Related papers: Background Suppression for $\mu\to e\gamma$ with P…
A new exclusion limit for the electromagnetic production of a light U(1) gauge boson {\gamma}' decaying to e^+e^- was determined by the A1 Collaboration at the Mainz Microtron. Such light gauge bosons appear in several extensions of the…
We entertain the idea that a suitable background of cold (very low momentum) pseudoscalar particles or condensate, may trigger a background that effectively generates Lorentz-invariance violation. This aether-like background induces a…
We show that the $\eta\gamma Z$ anomaly can be measured by analysing parity-violating effects in the $\eta-->\gamma\mu+\mu-$ decay. In this sense, we find that the longitudinal polarization of the outgoing $\mu^+$ is an appropriate…
In detection of electrons from $\mu \to e $ conversion process the monochromatic electron spectrum is transformed due to a photon emission and fluctuations of energy loss in a target. The selection criterion of $\mu \to e (\gamma)$…
MUonE is a proposed experiment designed to measure the hadronic vacuum polarization contribution to muon $g-2$ through elastic $\mu-e$ scattering. As such it employs an extremely high-resolution tracking apparatus. We point out that this…
The muon is playing a unique role in sub-atomic physics. Studies of muon decay both determine the overall strength and establish the chiral structure of weak interactions, as well as setting extraordinary limits on…
This paper explores the annihilation process of an electron-positron pair into a heavier lepton-antilepton pair, taking into account the presence of an external classical magnetic field. Additionally, it investigates corrections arising…
We analyze the $Z$-boson decay $Z\to \gamma\, X$ into a photon ($\gamma$) plus a hypothetical light boson ($X$) belonging to a dark or secluded sector. Due to its feeble interactions with Standard Model fields, this dark boson is behaving…
We assess the status of past and future experiments on lepton flavor violating (LFV) muon and tau decays into a light, invisible, axion-like particle (ALP), $a$. We propose a new experimental setup for MEG II, the MEGII-fwd, with a forward…
In this paper, we have investigated the elementary particle reaction ${e}^{+} {e}^{-} \rightarrow{\mu}^{+} {\mu}^{-}$ that results from the electron-positron interaction, at the leading order, with an intense laser wave of circular…
We calculate the rates and lepton (l) invariant mass distributions for decays of the form 0^{-+}->l^+l^-\gamma, which are important radiative corrections to the purely leptonic decays 0^{-+}->l^+l^-. Our approach uses the loop diagrams…
We review the pair-production and decay of selectrons in $e^-e^-$ collisions and show how the standard model backgrounds can be virtually eliminated with polarized beams. The exceedingly simple analysis involved and the large sample of…
Searches for lepton-flavor-violating decay of a tau lepton to a lighter mass lepton and a photon have been performed with the entire dataset of (963 +- 7) x 10^6 tau decays collected by the BaBar detector near the Upsilon(4S), Upsilon(3S)…
The pure lepton decay of the polarized muon is considered, accounting for a new tensor interaction which is outside of the Michel local interactions. This interaction leads to new energy distribution and polarization of the final charged…
Lepton flavor violation is one of the cleanest probes of physics beyond the standard model. In this work, we explore the sensitivity of the process $e^+ e^- \to \tau \mu$ to new physics above the TeV scale at the proposed circular…
We propose a model to explain several muon-related experimental anomalies and the abundance of dark matter. We introduce an vector-like exotic lepton that form an iso-doublet and three right-handed Majorana fermions as an iso-singlet. A…
Dark Matter and Dark Energy are two of the most fundamental open questions in physics today. The existence of a light dark-force mediator has been hypothesized as a possible explanation for several unexplained physical phenomena. A new…
A large $\mu^-$ polarization was achieved in muonic Bi atoms with the help of the strong hyperfine field in a polarized nuclear target. Using $^{209}$Bi nuclei polarized to ($59\pm9$)% in ferromagnetic BiMn, we observed a $\mu$-$e$ decay…
We sketch a novel method to search for light di-leptonic resonances by exploiting precision measurements of Drell-Yan production. Motivated by the recent hints of lepton flavour universality violation in $B \to K^{\ast} \ell^+ \ell^-$, we…
It is shown that the difference in the distributions of positive ($\mu^+$) and negative charged leptons ($\mu^-$) in reactions $\gamma \gamma \to \mu^+\mu^-+\nu\bar\nu$ and $\gamma \gamma \to W^\pm\mu^\mp +\nu(\bar\nu)$ at $\sqrt{s}>200$…