English

Constraints on new physics from decays of polarized $\Lambda_b^0$ baryons at the FCC-ee

High Energy Physics - Experiment 2026-03-06 v2

Abstract

The Z0Z^0 bosons produced in electron-positron collisions at the potential Future Circular Collider (FCC-ee) provide unique opportunities for flavour physics. The non-zero polarization of \Lb baryons produced in Z0Z^0 decays enables access to a much larger set of observables than at the LHC, where the Λb0\Lambda_b^0 baryons are produced unpolarized. This paper presents a toy angular analysis of Λb0Λ(pπ)μ+μ\Lambda_b^0\to \Lambda(\to p\pi^-)\mu^+\mu^- decays using simulation samples of collisions at the FCC-ee reconstructed using the IDEA detector concept and assuming a dataset of 6×10126\times 10^{12} Z0Z^0 bosons. While the statistical sensitivity achieved for individual angular observables is not expected to significantly exceed that from the LHCb Upgrade II experiment, the addition of the polarized observables leads to a significant improvement of the knowledge on the Wilson coefficients C9()C_{9^{(\prime)}} and C10()C_{10^{(\prime)}}.

Keywords

Cite

@article{arxiv.2510.02225,
  title  = {Constraints on new physics from decays of polarized $\Lambda_b^0$ baryons at the FCC-ee},
  author = {Anja Beck and Mero Elmarassy and Asher Sabbagh and Michal Kreps and Eluned Smith},
  journal= {arXiv preprint arXiv:2510.02225},
  year   = {2026}
}