Related papers: Regularities in electromagnetic decay widths
Recent spectroscopic measurements in a number of strongly correlated metals that exhibit non-Fermi liquid like properties have observed evidence of anomalous frequency and momentum-dependent charge-density fluctuations. Specifically, in the…
We consider mass-deformed conformal gauge theories (mCGT) and investigate the scaling behaviour of hadronic observables as a function of the fermion mass. Applying renormalization group arguments directly to matrix elements, we find m_H ~…
In the Standard Model, lepton universality refers to the identical electroweak gauge interactions among charged leptons. The measurement of the branching ratio $R_{e / \mu} = \frac{\Gamma(\pi\rightarrow\ e…
We introduce the differential and the total decay widths of a resonant (Gamow) state decaying into a continuum of stable states. When the resonance has several decay modes, we introduce the corresponding partial decay widths and branching…
We use a covariant supermultiplet theory to determine the primary coupling constant associated with several types of two-body meson decay. Despite the diverse range of decays considered the primary coupling constant is surprisingly uniform.…
This paper addresses the role of Large Extra Dimensions in some flavor changing neutral current (FCNC) driven processes. In particular we have investigated radiative decays of charged leptons within models with only one universal extra…
The radiative meson decays $V\to P\gamma$ and $P\to \gamma\gamma$ are analyzed using the quark triangle diagram. Experimental data yield well determined estimates of the universal quark-antiquark-meson couplings $g_{Vq\bar{q}'}$ and…
Leptonic decay widths and leptonic decay constants of light vector mesons and weak leptonic decay widths and weak decay constants of light and heavy pseudoscalar mesons have been studied in a field- theoretic framework based on the…
The evaluation, systematic analysis and numerical study of the semileptonic $\tau$-lepton decays with two mesons in the final state has been made in the frame of the standard model extended by right handed neutrinos. In the analysis,…
The MEGA experiment, which searched for the muon- and electron-number violating decay \mu -> e + \gamma, is described. The spectrometer system, the calibrations, the data taking procedures, the data analysis, and the sensitivity of the…
The radiative decays $V\to S\gamma$ and $S\to V\gamma$ with $V=\rho, \omega, \phi$ and $S=a_0, \sigma, f_0$ are calculated within the framework of the Linear Sigma Model. Current experimental data on the $\phi\to f_0\gamma$ and…
In a wide class of models -- including the standard model -- flavor-changing neutral currents are suppressed by an approximate chiral symmetry of the low-energy lagrangian. This symmetry allows the derivation of general relations among…
We reconsider the QCD predictions for the radiative decay $B\to \gamma \ell \nu_\ell$ with an energetic photon in the final state by taking into account the $1/E_\gamma, 1/m_b$ power-suppressed hard-collinear and soft corrections from…
In the canonical seesaw mechanism of neutrino mass, lepton number is only multiplicatively conserved, which enables the important phenomenon of leptogenesis to occur, as an attractive explanation of the present baryon asymmetry of the…
The possibility of grand unification of the standard model (SM) with fermion spectrum extended to include mirror fermions is examined. SM gauge couplings do not automatically unify. SO(10) grand unification is studied with one intermediate…
We study the growth of matter density perturbations delta_m for a number of viable f(R) gravity models that satisfy both cosmological and local gravity constraints, where the Lagrangian density f is a function of the Ricci scalar R. If the…
We present a unified picture which studies simultaneously the gamma gamma-->pi^+ pi^-, pi^0 pi^0, K^+ K^-, K^0 bar{K}^0, pi^0 eta reactions up to about sqrt(s)=1.4 GeV reproducing the experimental cross sections. The present work implements…
An analysis of radiative decays of the neutrinos $\nu_j\to \nu_l \gamma$ is discussed in MSSM extensions with a vector like lepton generation. Specifically we compute neutrino decays arising from the exchange of charginos and charged…
We discuss all possible fermion field renormalization prescriptions in conventional field renormalization meaning and mainly pay attention to the imaginary part of unstable fermion Field Renormalization Constants (FRC). We find that…
The radiative decay of the massive neutrino $\nu_i \rightarrow \nu_j \gamma$ in a circularly polarized electromagnetic wave is investigated within the Standard theory with lepton mixing. The decay probability in the wave field does not…