Related papers: Boosted tau lepton as a microscope and macroscope

We propose a radiative lepton model, in which the charged lepton masses are generated at one-loop level, and the neutrino masses are induced at two-loop level. On the other hand, tau mass is derived at tree level since it is too heavy to…

Some important aspects of hadronic tau decays are reviewed: the determination of alpha_s from the inclusive tau hadronic width, the measurement of |V_{us}| through the Cabibbo-suppressed decays of the tau, and the theoretical description of…

Many theoretical models, like the Standard Model or SUSY at large tan(beta), predict Higgs bosons or new particles which decay more abundantly to final states including tau leptons than to other leptons. At the energy scale of the LHC, the…

Very little is known about the mass spectrum of fermions in the standard model. In this talk, I point out that in the simplest extension of the standard model, in which all right-handed fields are singlets, it is quite possible that a…

A large lepton asymmetry in the Universe is still a viable possibility and leads to many interesting phenomena such as gauge symmetry nonrestoration at high temperature. We show that a large lepton asymmetry changes the predicted cosmic…

Using the effective Lagrangian formalism, the anomalous magnetic and electric dipole moments of the tau-lepton in the $\mu^{+}\mu^{-} \rightarrow \mu^{+}\gamma^{*} \gamma^{*} \mu^{-}\rightarrow \mu^{+}\tau \bar{\tau}\mu^{-}$ process at the…

Dark matter charged under a new gauge sector, as motivated by recent data, suggests a rich GeV-scale "dark sector" weakly coupled to the Standard Model by gauge kinetic mixing. The new gauge bosons can decay to Standard Model leptons, but…

The mass of the $\tau$-lepton has been measured in the decay modes $\tau \to 3\pi \nu_\tau$ and $\tau \to 3\pi \pi^0\nu_\tau$ using a pseudomass technique. The preliminary result is $1776.71\pm 0.25 {(stat)} \pm 0.62 {(syst)}$ MeV. The…

This Letter reports the observation of $\tau$-lepton pair production in ultraperipheral lead-lead collisions, $\text{Pb+Pb} \to \text{Pb}(\gamma\gamma \to \tau\tau)\text{Pb}$, and constraints on the $\tau$-lepton anomalous magnetic moment,…

We search for lepton-flavor-violating and lepton-number-violating tau decays into a lepton (l = electron or muon) and two charged mesons (h, h' = pion or Kaon) using 854 fb^{-1} of data collected with the Belle detector at the KEKB…

This article reviews and updates the Standard Model prediction of the tau lepton g-2. Updated QED and electroweak contributions are presented, together with new values of the leading-order hadronic term, based on the recent low energy e+ e-…

New vectorlike fermions that mix with the third generation can significantly affect the tau and b Yukawa couplings. Consistent with precision electroweak measurements, the width of the Higgs boson to tau tau, b b can be reduced by O(1) with…

We confront the indications of lepton flavor universality (LFU) violation observed in semi-tauonic $B$ meson decays with new physics (NP) searches using high $p_T$ tau leptons at the LHC. Using effective field theory arguments we correlate…

One of the key assumptions of the Standard Model of fundamental particles is that the interactions of the charged leptons, namely electrons, muons, and taus, differ only because of their different masses. While precision tests have not…

The experimental discovery of large nu_mu-nu_tau mixing indicates that analogous mixing in the charged lepton sector could be substantial. We consider the possibility that if a high intensity muon beam, perhaps at the early stages of a muon…

Long-lived particles (LLPs), i.e., particles with macroscopic lifetimes $\tau>10$~ns, appear in various extensions of the Standard Model (SM) that address fundamental questions like the particulate nature of dark matter or baryogenesis. The…

We propose a new method to probe the magnetic and electric dipole moments of the $\tau$ lepton using precise measurements of the differential rates of radiative leptonic $\tau$ decays at high-luminosity $B$ factories. Possible deviations of…

The BaBar collaboration has accumulated over 400 million tau-pairs which can be used to study charged leptonic and hadronic weak currents to unprecedented precision. This note presents results on lepton universality, measurements of |V_us|,…

Tau leptons can have lepton-flavor-violating (LFV) couplings to a muon or an electron and an Axion-Like Particle (ALP). ALPs are pseudo Nambu-Goldstone bosons associated with spontaneously broken global U(1) symmetries. LFV ALPs have been…

We calculate the squared matrix element for the process e+ e- --> tau+ tau- gamma allowing for anomalous magnetic and electric dipole moments at the tau tau gamma vertex. No interferences are neglected and no approximations of light fermion…