相关论文: Limits on $\nu_{\tau}$ mass by DELPHI

A search for pair-produced doubly charged Higgs bosons has been performed using the data collected by the DELPHI detector at LEP at centre-of-mass energies between 189 and 209 GeV. No excess is observed in the data with respect to the…

We perform a measurement of the branching fractions for tau -> l gamma nu anti-nu (l= e, mu) decays for a minimum photon energy of 10 MeV in the tau rest frame using 430 fb^-1 of e^+ e^- collisions collected at the center-of-mass energy of…

We investigate the dipole moments of the tau- neutrino at high-energy and high luminosity at linear electron positron colliders, such as CLIC or ILC through the analysis of the reaction $e^{+}\, e^{-}\rightarrow \nu\, \bar \nu \,\gamma$ in…

Using a sample of 12.2 million $\tau$-lepton pairs produced by $e^+e^-$ annihilation at $\sqrt{s}\sim 10.6 $GeV and collected by the CLEO detector, we search for and set limits on CP violation in $\tau$-lepton decays. For each event, we…

Using about 3.9 million hadronic Z decays from e+e- collisions recorded by the OPAL detector at LEP at centre-of-mass energies near MZ the branching ratio for the decay D_s -> tau nu_tau has been measured to be (7.0 +/- 2.1(stat) +/- 2.0…

Although neutrinos are probably the most abundant particles of the universe their mass is not yet known. Oscillation experiments have proven that at least one of the neutrino mass states has m_{i}>0.05 eV while various interpretations of…

We determine the restrictions imposed by primordial nucleosynthesis upon a heavy tau neutrino, in the presence of nu-tau annihilations into Majorons, as expected in a wide class of particle physics models of neutrino mass. We determine the…

Spin correlations for tau lepton decays are included in the Pythia 8 event generation software and the spin correlations for the decays of tau leptons produced from electroweak and Higgs bosons are calculated. Decays of the tau lepton using…

This thesis presents a study of the decays $\tau\rightarrow e\nu\overline{\nu}$ identified after a selection of $\tau^+\tau^-$ events produced in $e^+e^-$ collisions at LEP. These collisions, predominantly mediated by a $Z^0$ boson, offer a…

Neutrinos mix and have mass differences, so decays from one to another must occur. But how fast? The best direct limits on non-radiative decays, based on solar and atmospheric neutrinos, are weak, $\tau \gtrsim 10^{-3}$ s ($m$/eV) or much…

Tau lepton as one of three elementary leptons in nature, the measurement of its mass has ever been performed since its discovery. The present relative accuracy is already at the level of better than 10 to minus 4 and more effects are still…

We present here up-to-date neutrino mass limits exploiting the most recent cosmological data sets. By making use of the Cosmic Microwave Background temperature fluctuation and polarization measurements, Supernovae Ia luminosity distances,…

If heavy neutrinos with mass $m_{\nu_{H}}\geq$2$ m_e $ are produced in the Sun via the decay ${^8\rm{B}} \rightarrow {^8\rm{Be}} + e^+ + \nu_H$ in a side branch of pp-chain, they would undergo the observable decay into an electron, a…

An ansatz for mass matrix was recently proposed for charged leptons, predicting (in its diagonal approximation) $m_\tau\simeq1776.80$ MeV from the experimental values of $m_e$ and $m_\mu$, in agreement with $m_\tau^{exp}=…

Recent theoretical work has explored dark matter accumulation in the Earth and its drift towards the center of the Earth that, for the current age of the Earth, does not necessarily result in a concentration of dark matter ($\chi$) in the…

We study the prospects of detecting the signal in the stau neutralino co-annihilation region at the LHC using tau leptons. The co-annihilation signal is characterized by the stau and neutralino mass difference (dM) to be 5-15 GeV to be…

Inspired by the neutrino oscillations data, we consider the exact $\mu-\tau$ symmetry, implemented at the level of the neutrino mass matrix, as a good initial framework around which to study and describe neutrino phenomenology. Working in…

The effective electron neutrino mass can be determined by analyzing the endpoint region of the $^{163}$Ho electron capture spectrum, provided a measurement with high energy resolution and high statistics using calorimetric techniques. Here,…

Evidence of a heavy neutrino, $\nu_H$, in the $K^+\to\mu^+\nu_H$ decays was sought using the E949 experimental data with an exposure of $1.70\times 10^{12}$ stopped kaons. With the major background from the radiative…

Recently an upper bound on the rate of the lepton number violating decay $K^+\to \mu^+\mu^+\pi^-$ has been significantly reduced by the E865 experiment at BNL and further improvement is expected in the near future. We study this process as…