[en] Measurements of the transverse momentum distribution of electroweak gauge bosons W and Z are one of the prior duties at the LHC. These measurements provide one of the most crucial tests of Standard Model, in particular, the QCD calculations for hadron colliders, which have different approaches for different ranges of the spectrum. In addition, data on W and Z production is an important tool in searching for possible new particles, i.e., new heavy lepton doublets, Higgs boson, or supersymmetric partners of existing particles. In this thesis we describe a measurement of the W transverse momentum (P_T"W) distribution produced by proton-proton collisions at the LHC with the ATLAS detector. The W signature is searched via its leptonic decay modes. Because of the neutrino in the final state which is undetectable, the P_T"W must be reconstructed as the hadronic recoil measured by summing vectorially the transverse energies deposited in the calorimeter excluding those of lepton(s). We present here an algorithm of hadronic recoil reconstruction in W, Z events.The analysis is performed using the data produced at √ = 7 TeV during 2010, corresponding to 31 pb"-"1 of integrated luminosity, in which 125 kW → μν and 105 kW → eν candidates are selected. In comparison with previous measurements, this measurement at LHC with more number of events used gives a better precision and allows to extend the range as well as apply fully correction accounting for the bin-to-bin correlation. In the measurements, the W propagator is defined as the baseline quantity to be measured. This allows for a combination of the final results to get a better statistic. The resulting combined spectrum is compared to predictions modeled by different Monte Carlo event generators and calculated from fix-order perturbative QCD by different programs. The predictions from event generators such as ALPGEN + HERWIG, PYTHIA, RESBOS, and SHERPA match the data within 20% over the entire P_T"W range. Both fixed-order perturbative QCD predictions from the DYNNLO and MCFM programs predict fewer events at high P_T"W at θ(α_s"2) but the agreement with the measured distribution is significantly improved by the θ(α_s"2) calculations. (author)

[en] A Higgs sextet is introduced in order to generate Dirac and Majorana neutrino masses in the 331 model with right-handed neutrinos. As will be seen the present sextet introduction leads to a rich neutrino mass structure. The smallness of neutrino masses can be achieved via, for example, a seesaw limit. The fact that the masses of the charged leptons are not effected by their new Yukawa couplings to the sextet is convenient for generating small neutrino masses

[en] Neutrino masses and mixing in an extended standard model acquiring an A4 flavour symmetry are considered. The corresponding three-neutrino mixing matrix obtained via a perturbative method allows to determine the Dirac CP violation phase (δ_C_P) as a function of the mixing angles (θ_1_2, (θ_2_3, (θ_1_3). Then, numerical values and distributions of δ_C_P are given. The latter values are quite close to the global fits of the experimental data for both the normal ordering and inverse ordering of the neutrino masses. (author)

[en] In this paper, we study the combined sensitivity of T2K-II and NOvA, the world leading long-baseline neutrino oscillation experiments, to CP violation in lepton sector. By operating until the year 2026, T2K-II is expected to collect a total exposure of 20×10²¹ protons-on-target. Meanwhile, NOνA experiment plan to expend the run up to 2024 for accumulating totally an amount of72×10²⁰protons-on-target. By combining T2K-II and NOνA with an ultimate constraint from reactor, the sensitivity to CP-violation is expected to exceed 4σ C.L. It is also pointed out that by reducing the systematic uncertainties of both T2K-II and NOνA to a level of 2 %, the sensitivity to CP-violation will significantly increase with a discovery possibility at 5σ C.L. significance for a particular range of true δCP. (author)

[en] A procedure of testing the f(R)-theory of gravity is discussed. The latter is an extension of the general theory of relativity (GR). In order this extended theory (in some variant) to be really confirmed as a more precise theory it must be tested. To do that we first have to solve an equation generalizing Einstein’s equation in the GR. However, solving this generalized Einstein’sequation is often very hard, even it is impossible in general to find an exact solution. It is why the perturbation method for solving this equation is used. In a recent work [1] a perturbation method was applied to the f(R)-theory of gravity in a central gravitational field which is a good approx-imation in many circumstances. There, perturbative solutions were found for a general form and some special forms of f(R). These solutions may allow us to test an f(R)-theory of gravity by calculating some quantities which can be verified later by the experiment (observation). In [1]an illustration was made on the case f(R) =R+λR². For this case, in the present article, theorbital precession of S2 orbiting around Sgr A* is calculated in a higher-order of approximation.The f(R)-theory of gravity should be also tested for other variants of f(R)not considered yetin [1]. Here, several representative variants are considered and in each case the orbital preces-sion is calculated for the Sun–Mercury- and the Sgr A*–S2 gravitational systems so that it can be compared with the value observed by a (future) experiment. Following the same method of [1] alight bending angle for an f(R)model in a central gravitational field can be also calculated andit could be a useful exercise. (author)

[en] In this paper, we describes different methods to immobilize Japanese encephalitis virus (JEV) antibodies in human serum onto the interdigitated surface of a microelectrode sensor for optimizing electrochemical detection: (1) direct covalent binding to the silanized surface, (2) binding to the silanized surface via a cross-linker of glutaraldehyde (GA), (3) binding to glutaraldehyde/silanized surface via goat anti-human IgG polyclonal antibody and (4) binding to glutaraldehyde/silanized surface via protein A (PrA). Field emission scanning electron microscopy, Fourier transform infrared spectrometry, and fluorescence microscopy are used to verify the characteristics of antibodies on the interdigitated surface after the serum antibodies immobilization. The analyzed results indicate that the use of protein A is an effective choice for immobilization and orientation of antibodies in serum for electrochemical biosensors. This study provides an advantageous immobilization method of serum containing antiviral antibodies to develop electrochemical biosensors for preliminary screening of viruses in clinical samples from outbreaks.

[en] It is shown that an effective (nonrenormalizable) coupling of lepton multiplets to scalar triplets in the 331 model with sterile/exotic neutrinos, can be a good way for generating neutrino masses of different types. The method is simple and avoids radiative/loop calculations which, sometimes, are long and complicated. Basing on some astrophysical arguments it is also stated that the scale of SU(3)_L symmetry breaking is at TeV scale, in agreement with earlier investigations. Or equivalently, starting from this symmetry breaking scale we could have sterile/exotic neutrinos with mass of a few keV's which could be used to explain several astrophysical and cosmological puzzles, such as the dark matter, the fast motion of the observed pulsars, the re-ionization of the Universe, etc