Search for lepton flavour violating muon decay mediated by a new light particle in the MEG experiment

Abstract

We present the first direct search for lepton flavour violating muon decay mediated by a new light particle X, ${\mu }^{+}\to {\mathrm{e}}^{+}\mathrm{X},\mathrm{X}\to \gamma \gamma$. This search uses a dataset resulting from $7.5\times 10^{14}$ stopped muons collected by the MEG experiment at the Paul Scherrer Institut in the period 2009--2013. No significant excess is found in the mass region 20--45 MeV/c${}^2$ for lifetimes below 40 ps, and we set the most stringent branching ratio upper limits in the mass region of 20--40 MeV/c${}^2$, down to $\mathcal{O}(10^{-11})$ at 90\% confidence level.

References in corpus (37)

• Evidence for oscillation of atmospheric neutrinos
• A Unified Approach to the Classical Statistical Analysis of Small Signals
• Direct Evidence for Neutrino Flavor Transformation from Neutral-Current Interactions in the Sudbury Neutrino Observatory
• The SIMP Miracle
• Kernel Estimation in High-Energy Physics
• Trial factors for the look elsewhere effect in high energy physics
• The SIMPlest Miracle
• Signals For Supersymmetric Unification
• Probing MeV to 90 GeV axion-like particles with LEP and LHC
• The design of the MEG II experiment
• Revised constraints and Belle II sensitivity for visible and invisible axion-like particles
• Flaxion: a minimal extension to solve puzzles in the standard model
• ALPtraum: ALP production in proton beam dump experiments
• The Axiflavon
• Hunting for ALPs with Lepton Flavor Violation
• The MEG detector for $\mu +\to e+\gamma$ decay search
• Search for invisible decays of a Higgs boson using vector-boson fusion in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
• A search for two body muon decay signals
• Absorption of Scintillation Light in a 100 $\ell$ Liquid Xenon$\gamma$ Ray Detector and Expected Detector Performance
• Which group velocity of light in a dispersive medium?
• QED at NNLO with McMule
• A proposal of the gauge theory description of the small Schwarzschild black hole in AdS${}_5\times$S${}^5$
• Measurement of the Drell--Yan triple-differential cross section in $pp$ collisions at $\sqrt{s}=8$ TeV
• Electrophobic Scalar Boson and Muonic Puzzles
• Sensitivity of searches for new signals and its optimization
• Hunting the Flavon
• Lepton Flavor Violation with Displaced Vertices
• Phenomenology of flavon fields at the LHC
• A Family of WISPy Dark Matter Candidates
• The Hierarchion, a Relaxion Addressing the Standard Model's Hierarchies
• Measurement of the radiative decay of polarized muons in the MEG experiment
• Statistical Challenges for Searches for New Physics at the LHC
• Fully differential NLO predictions for the radiative decay of muons and taus
• Development and commissioning of the Timing Counter for the MEG Experiment
• Muon polarization in the MEG experiment: predictions and measurements
• The Architecture of MEG Simulation and Analysis Software
• Probing the Light Pseudoscalar Window

Cited by in corpus (13)

• Flavor probes of axion-like particles
• Looking forward to Lepton-flavor-violating ALPs
• The Search for Feebly-Interacting Particles
• QED at NNLO with McMule
• Science Case for the new High-Intensity Muon Beams HIMB at PSI
• Probing $\mu e\gamma \gamma$ contact interactions with $\mu \to e$ conversion
• Search for lepton-flavor-violating ALPs at a future muon collider and utilization of polarization-induced effects
• High-precision muon decay predictions for ALP searches
• Tree level Majorana neutrino mass from Type-1 $\times$ Type-2 Seesaw mechanism with Dark Matter
• Detailed analysis of chemical corrosion of ultra-thin wires used in drift chamber detectors
• Concurrent Exploration of Axion-Like Particle Interactions with Gauge Bosons at the LHC
• The measuring systems of the wire tension for the MEG II Drift Chamber by means of the resonant frequency technique
• Search for a Non-Relativistic Boson in Two-Body Antimuon Decay