Lepton flavor violating leptonic and semileptonic decays of charged leptons in the minimal supersymmetric standard model

We consider the leptonic and semileptonic (SL) lepton-flavor violating (LFV) decays of the charged leptons in the minimal supersymmetric standard model (MSSM) with right-handed neutrinos. The parameters of the MSSM model are determined in the framework of the minimal supersymmetric SO(10) GUT model assuming the minimal supergravity model of supersymmetry breaking. The free parameters of the model are constrained adopting the WMAP cold dark matter constraint and adjusting the neutrino oscillation data. So constrained, the SO(10) GUT model gives a definite prediction for the Dirac-neutrino Yukawa matrix, which induces all LFV effects in the MSSM model through renormalization group equations of soft SUSY breaking parameters. A very detailed numerical analysis has been made to define numerically all MSSM parameters necessary for the evaluation of the LFV amplitudes. The basic LFV amplitudes in MSSM were rederived and improved. The formalism for the evaluation of all SL LFV amplitudes is given. Numerical results for dominant SL LFV branching ratios, the anomalous magnetic moment of the muon and the ℓ→ℓ’γ branching ratios are given.     

The μ-dependence of the effective weak Hamiltonian andK→2π amplitudes in chiral-bag model

This paper studies the μ-dependence of the operator matrix elements. Although the μ-dependence must in principle cancel as illustrated in the paper by using a simple pedagogical model, in practice the choice of μ markedly influences the theoretical predictions forK→2π decays.     

Ground state of the quasi-1D compound BaVS3 resolved by resonant magnetic x-ray scattering

Resonant magnetic x-ray scattering near the vanadium L2,3-absorption edges has been used to investigate the low temperature magnetic structure of high quality BaVS3 single crystals. Below T(N)=31 K, the strong resonance revealed a triple-incommensurate magnetic ordering at the wave vector (0.226 0.226 ξ) in hexagonal notation, with ξ=0.033. The azimuthal-angle dependence of the scattering signal and time-dependent density functional theory simulations indicate an antiferromagnetic order within the ab plane with the spins polarized along a in the monoclinic structure.     

CP violation induced by heavy Majorana neutrinos in the decays of Higgs scalars into top-quark, W - and Z-boson pairs

We analyze the possibility of CP violation induced by heavy Majorana neutrinos in the decays of the Higgs particle into top-quark, W - and Z-boson pairs. In the framework of various “see-saw” models with interfamily mixings, we find that Majorana neutrinos may give rise to sizable CP-odd observables at the one-loop electroweak order. Numerical estimates of these CP-violating effects that may be detected in high-energy colliders are presented.     

Density-functional study of the cycloaddition of acrylonitrile on the Si(100) surface

Using a density functional approach, we have explored the cycloaddition of acrylonitrile on the Si(100) surface. The buckling of the surface dimers characteristic for the (2x1) reconstructed surface is shown to favor structures with a dipolar moment such as the resonant form of acrylonitrile with cumulative double bonds. The bond of acrylonitrile via a single C atom is a possible intermediate leading to the nitrile structure of the adsorbed molecule.     

Directional correlation studies in the decay of177gLu

Directional gamma-gamma correlations of the strong 208.4–112.9 keV and of the weak 71.6–249.7 keV cascade transitions in the decay of^177gLu have been measured. The correlation coefficientsA ₂₂=?0.208±0.012 of the strong andA ₂₂=?0.105±0.005 of the weak cascade have been determined. The mixing ratioE2/M1 of ?3.7±0.3 for the 112.9 keV transition and theM2/E1 of ?0.0173±0.0065 for the 71.6 keV transition have been obtained. The deducedM2 admixture in the 71.6 keV transition is in good agreement with the theoretical estimates of Weisskopf and of Nilsson.

     

BaVS3 probed by V L edge x-ray absorption spectroscopy

Polarization dependent vanadium L edge x-ray absorption spectra of BaVS(3) single crystals are measured in the four phases of the compound. The difference between signals with the polarizations E perpendicular to c and E is parallel to c (linear dichroism) changes with temperature. Besides increasing the intensity of one of the maxima, a new structure appears in the pre-edge region below the metal-insulator transition. More careful examination brings to light that the changes start already with pretransitional charge density wave fluctuations. Simple symmetry analysis suggests that the effect is related to rearrangements in the E(g) and A(1g) states, and is compatible with the formation of four inequivalent V-sites along the V-S chain.