Related papers: Background Suppression for $\mu\to e\gamma$ with P…
We study the lepton-flavor-violating reaction $\mu^+ e^- \to e^+ e^-$ within two extensions of the standard model that include heavy neutrinos. The reaction is studied in the low energy limit in the form of muonium decay $M\to e^+ e^-$ and…
The search for the Lepton Flavor Violating decay $\mu \to e \gamma$ exploits the most intense continuous muon beams, which can currently deliver $\sim 10^8$ muons per second. In the next decade, accelerator upgrades are expected in various…
This note presents an analysis of lepton-flavour-violating muon decays within the framework of a low-energy effective field theory that contains higher-dimensional operators allowed by QED and QCD symmetries. The decay modes $\mu\to e…
The radiative decay of the massive neutrino $\nu_i \rightarrow \nu_j \gamma$ in a circularly polarized electromagnetic wave is investigated within the Standard theory with lepton mixing. The decay probability in the wave field does not…
Lepton-flavor-violating decays of light pseudoscalars, $P=\pi^0,\eta,\eta'\to\mu e$, are stringently suppressed in the Standard Model up to tiny contributions from neutrino oscillations, so that their observation would be a clear indication…
The decay $\mu^-\to e^- \bar{\nu}_e\nu_\mu$ of a muon that is bound to a nucleus poses an unavoidable background for experiments such as Mu2e, COMET, and DeeMe searching for lepton-flavor-violating $\mu^-\to e^-$ conversion and thus…
The photon-neutrino processes $\gamma e^{\pm} \to e^{\pm} \nu \bar \nu$, $\gamma \to \nu \bar \nu$ and $\gamma \gamma \to \nu \bar \nu$ are investigated in the presence of a strongly magnetized and dense electron-positron plasma. The…
The Mu3e experiment aims to search for the lepton-flavour violating decay $\mu^+\rightarrow\ \text{e}^+ \text{e}^+ \text{e}^-$ with a sensitivity to one signal decay in $10^{16}$ muon decays at a muon stopping rate of $2\times 10^9…
We examine the muonium ($\mu ^+e^-$)-antimuonium ($\mu ^-e^+$) system in the models which accomodate the dilepton gauge bosons, and study their contributions to the ground state hyperfine splitting in ``muonium''. We also consider the…
We calculated the differential cross sections of the processes in which one of the pair created tau particles at an e^+ e^- collider decays into lepton flavor violating final states e.g. tau -> mu gamma, tau -> 3 mu, tau -> mu ee. Using the…
The decays $\mu \rightarrow e \gamma$, $\mu \rightarrow e \gamma \gamma$, and $\mu \rightarrow e e \bar e$ are analysed in the framework of the Pati-Salam type quark-lepton symmetry $SU(4)_V \otimes SU(2)_L \otimes G_R$ where the effects of…
Axion-like particles (ALPs) with lepton-flavor violating couplings can be probed in exotic muon and tau decays. The sensitivity of different experiments depends strongly on the ALP mass and its couplings to leptons and photons. For ALPs…
We speculate about the possible interpretations of the recently observed excess in the $h \to \tau \mu$ decay. We derive a robust lower bound on the Higgs boson coupling strength to a tau and a muon, even in presence of the most general new…
Charged lepton flavour violating transitions would be a clear signal of new physics beyond the Standard Model. Their search has been carried out in a variety of channels, the most sensitive being those involving a muon: however no positive…
The fundamental description of nature, beyond the Standard Model (SM), may include heavy neutrinos that mix and thus allow processes in which lepton flavor is not preserved. We investigate the impact of charged currents that couple heavy…
We propose a dark matter direct-detection strategy using charged particle decays at accelerator-based experiments. If ultralight $(m_\phi \ll \text{eV})$ dark matter has a misalignment abundance, its local field oscillates in time at a…
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 $7.5\times 10^{14}$…
Calculations of transverse polarization of leptons in the decay $W\rightarrow l\nu$ with polarized $W$'s are presented. Planned accelerators will produce enough $W$'s for observation of the Standard Model contributions to this polarization.…
We re-examine the possibility to measure the photon polarization in $B \to K^*\gamma$ decays, via decays in which the photon subsequently undergoes nuclear conversion to a lepton pair. We obtain compact expressions for the full…
This article reviews the current theoretical and experimental status of the field of muon decay and its potential to search for new physics beyond the Standard Model. The importance of rare muon processes with lepton flavor violation is…