Physicists narrow search for mysterious particles that could rewrite particle physics
Researchers at CERN's LHCb experiment found no evidence of heavy neutral leptons in billions of B-meson collisions, but the null result is significant: it tightens constraints on where these hypothetical particles could hide. The findings matter because detecting such particles could reveal new physics beyond the Standard Model and reshape our understanding of fundamental forces.
Originaltitel: Search for heavy neutral leptons in B-meson decays
<p>A search for long-lived heavy neutral leptons produced in B-meson decays and decaying to a μ<sup>±</sup>π<sup>-/+</sup> final state is performed with data collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of 13TeV, corresponding to an integrated luminosity of 5 fb<sup>-1</sup>. The results are interpreted in both lepton-number-conserving and lepton-number-violating scenarios. No significant excess is observed. Constraints are placed on the squared mixing element |U<sub>μN</sub>|<sup>2</sup> to the active muon neutrino, under the assumption that couplings to other lepton flavours are negligible, in the mass range of 1.6-5.5 GeV.</p>