncertainty $δs_w^2\approx{0.09}$, corresponding to the first determination of $s_w^2$ at the $J/ψ$ threshold. In the future, STCFs are estimated to improve this bound by a factor of $\sim\,20$ to $δs_w^2\approx{0.005}$ within one year based on luminosity rescaling. We also obtain the 95% confidence level upper bounds on the electric dipole moments of the octet baryons, which are of $\mathcal{O}(10^{-18})\,e{\rm\,cm}$ for BESIII and $\mathcal{O}(10^{-19})\,e{\rm\,cm}$ for STCFs. These bounds are improved by two to three orders of magnitude in comparison with the only existing one on $Λ$ from Fermilab. The method discussed in this work also paves a way for a first and direct measurement of the $Ξ$ and $Σ$ electric dipole moments. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2405_09625 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Fundamental Tests of P and CP Symmetries Using Octet Baryons at the $J/ψ$ Threshold Du, Yong He, Xiao-Gang Ma, Jian-Ping Du, Xin-Yu High Energy Physics - Phenomenology High Energy Physics - Experiment We systematically investigate tests of the parity P and the combined parity and charge-conjugate CP symmetries from differential angular distributions of $J/ψ$ decaying into the lowest-lying baryon pairs at BESIII and the next-generation super tau-charm facilities (STCFs). Large corrections from $Z$ and $W$ exchange induced parity violating effects are found for $J/ψ$ decays with large logarithms resummed up to $\mathcal{O}(α_s)$. The parity-violating asymmetries on the production and the decay sides of $J/ψ$ are both estimated to be of $\mathcal{O}(10^{-4})$, thus barely observable with the 10 billion $J/ψ$ events currently collected at BESIII. Nevertheless, these asymmetries utilizing the current BESIII data already permit a measurement of the weak mixing angle with an absolute uncertainty $δs_w^2\approx{0.09}$, corresponding to the first determination of $s_w^2$ at the $J/ψ$ threshold. In the future, STCFs are estimated to improve this bound by a factor of $\sim\,20$ to $δs_w^2\approx{0.005}$ within one year based on luminosity rescaling. We also obtain the 95% confidence level upper bounds on the electric dipole moments of the octet baryons, which are of $\mathcal{O}(10^{-18})\,e{\rm\,cm}$ for BESIII and $\mathcal{O}(10^{-19})\,e{\rm\,cm}$ for STCFs. These bounds are improved by two to three orders of magnitude in comparison with the only existing one on $Λ$ from Fermilab. The method discussed in this work also paves a way for a first and direct measurement of the $Ξ$ and $Σ$ electric dipole moments. |
| title | Fundamental Tests of P and CP Symmetries Using Octet Baryons at the $J/ψ$ Threshold |
| topic | High Energy Physics - Phenomenology High Energy Physics - Experiment |
| url | https://arxiv.org/abs/2405.09625 |