Testing of P and CP symmetries with e+e- → J/ψ Λ(Λ)over-bar

We propose to test P- and CP-symmetries with the process e(+)e(-) -> J/psi Lambda(Lambda) over bar. The general form of the angular distribution of the process is derived and several observables for the proposed test are introduced. With these observables one can distinguish the effects of P-violations in the production of J/psi from its decay into a pair of Lambda(Lambda) over bar . Numerical estimations for proposed asymmetries of P-violation due to Zexchange in SM are given. Our results show that BESIII has reached the sensitivity to probe these effects. At the proposed super-tau-charm factory with much enhanced luminosity it will be able to test the SM predictions with high precision. CPviolating effect in J/psi Lambda(Lambda) over bar can also be tested. In particular, BESIII data already reached the sensitivity to prove CPviolating effect due to current upper limit of electric dipole moment of Lambda. At the proposed super-tau-charm factory the upper limit can be improved by an order of magnitude. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.

Automated summary

We propose a test of P- and CP-symmetries using the process e(+)e(-) -> J/psi Lambda(Lambda) over bar. The angular distribution of the process is derived and several observables are introduced for the proposed test. Numerical estimations for P-violating asymmetries in the production and decay of J/psi are given. Results show that BESIII has reached the sensitivity to probe these effects and the proposed super-tau-charm factory can further improve the precision of the tests.