Bulgarian Academy of Sciences

About: Bulgarian Academy of Sciences is a government organization based out in Sofia, Bulgaria. It is known for research contribution in the topics: Catalysis & Coupling constant. The organization has 17989 authors who have published 36276 publications receiving 642820 citations. The organization is also known as: Bulgarian Academy of Sciences，簡稱：BAS & Balgarska Akademiya na Naukite.

Measurements of W ± Z production cross sections in pp collisions at √s = 8 TeV with the ATLAS detector and limits on anomalous gauge boson self-couplings

Abstract: This paper presents measurements of W(+/-)Z production in pp collisions at a center-of-mass energy of 8 TeV. The gauge bosons are reconstructed using their leptonic decay modes into electrons and m ...

Search for Resonant Production of High-Mass Photon Pairs in Proton-Proton Collisions at s =8 and 13 TeV

Abstract: A search for the resonant production of high-mass photon pairs is presented. The analysis is based on samples of proton-proton collision data collected by the CMS experiment at center-of-mass energies of 8 and 13 TeV, corresponding to integrated luminosities of 19.7 and 3.3 fb(-1), respectively. The interpretation of the search results focuses on spin-0 and spin-2 resonances with masses between 0.5 and 4 TeV and with widths, relative to the mass, between 1.4 x 10(-4) and 5.6 x 10(-2). Limits are set on scalar resonances produced through gluon-gluon fusion, and on Randall-Sundrum gravitons. A modest excess of events compatible with a narrow resonance with a mass of about 750 GeV is observed. The local significance of the excess is approximately 3.4 standard deviations. The significance is reduced to 1.6 standard deviations once the effect of searching under multiple signal hypotheses is considered. More data are required to determine the origin of this excess.

Finite element modeling of the morphology of β to α phase transformation in Ti-6Al-4V alloy

Abstract: In the present work, a mathematical model and computer programs were developed for numerical simulation of the processes of nucleation and growth of the α-phase Widmanstatten plates during the course of the β ⇒ α phase transformation in a Ti-6Al-4V alloy. The α-phase appearance at the grain boundary of β phase is described by a numerical procedure for random nucleation as a function of the vanadium concentration and the temperature. The rate at which an interface moves depends both on the intrinsic mobility and on the rate at which diffusion can remove the excess of vanadium atoms ahead of the interface. The finite-element method (FEM) was used for solving the diffusion equation on the domain occupied by β phase. The elements chosen have dimensions in both space and time. A computer code based on the finite-element modeling and the volume of fluids method was developed to trace the movement of the α/β interface. The influences of the cooling rate and the temperature of isothermal exposure on the Widmanstatten morphology were simulated and analyzed. The developed models and program packages are capable of one-dimensional (1-D) and two-dimensional (2-D) simulations of the morphology of the β ⇒ α phase transformation in Ti-6Al-4V alloy for continuous cooling with any cooling path and for an arbitrary combination between continuous cooling and isothermal exposure.