相关论文: Leptonic Photons and Nucleosynthesis
We examine the production and decay of extremely heavy magnetically charged leptons, (tau_g and mu_g), to their own very heavy mu_g and e_g plus their own new species of neutrinos, nu_g and nubar_g, at some time early in the universe which…
The observed constraints on the variability of the proton to electron mass ratio $\mu$ and the fine structure constant $\alpha$ are used to establish constraints on the variability of the Quantum Chromodynamic Scale and a combination of the…
We compute primordial light-element abundances for cases with fine structure constant alpha different from the present value, including many sources of alpha dependence neglected in previous calculations. Specifically, we consider…
Minimal extensions of the Standard Model that are motivated by grand unified theories or superstring models with an E_6 symmetry can naturally predict heavy neutrinos of Dirac or Majorana nature. Such heavy neutral leptons violate the de-…
The lepton flavour violating charged lepton decays mu to e + gamma and thermal leptogenesis are analysed in the minimal supersymmetric standard model with see-saw mechanism of neutrino mass generation and soft supersymmetry breaking terms…
Big Bang Nucleosynthesis can provide, via constraints on the expansion rate at that time, limits on possible variations in Newton's Constant, $G$. The original analyses were performed before an independent measurement of the…
Decays of B mesons to states involving tau leptons can be used as a tool to search for the effects of new physics, such as those involving a charged Higgs boson. The experimental status of the decays B -> tau nu and B -> D^(*) tau nu is…
Standard Model contributions to the electron, muon, and tau lepton anomalous magnetic moments, a_l=(g_l-2)/2, are reviewed and updated. The fine structure constant is obtained from the electron g_e-2 and used to refine the QED contribution…
We study if the neutrino mixing parameters suggested by the atmospheric neutrino anomaly imply chemical equilibrium between mu- and tau-flavored leptons in a supernova (SN) core. The initial flavor-conversion rate would indeed be fast if…
Central nucleon-nucleon potentials involving forbidden states are obtained for the Gaussian, exponential, and Yukawa type. The parameters of interaction are obtained by fitting the scattering phase shifts for energies up to 500 MeV,…
I will summarize theoretical issues in Working Group 1 at Nufact'01. Although there may not be complete agreement yet on the exact optimum baseline $L$ and the muon energy $E_\mu$ for measurements of the CP phase at a neutrino factory, all…
U(1)-family symmetries have led to successful predictions of the fermion mass spectrum and the mixing angles of the hadronic sector. In the context of the supersymmetric unified theories, they further imply a non-trivial mass structure for…
The rare kaon decay $K^+ \ra \pi^- \mu^+ \mu^+$ is violating lepton number by two units and is investigated within the context of Majorana neutrino masses. Using a new upper bound for this decay from E865 an upper limit on the effective…
The electron would decay into a photon and neutrino if the law of electric charge conservation is not respected. Such a decay would cause vacancy in closed shells of atoms giving rise to emission of x-rays and Auger electrons. Experimental…
We show that in the presence of sufficiently strong $\nu_\tau$ annihilations to majorons, primordial nucleosynthesis constraints can not rule out any values of the $\nu_\tau$ mass up the present laboratory limit.
We speculate about the possible interpretations of the recently observed excess in the $h \to \tau \mu$ decay. We derive a robust lower bound on the Higgs boson coupling strength to a tau and a muon, even in presence of the most general new…
We constrain energy spectra of supernova neutrinos through the avoidance of an overproduction of the 11B abundance during Galactic chemical evolution. In supernova nucleosynthesis calculations with a parametrized neutrino spectrum as a…
Recent determinations of the deuterium abundance, $^2$H/H, in high redshift Lyman limit hydrogen clouds challenge the usual picture of primordial nucleosynthesis based on \lq\lq concordance\rq\rq\ of the calculated light element ($^2$H,…
By combining experimental constraints from atmospheric and solar neutrino oscillations and the tritium beta decay endpoint, we infer upper limits of 4.4 eV on the $\nu_\mu$ and $\nu_\tau$ masses, if the universe consists of three neutrinos.…
We study the effects induced by new neutral fermions below their mass threshold, due to their possible mixing with the standard neutrinos. We use as experimental constraints the recent results on lepton universality, together with the…