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arXiv · 2609.11840

Signatures of Invisible Fermions in $\Lambda_b^0 \to \Lambda_c^+ \ell^- \bar{X}_{\rm inv}$ Decays

Shantanu Sahoo·Soumitra Nandi
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Abstract

We investigate the effects of a massive invisible fermion in $\Lambda_b^0 \to \Lambda_c^+ \ell^- \bar{X}_{\rm inv}$ decays using a model-independent weak effective theory. Through a comprehensive angular analysis, we show that a nonzero invisible-particle mass leaves characteristic imprints on angular observables that can distinguish massless and massive invisible states. We further demonstrate that these observables provide strong discrimination among vector/axial-vector, scalar/pseudoscalar, and tensor interactions, as well as between left- and right-handed quark and lepton current operators.

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Shantanu Sahoo, Soumitra Nandi. 2026-09-10. Signatures of Invisible Fermions in $\Lambda_b^0 \to \Lambda_c^+ \ell^- \bar{X}_{\rm inv}$ Decays. https://arxiv.org/abs/2609.11840

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