Prospects for $P$ and $C\!P$ violation in $\Lambda_{c}^{+}$ decays with polarized beam at Super Tau-Charm Facility

TL;DR

This paper assesses how the Super Tau-Charm Facility can improve the detection of parity and CP violations in Lambda_c+ decays using polarized beams, offering insights into physics beyond the Standard Model.

Contribution

It evaluates the potential precision and sensitivity of measuring P and CP violation parameters in Lambda_c+ decays at STCF with polarized beams, highlighting the benefits of beam polarization.

Findings

Longitudinal beam polarization enhances sensitivity to P and CP violation.

Expected precisions of P-violating parameters are significantly improved with polarization.

The study provides benchmarks for future experimental searches at STCF.

Abstract

Weak decays of the charmed baryons offer an ideal platform to study parity ($P$) and charge conjugation-parity ($C\!P$) violation in quark sector, to stringently test the Standard Model and search for new physics. It is a key goal in the next-generation positron-electron collider, such as the Super Tau-Charm Facility (STCF). Thanks to the quantum-entangled pair production with super high luminosity and the possibility of beam polarization, STCF provides a unique environment to probe such symmetry violations with unprecedented sensitivity. In this paper, we evaluate the precisions of the $P$-violating parameters and subsequently obtain the expected sensitivity of the $C\!P$-violating parameters in charmed baryon decays of $\Lambda_{c}^{+}\to p\pi^0$, $p\eta$, $\Lambda K^+$, $\Sigma^0 K^+$, and $\Sigma^+ K^0_S$, regarding to different polarization setups in STCF. The study suggests that the implementation of longitudinal beam polarization in STCF would greatly enhance the experimental capability in studying $P$ and $C\!P$ violation.