Full analysis of CP violation induced by the decay angular correlations in four-body cascade decays of heavy hadrons

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Main Authors: Zhang, Zhen-Hua, Yang, Jian-Yu, Guo, Xin-Heng
Format: Preprint
Published: 2025
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author Zhang, Zhen-Hua
Yang, Jian-Yu
Guo, Xin-Heng
author_facet Zhang, Zhen-Hua
Yang, Jian-Yu
Guo, Xin-Heng
contents The violation of the charge-parity (CP) transformation symmetry, which although has been observed in plenty of pure meson decay processes, was only confirmed just very recently by the LHCb collaboration in the four-body decay of the heavy baryon $Λ_b^0$, $Λ_b^0\to p K^- π^+ π^-$, through a comparison of the decay branching ratio with that of the CP-conjugate process. However, the detailed dynamics behind this CP asymmetry is obviously far from clear. In this paper, we propose a formalism for the full analysis of the decay angular correlations in four-body cascade decays of heavy hadrons which can provide more information about the CP violation in these decays. To illustrate this, we apply the decay angular correlation analysis of CP violation to another four-body decay channel that involve baryons, $B^0\to p\bar{p}K^+π^-$, which has also been investigated by the LHCb collaboration with no evidence of CP violation being found. Surprisingly, with the event yield extracted inversely from the published data of LHCb, we obtain non-zero CP asymmetries of about $10\%$ corresponding to the decay angular correlations at larger than $5σ$ confidence level, which are considerably larger than the CPA asymmetries observed in the $Λ_b^0\to p K^- π^+ π^-$ channel, indicating that CP violation could have been observed in processes involving baryons much earlier if the full analysis of angular correlations had been performed. We suggest our experimental colleagues to perform full decay angular correlation analyses of CP violation in four-body decays of heavy hadrons, including the above two decay channels.
format Preprint
id arxiv_https___arxiv_org_abs_2504_19228
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Full analysis of CP violation induced by the decay angular correlations in four-body cascade decays of heavy hadrons
Zhang, Zhen-Hua
Yang, Jian-Yu
Guo, Xin-Heng
High Energy Physics - Phenomenology
High Energy Physics - Experiment
The violation of the charge-parity (CP) transformation symmetry, which although has been observed in plenty of pure meson decay processes, was only confirmed just very recently by the LHCb collaboration in the four-body decay of the heavy baryon $Λ_b^0$, $Λ_b^0\to p K^- π^+ π^-$, through a comparison of the decay branching ratio with that of the CP-conjugate process. However, the detailed dynamics behind this CP asymmetry is obviously far from clear. In this paper, we propose a formalism for the full analysis of the decay angular correlations in four-body cascade decays of heavy hadrons which can provide more information about the CP violation in these decays. To illustrate this, we apply the decay angular correlation analysis of CP violation to another four-body decay channel that involve baryons, $B^0\to p\bar{p}K^+π^-$, which has also been investigated by the LHCb collaboration with no evidence of CP violation being found. Surprisingly, with the event yield extracted inversely from the published data of LHCb, we obtain non-zero CP asymmetries of about $10\%$ corresponding to the decay angular correlations at larger than $5σ$ confidence level, which are considerably larger than the CPA asymmetries observed in the $Λ_b^0\to p K^- π^+ π^-$ channel, indicating that CP violation could have been observed in processes involving baryons much earlier if the full analysis of angular correlations had been performed. We suggest our experimental colleagues to perform full decay angular correlation analyses of CP violation in four-body decays of heavy hadrons, including the above two decay channels.
title Full analysis of CP violation induced by the decay angular correlations in four-body cascade decays of heavy hadrons
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
url https://arxiv.org/abs/2504.19228