Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2512.19085 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866917356008112128 |
|---|---|
| author | Zhao, Chun-Qiu Cao, Xu Dai, Jian-Ping |
| author_facet | Zhao, Chun-Qiu Cao, Xu Dai, Jian-Ping |
| contents | In the center-of-mass frame, the spin density matrix for octet baryon-antibaryon pairs produced in polarized electron-positron annihilation is unambiguously determined within the one-photon-exchange approximation. The formalism simultaneously incorporates parity ($P$) and combined parity-charge conjugation ($CP$) violation arising from the coupling of the intermediate virtual photon to the baryon pair. The finite electron mass is explicitly accounted for as a correction to these $P$ and $CP$ violating effects. Built on the spin projection operator, the derived full and compact spin density matrix provides a natural starting point for evaluating other quantities of physical interest -- particularly angular distributions of sequential decays and the quantum entanglement of hyperon pairs. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_19085 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Spin density matrix of baryon-antibaryon pairs in electron-positron annihilation with $P$ and $CP$ violation including electron mass Zhao, Chun-Qiu Cao, Xu Dai, Jian-Ping High Energy Physics - Phenomenology In the center-of-mass frame, the spin density matrix for octet baryon-antibaryon pairs produced in polarized electron-positron annihilation is unambiguously determined within the one-photon-exchange approximation. The formalism simultaneously incorporates parity ($P$) and combined parity-charge conjugation ($CP$) violation arising from the coupling of the intermediate virtual photon to the baryon pair. The finite electron mass is explicitly accounted for as a correction to these $P$ and $CP$ violating effects. Built on the spin projection operator, the derived full and compact spin density matrix provides a natural starting point for evaluating other quantities of physical interest -- particularly angular distributions of sequential decays and the quantum entanglement of hyperon pairs. |
| title | Spin density matrix of baryon-antibaryon pairs in electron-positron annihilation with $P$ and $CP$ violation including electron mass |
| topic | High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2512.19085 |