Related papers: Alpha_s from Tau Decays
The analysis of correlations between fluctuations of alpha- and beta-decay rates for different radio-active elements is carried out. These fluctuations exceed significantly errors of measurements in many cases. They have the periodical…
To reduce the current theory uncertainties a novel way to determine the $B_c$ lifetime, $\tau_{B_c}$, is proposed. Taking the difference of the $B_c$, and $B$ and $D$ meson decay rates eliminates the leading contributions from the…
We study the $L\to l l' l' \nu_l \nu_L$ decays ($L=\tau,\mu$; $l,l'=\mu,e$) in the Standard Model (SM) and in the effective field theory (EFT) description of the weak charged current at low energy, both for polarized and unpolarized $L$,…
The Belle and Babar experiments have measured the branching fractions for B+ -> tau+ nu and Ds+ -> mu+ nu decays. From these measurements one can extract the B+ and Ds+ decay constants, which can be compared to lattice QCD calculations. For…
Experimental studies of B -> D^(*) tau nu decays, are reported. The results are based on large data samples collected at the Upsilon(4S) resonance with the Belle detector at KEKB and the BABAR detector at the SLAC PEP-II asymmetric energy…
We report on the recent results of searches for lepton-flavor-violating tau decays as well as lepton-number-violating B decays with the world-highest data samples accumulated at the Belle.
Double-pinched Borel-Laplace sum rules are applied to ALEPH $\tau$-decay data. For the leading-twist ($D=0$) Adler function a renormalon-motivated extension is used, and the 5-loop coefficient is taken to be $d_4=275 \pm 63$. Two $D=6$…
The recent results from Belle of the $\tau^-\to\nu_\tau\pi^-e^+e^-$ analysis has incentivated us to make a reanalysis of a former work where the Structure Dependent parts are obtained using Resonance Chiral Theory. Here we rely on the same…
The recent measurement of the tau -> Ks pion nu_tau spectrum by the Belle Collaboration provides the frame to set forth a theoretical description of the decay, which is based on the contributing vector F_+(s) and scalar F_0(s) form factors.…
Within the resonance chiral theory, we have studied the process of a tau lepton decaying into a vector resonance plus a pseudo-Goldstone meson and a tau neutrino. Two kinds of processes are discussed: (a) tau- --> (rho pi-,omega pi-, phi…
Theoretical estimates of $\alpha$-decay half lives of several nuclei in the decay from element 113 are presented. Calculations in a WKB framework using DDM3Y interaction and experimental Q-values are in good agreement with the experimental…
Recent results of a high-statistics study of tau lepton properties and decays at B factories are reviewed. We discuss measurements of tau lifetime, branching fractions, and spectral functions for several hadronic tau decay modes with…
Within an effective field theory framework, we discuss the possibility to discriminate among different operators that contribute to lepton flavor violating (LFV) tau decays. Correlations among decay rates in different channels are shown to…
In this talk, I summarize the recent determinations in Ref.[1] of the QCD condensates and $\alpha_s$ within the SVZ expansion using the ratio of Laplace sum rule (LSR) ${\cal R}_{10}^A(\tau)$ and $\tau$-like moments ${\cal R}_{n,A},\, {\cal…
We make some observations on the decay rates of the Fourier coefficients of cusp functions.
We report on a recent calculation of the top decay rate up to order \alpha_s^2. It is based on asymptotic expansions of the off-shell top propagator, followed by a Pad\'e approximation in order to reach the physically relevant point…
Next-to-next-to-leading contributions to the cross section sigma(e+e- -> tau+tau-) at energies close to threshold are analysed, taking into account the known non-relativistic effects and O(alpha^2) corrections. The numerical changes with…
New recent experimental $\alpha$ decay half-lives have been compared with the results obtained from previously proposed formulas depending only on the mass and charge numbers of the $\alpha$ emitter and the Q$\alpha$ value. For the heaviest…
The experimental results of the \babar\ and Belle collaborations are presented on the measurement of the branching ratio for the decay $B^\pm \to \tau^\pm \nu$, and the limits set on the branching ratios for the decays $B^\pm \to e^\pm \nu,…
In order to determine the fundamental MSSM parameters M_1, M_2, \mu and \tan\beta the tau polarization from stau decays can be explored as a `bridge' between the gaugino/higgsino and the stau sector in particular in the high \tan\beta…