2022/07/19 by BABAR Collaboration · 5 citations
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex)
paper · doi:10.48550/arxiv.2207.09575
This article presents a model independent search for an additional, mostly sterile, Heavy Neutral Lepton (HNL), that is capable of mixing with the Standard Model τ neutrino with a mixing strength of |Uτ4|2, corresponding to the absolute square of the extended Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix element. Data from the \babar~ experiment, with a total integrated luminosity of 424~ fb-1, are analyzed using a kinematic approach that makes no assumptions on the model behind the origins of the HNL, its lifetime or decay modes. No significant signal is found. Upper limits on |Uτ4|2 at the 95% confidence level, depend on the HNL mass hypothesis and vary from 2.31 × 10-2 to 5.04 × 10-6 (with all uncertainties considered), across the mass range 100 < m4 < 1300 ~MeV/c2; the more stringent limits being placed at higher masses.