Charged LFV in a low-scale seesaw mSUGRA model

We investigate the influence of the boundary conditions of minimal supergravity (mSUGRA) on the supersymmetric mechanism for lepton flavour violation (LFV) proposed recently [1], within the framework of the MSSM extended by TeV-scale singlet heavy neutrinos. We find that the consideration of the mSUGRA boundary condition may increase the branching ratios of the muon and tauon decaying into three charged leptons by up to a factor of 5, whereas the corresponding branching ratio for their photonic decays remains almost unchanged.Comment: 6 pages, 3 figures. Prepared for the Proceedings of the 11th International Workshop on Tau Lepton Physics, Manchester, UK, September 13-17, 2010. Presented by A. Ilakova

Motion of distant objects in the Universe

We give a brief survey of investigations of the structure of the Universe and of its expansion, for educational purposes. As we know it today, the size of the Universe is immense, enormous numbers of galaxies have been found in it, and in each galaxy enormous numbers of stars. The galaxies move from us at very high speeds, some of the more distant ones at speeds comparable to the velocity of light. Many theories have been developed to explain the vast amount of data that have been obtained by astronomical observations. We give a simplified theory of the cosmic expansion and present results of three models for the cosmic scale function R(t): the constant rate of expansion, the accelerated expansion and the constant Hubble parameter models

Production and Polarization Effects in Some Tau-Lepton Decays

The conditions for the independence of decays of the spin-1/2 resonances on the production mechanism of the resonances and on polarizations of the incoming and outgoing particles are derived and applied in the case of several tau-lepton decays. The necessity for inclusion of the influence of the production mechanism in the evaluation of the lepton flavour violating decays is stressed.Comment: Invited Talk at the Seventh International Workshop on Tau Lepton Physics (TAU02), Santa Cruz, CA, USA, Sept. 2002, 6 pages LaTeX; One typo corrected, a note added, one reference adde

Comment on "the decoupling of heavy sneutrinos in low-scale seesaw models"

The authors of a recent communication [arXiv:1312.5318] claim to have traced an error in the existing literature regarding the evaluation of the one-loop right-handed sneutrino contributions to lepton-flavour-violating observables in supersymmetric low-scale seesaw models. In this short note, we emphasize that contrary to those authors' claim, our paper [arXiv:1212.5939] contains no such a flaw, and both our analytical and numerical results exhibit the expected decoupling property of the heavy sneutrinos in the Z-penguin graphs.Comment: 2 pages, 1 figur

Lepton flavor violation in the standard model extended by heavy singlet Dirac neutrinos

Low-energy neutrinoless lepton flavor-violating (LFV) processes are studied in an extension of the standard model (SM) by heavy SU(2)×U(1) singlet Dirac neutrinos. An upper-bound procedure is elaborated for the evaluation of amplitudes. A comment on the extraction of heavy-neutrino mixings from astrophysical observations is given. For processes not treated in the model applied, the formalism for evaluating the branching ratios (BR’s) is presented. The processes previously studied in the model are examined and some results are improved. The structure of the amplitudes and BR’s as well as the relations between BR’s of different LFV processes are examined. The decoupling of heavy neutrinos is discussed and it is explicitly shown that very heavy neutrinos decouple when the upper-bound procedure is applied. The LFV decays are shown to be unsuitable for finding upper bounds on “diagonal” LFV parameters. Comparing the theoretical BR’s with curent experimental upper bounds, a few processes interesting for the search for LFV are proposed. Particularly, B-meson LFV processes are suggested for the search of LFV in future B factories

Artificial photosinthesis

U ovom radu opisana je umjetna fotosinteza. Od njenog početka istraživanja do danas. Dane su matematičke jednadžbe te postupak oponašanja umjetne fotosinteze kao i konkretne slike. Navedeni su i fotosustavi koji su najodgovorniji za uspjeh ovog istraživanja. Ako ovaj istraživački rad uspije, imati ćemo otvoren put k širokoj i ekonomski isplativoj upotrebi vodika kao energenta.This paper describes artificial photosynthesis, from its beginning to the present research. It shows mathematical equations and process imitation artificial photosynthesis as well as images. Also are given photosystems who are most responsible for the success of this research. If this research succeeds , we will have open path to a wide and low-cost use of hydrogen as an energy source.

Single-point observation of rapidly moving objects

We study the kinematical problem of observation of motion of objects that move at velocities comparable to the velocity of signals which are used to determine the velocity and distance of the objects. The main purpose of this work is to demonstrate the importance of time delay between the emission of signals and their reception at the observation point. The simplest cases are considered, i.e., rectilinear motion and assuming the observational point at the path of the moving object. Sound and light signals are considered to transmit the information on the motion. The results relating to the motion at constant velocity and for the acceleration due to a constant force are presented