Sofia University

About: Sofia University is a education organization based out in Sofia, Bulgaria. It is known for research contribution in the topics: Large Hadron Collider & Laser. The organization has 8533 authors who have published 15730 publications receiving 306320 citations. The organization is also known as: University of Sofia & BFUS.

On the nonlinear schrödinger equation

Abstract: The nonlinear Schrodinger equation, iut + a∆u + q(|u| )u = 0, where a is a real constant, q is a real-valued function, and ∆ is the Laplacian operator, has been a topic of intensive research in the past 30 years. Recently, there is a growing interest in a fully nonlinear Schrodinger equation, iut + a∆u + q(|u| )u = b(∆p(|u|))p(|u|)u, where b is a real constant and p is a real-valued function, that arises in various physical models. This talk will give some current development for this equation.

Role of surfactant type and concentration for the mean drop size during emulsification in turbulent flow.

Abstract: A systematic experimental study of the effect of several factors on the mean drop diameter, d32, during emulsification, is performed with soybean oil-in-water emulsions. These factors are (1) type of used emulsifier; (2) emulsifier concentration, CS; and (3) ionic strength of the aqueous solution. Three different types of emulsifier, anionic (sodium dodecyl sulfate, SDS), nonionic (polyoxyethylene-20 cetyl ether, Brij 58), and protein (whey protein concentrate), are studied. For all of the studied systems, two well-defined regions are observed in the dependence of d32 on CS: at low surfactant concentration, d32 increases significantly with the decrease of CS (region 1), whereas d32 does not depend on CS at high surfactant concentration (region 2). The model, proposed by Tcholakova et al. (Langmuir 2003, 19, 5640), is found to describe well the dependence of d32 on CS in region 1 for the nonionic surfactant and for the protein emulsifier at high electrolyte concentration, 150 mM NaCl. According to this mo...

Search for a Higgs boson in the mass range from 145 to 1000 GeV decaying to a pair of W or Z bosons

Abstract: A search for a heavy Higgs boson in the H to WW and H to ZZ decay channels is reported. The search is based upon proton-proton collision data samples corresponding to an integrated luminosity of up to 5.1 inverse femtobarns at sqrt(s)=7 TeV and up to 19.7 inverse femtobarns at sqrt(s)=8 TeV, recorded by the CMS experiment at the CERN LHC. Several final states of the H to WW and H to ZZ decays are analyzed. The combined upper limit at the 95% confidence level on the product of the cross section and branching fraction exclude a Higgs boson with standard model-like couplings and decays in the range 145 < m[H] < 1000 GeV. We also interpret the results in the context of an electroweak singlet extension of the standard model.

Energy calibration and resolution of the CMS electromagnetic calorimeter in pp collisions at √s = 7 TeV

Abstract: The article is the pre-print version of the final publishing paper that is available from the link below.