Precise measurement of CP violating τ EDM through e + e − → γ *, ψ(2s) → τ + τ −
Abstract A nonzero electric dipole moment of a tauon, d τ , signals CP violation and provides an important probe for new physics. We study methods to measure d τ at low energy e + e − colliders through the processes e + e − → γ *, ψ(2S) → τ + τ − with τ ± decays into a charged hadron and a tau neutr...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2025-04-01
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| Series: | Journal of High Energy Physics |
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| Online Access: | https://doi.org/10.1007/JHEP04(2025)001 |
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| author | Xiao-Gang He Chia-Wei Liu Jian-Ping Ma Chang Yang Zi-Yue Zou |
| author_facet | Xiao-Gang He Chia-Wei Liu Jian-Ping Ma Chang Yang Zi-Yue Zou |
| author_sort | Xiao-Gang He |
| collection | DOAJ |
| description | Abstract A nonzero electric dipole moment of a tauon, d τ , signals CP violation and provides an important probe for new physics. We study methods to measure d τ at low energy e + e − colliders through the processes e + e − → γ *, ψ(2S) → τ + τ − with τ ± decays into a charged hadron and a tau neutrino. We point out that, with measuring energies of the charged hadron, Im(d τ ) can be measured. On the other hand, selecting events of τ decays after traveling more than the detector resolution distance, Re(d τ ) can also be determined. We find that the precision at Super Tau-Charm Facility (STCF) running at the center energy of m ψ(2S) for 10 year data accumulation, the precision of Im(d τ ) and Re(d τ ) are found to be 1.8 and 11 in unit of 10−18 e cm, respectively. The sensitivity for d τ measurement precision at the STCF can be reached its optimum at a central energy of 6.3 GeV, achieving a precision of 0.7 for Im(d τ ) and 2.8 for Re(d τ ) in unit of 10 −18 e cm. |
| format | Article |
| id | doaj-art-95aabd2299114cb1b230876dc9e8fb8f |
| institution | OA Journals |
| issn | 1029-8479 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj-art-95aabd2299114cb1b230876dc9e8fb8f2025-08-20T02:15:06ZengSpringerOpenJournal of High Energy Physics1029-84792025-04-012025411010.1007/JHEP04(2025)001Precise measurement of CP violating τ EDM through e + e − → γ *, ψ(2s) → τ + τ −Xiao-Gang He0Chia-Wei Liu1Jian-Ping Ma2Chang Yang3Zi-Yue Zou4State Key Laboratory of Dark Matter Physics, Tsung-Dao Lee Institute and School of Physics and Astronomy, Shanghai Jiao Tong UniversityState Key Laboratory of Dark Matter Physics, Tsung-Dao Lee Institute and School of Physics and Astronomy, Shanghai Jiao Tong UniversitySchool of Physics, Henan Normal UniversityState Key Laboratory of Dark Matter Physics, Tsung-Dao Lee Institute and School of Physics and Astronomy, Shanghai Jiao Tong UniversityState Key Laboratory of Dark Matter Physics, Tsung-Dao Lee Institute and School of Physics and Astronomy, Shanghai Jiao Tong UniversityAbstract A nonzero electric dipole moment of a tauon, d τ , signals CP violation and provides an important probe for new physics. We study methods to measure d τ at low energy e + e − colliders through the processes e + e − → γ *, ψ(2S) → τ + τ − with τ ± decays into a charged hadron and a tau neutrino. We point out that, with measuring energies of the charged hadron, Im(d τ ) can be measured. On the other hand, selecting events of τ decays after traveling more than the detector resolution distance, Re(d τ ) can also be determined. We find that the precision at Super Tau-Charm Facility (STCF) running at the center energy of m ψ(2S) for 10 year data accumulation, the precision of Im(d τ ) and Re(d τ ) are found to be 1.8 and 11 in unit of 10−18 e cm, respectively. The sensitivity for d τ measurement precision at the STCF can be reached its optimum at a central energy of 6.3 GeV, achieving a precision of 0.7 for Im(d τ ) and 2.8 for Re(d τ ) in unit of 10 −18 e cm.https://doi.org/10.1007/JHEP04(2025)001CP ViolationElectric Dipole Moments |
| spellingShingle | Xiao-Gang He Chia-Wei Liu Jian-Ping Ma Chang Yang Zi-Yue Zou Precise measurement of CP violating τ EDM through e + e − → γ *, ψ(2s) → τ + τ − Journal of High Energy Physics CP Violation Electric Dipole Moments |
| title | Precise measurement of CP violating τ EDM through e + e − → γ *, ψ(2s) → τ + τ − |
| title_full | Precise measurement of CP violating τ EDM through e + e − → γ *, ψ(2s) → τ + τ − |
| title_fullStr | Precise measurement of CP violating τ EDM through e + e − → γ *, ψ(2s) → τ + τ − |
| title_full_unstemmed | Precise measurement of CP violating τ EDM through e + e − → γ *, ψ(2s) → τ + τ − |
| title_short | Precise measurement of CP violating τ EDM through e + e − → γ *, ψ(2s) → τ + τ − |
| title_sort | precise measurement of cp violating τ edm through e e γ ψ 2s τ τ |
| topic | CP Violation Electric Dipole Moments |
| url | https://doi.org/10.1007/JHEP04(2025)001 |
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