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$Λ_{b} \to Λ^{(*)} ν \bar{ν}$ decays and the recent Belle II $B^{+} \to K^{+} ν \bar{ν}$ data

Diganta Das ¹, Dargi Shameer ¹, and Ria Sain^2,3

¹Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad 500 032, India
²Institute of Particle and Nuclear Physics, Henan Normal University, Xinxiang 453007, China
³Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOE), Central China Normal University, Wuhan, Hubei 430079, China

Phys. Rev. D 112, 013012 – Published 30 July, 2025

DOI: https://doi.org/10.1103/s3gv-pw5w

Abstract

The Belle II experiment has recently reported the first measurement of $B^{+} \to K^{+} ν \bar{ν}$ decay which exceeds the Standard Model prediction by approximately $2.7 σ$ . The deviation may indicate the presence of new physics beyond the Standard Model in the $b \to s ν \bar{ν}$ sector. Under this assumption, we study the hadronic $Λ_{b} \to Λ (\to p π) ν \bar{ν}$ and $Λ_{b} \to Λ^{*} (\to N \bar{K}) ν \bar{ν}$ decays within both the Standard Model and beyond. We work in a low-energy effective field theory framework with additional light right-handed neutrinos. We calculate the differential branching ratios of these decay modes and explore the implications of the Belle II results through various observables.

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References (33)

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Phys. Rev. D 112, 013012– Published 30 July, 2025

Vol. 112, Iss. 1 — 1 July 2025

Received 30 March 2025
Accepted 9 July 2025

DOI: https://doi.org/10.1103/s3gv-pw5w

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

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$Λ_{b} \to Λ^{(*)} ν \bar{ν}$ decays and the recent Belle II $B^{+} \to K^{+} ν \bar{ν}$ data

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Λb→Λ(*)νν¯ decays and the recent Belle II B+→K+νν¯ data

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$Λ_{b} \to Λ^{(*)} ν \bar{ν}$ decays and the recent Belle II $B^{+} \to K^{+} ν \bar{ν}$ data