Search for heavy neutral lepton production in $K^{+}$ decays to positrons

Abstract

A search for heavy neutral lepton ($N$) production in $K^{+}\to e^{+}N$ decays using the data sample collected by the NA62 experiment at CERN in 2017--2018 is reported. Upper limits of the extended neutrino mixing matrix element $|U_{e4}{|}^2$ are established at the level of $10^{-9}$ over most of the accessible heavy neutral lepton mass range 144--462 MeV/$c^2$, with the assumption that the lifetime exceeds 50 ns. These limits improve significantly upon those of previous production and decay searches. The $|U_{e4}{|}^2$ range favoured by Big Bang Nucleosynthesis is excluded up to a mass of about 340 MeV/$c^2$.

Version accepted for publication in Physics Letters B (28 June 2020)

References in corpus (2)

• Constraints on Sterile Neutrinos in the MeV to GeV Mass Range
• Search for heavy neutral lepton production in $K^{+}$ decays

Cited by in corpus (23)

• The Present and Future Status of Heavy Neutral Leptons
• The Search for Feebly-Interacting Particles
• Search for $K^{+}$ decays to a muon and invisible particles
• Heavy neutral leptons below the kaon mass at hodoscopic detectors
• Testing Lepton Flavor Universality with Pion, Kaon, Tau, and Beta Decays
• The MicroBooNE Experiment, the NuMI Absorber, and Heavy Neutral Leptons
• New constraints on tau-coupled Heavy Neutral Leptons with masses $m_N=280-970$ MeV
• Probing HNL-ALP couplings at colliders
• Search for heavy Majorana neutrinos at electron-proton colliders
• Neutrinoless double beta decay in the minimal type-I seesaw model: How the enhancement or cancellation happens?
• Low-Energy Supernovae Bounds on Sterile Neutrinos
• Revisiting PS191 limits on sterile neutrinos
• Modelling Heavy Neutral Leptons in Accelerator Beamlines
• Impostor Among $\nu$s: Dark Radiation Masquerading as Self-Interacting Neutrinos
• ALPs and HNLs at LHC and Muon Colliders: Uncovering New Couplings and Signals
• Workshop summary -- Kaons@CERN 2023
• Probe the Mixing Parameter $|V_{\tau N}{|}^2$ for Heavy Neutrinos
• Right handed neutrino production from $Z^{\prime }$ interactions in forward search experiments
• Enhancing the Sensitivity to Seesaw Predictions in Gauged $B-L$ Scenarios
• New Physics Searches at Kaon and Hyperon Factories
• Semi-Visible Dark Photon Phenomenology at the GeV Scale
• Heavy Neutral Lepton searches at an ICARUS-like detector using NuMI beam
• Characterizing Heavy Neutral Fermions via their Decays