Science2021globalhigh confidence

A result published in March 2021 by the LHCb experiment, combining data collected between 2010-2016 and 2017-2018, found only a 1 in 1,000 chance that an observed difference between B meson decays into two muons versus an electron-positron pair was due to random statistical fluctuation.

Notes on verification

Confirmed by CERN press release, LHCb arXiv paper, and multiple independent physics news outlets consistently reporting 3.1 sigma significance (~1 in 1000 p-value).

Sources