Related papers: How the tau-lepton mass can be understood
For integer values of its free parameter, an empirical formula reproduces fairly well the mass values of the $\mu$ and $\tau$ leptons as if they were excited states of the electron. Trident production might possibly be due to constituent…
An energy scan near the $\tau$ pair production threshold has been performed using the BESIII detector. About $24$ pb$^{-1}$ of data, distributed over four scan points, was collected. This analysis is based on $\tau$ pair decays to $ee$,…
Why the charged lepton mass formula m_e +m_\mu +m_\tau = {2/3} (\sqrt{m_e}+\sqrt{m_\mu} +\sqrt{m_\tau})^2 is mysterious is reviewed, and guiding principles to solve the mystery are presented. According to the principles, an example of such…
By analogy with an effective model of charged-lepton mass matrix that, with the inputs of $m^{exp}_e $ and $m^{exp}_\mu$, predicts (in a perturbative zero order) $m_\tau = 1776.80 $ MeV close to $m^{exp}_\tau = 1777.03^{+0.30}_{-0.26}$ MeV,…
The tau lepton lifetime is measured with the L3 detector at LEP using the complete data taken at centre-of-mass energies around the Z pole resulting in tau_tau = 293.2 +/- 2.0 (stat) +/- 1.5 (syst) fs. The comparison of this result with the…
The charged lepton mass relation $K \equiv (m_e +m_\mu+m_\tau)/(\sqrt{m_e} %+\sqrt{m_\mu} +\sqrt{m_\tau})^2= 2/3 $ is excellently satisfied by observed masses (pole masses). However, the formula $K=2/3$ should be never satisfied with the…
We present a measurement of the $\tau$-lepton mass using a sample of about 175 million $e^+e^- \to \tau^+\tau^-$ events collected with the Belle II detector at the SuperKEKB $e^+e^-$ collider at a center-of-mass energy of…
The first complete calculation of the quadratic quark mass correction to the correlator of the two currents relevant for the strangeness-changing semihadronic tau-decay rate is presented including its real part at the four-loop level. This…
I examine the possibility that the third generation fermion masses are determined by an exact fixed point of the minimal supersymmetric SU(5) model. When one-loop supersymmetric thresholds are included, this unified fixed point successfully…
Three important QCD-related aspects of the $\tau$ and $\mu$ dynamics are reviewed: the determination of the strong coupling from the hadronic tau decay width, leading to the updated value $\alpha_s(m_\tau^2) = 0.331 \pm 0.013$; the…
Koide has pointed out that the mass relation $m_e + m_{\mu} + m_{\tau} = {2 \over 3}(\sqrt{m_e} + \sqrt{m_{\mu}} + \sqrt{m_{\tau}})^2 $ is consistent with the most recent measurements of the tau lepton mass. We point out that this relation…
The measurements of the mean lifetime of the tau lepton are reviewed. The conditions for measuring the lifetime at various e+e- colliders are compared and the analysis methods are briefly described. The new developments since the previous…
We derive empirical relationships among elementary fermion masses based on relatively simple exponential formulae involving quantum numbers for the electromagnetic and strong interactions, with a weak correction factor motivated by a simple…
In this work radiative corrections in the total hadronic decay rate of the tau-lepton and some moments of its differential distributions are studied employing perturbative QCD and the operator product expansion. We calculate quadratic quark…
The reconstruction of tau-pair production, $e^{+}e^{-} \to \tau^{+}\tau^{-}$, from the subsequent 3-prong ($\tau^{+} \rightarrow \pi^{+} \pi^{-} \pi^{+} \bar{\nu}_{\tau}$) and 1-prong ($\tau^{-} \to \ell^{-} \bar{\nu}_{\ell} \nu_{\tau}$,…
Treating the Koide equation and another efficient charged-lepton mass formula (having the form of a mass sum rule) as a system of two mathematically independent algebraic equations for three charged-lepton masses, we predict the tauon mass…
The top quark mass is measured in the $t\bar{t}\to$ dilepton channel (lepton $= e, \mu$) using ATLAS data recorded in the year 2012 at the LHC. The data were taken at a proton--proton centre-of-mass energy of $\sqrt{s}=$ 8 TeV and…
The top quark mass is measured using a template method in the $t\bar{t}\to$ lepton+jets channel (lepton is $e$ or $\mu$) using ATLAS data recorded in 2012 at the LHC. The data were taken at a proton-proton centre-of-mass energy of…
The tau lepton can be more composite than naively expected in models of strong electroweak symmetry breaking with tri-bimaximal lepton mixing. New leptonic resonances required by custodial symmetry, the tau custodians, can then be the first…
The mass relations among respective quark family members are predicted and similar mass relation for the lepton family member are obtained. The volume of the volume element is also calculated which is (3/2)^(1/2).