Rare neutral B-meson decay anomaly
The LHCb experiment published a comprehensive analysis on July 18, 2026, detailing anomalies in the B0 → K*0μ+μ− decay that deviate from the Standard Model with a statistical significance of 3.9 sigma. As of July 18, 2026, these findings represent the strongest B0 meson anomaly to survive additional data screening, with the CMS experiment also observing consistent results. This anomaly, first reported by LHCb in July 2013 concerning the P5' anomaly in B→K*μ+μ– decays, continues to be an active area of research to determine if it signals new physics beyond the Standard Model.
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July 2026 — 2 developments
LHCb Experiment Reports 3.9 Sigma Anomaly in B-Meson Decay, Hinting at New Physics
The LHCb experiment has published a comprehensive analysis of the B0 → K*0μ+μ− decay, detailing anomalies that deviate from the Standard Model with a statistical significance of 3.9 sigma. These findings, which have been accepted and await publication, represent the strongest B0 meson anomaly to survive additional data screening. The CMS experiment has also observed results consistent with this anomaly, strengthening the possibility of new fundamental particles or forces beyond the Standard Model.
Rare B-Meson Decay Anomaly Remains Active Research Area in 2026
As of 2026, the rare neutral B-meson decay anomaly continues to be a prominent and active area of research in particle physics. Scientists are diligently working to refine theoretical calculations and gather more precise experimental data from various sources, including LHCb and Belle II. The primary objective is to definitively ascertain whether these observed deviations are merely statistical fluctuations or if they represent compelling evidence for the existence of new physics beyond the Standard Model.
July 2013 — 1 developments
LHCb Experiment Reports First Significant Deviation in B-Meson Decay Angular Distribution
The rare neutral B-meson decay anomaly first emerged in July 2013 with a significant deviation reported by the LHCb experiment. This initial finding concerned the angular distribution of B→K*μ+μ– decays, specifically known as the P5' anomaly. This unexpected result immediately captured considerable interest within the particle physics community, as it hinted at potential inconsistencies with the established Standard Model of particle physics.