Institution
Sofia University
Education•Sofia, Bulgaria•
About: Sofia University is a education organization based out in Sofia, Bulgaria. It is known for research contribution in the topics: Large Hadron Collider & Standard Model. The organization has 8533 authors who have published 15730 publications receiving 306320 citations. The organization is also known as: University of Sofia & BFUS.
Topics: Large Hadron Collider, Standard Model, Population, Lepton, Laser
Papers published on a yearly basis
Papers
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TL;DR: In this article, the polarized Raman spectra of CTO single crystals were studied between 10 and 600 K and the assignment of the Raman lines to modes of definite symmetry and eigenvector was done in close comparison with results of lattice dynamics calculations.
Abstract: The polarized Raman spectra of ${\mathrm{CaCu}}_{3}{\mathrm{Ti}}_{4}{\mathrm{O}}_{12}$ (CCTO) single crystals were studied between 10 and 600 K. Five of the eight ${(2A}_{g}{+2E}_{g}{+4F}_{g})$ Raman active modes expected for the $\mathrm{Im}3\ifmmode\bar\else\textasciimacron\fi{}$ structure were observed at $292{(F}_{g}),$ ${445(A}_{g}),$ ${499(E}_{g}),$ ${511(A}_{g}),$ and ${575(F}_{g}){\mathrm{cm}}^{\ensuremath{-}1}.$ The assignment of the Raman lines to modes of definite symmetry and eigenvector was done in close comparison with results of lattice dynamics calculations. The mode frequency vs temperature dependence exhibits no anomalies in the whole temperature range. This is consistent with earlier indications that the high value of the dielectric constants and its strong decrease below 100 K are not related to temperature-dependent atomic displacements. An additional line of ${A}_{g}$ symmetry, clearly seen at low temperatures is tentatively assigned to vibrations of distorted ${\mathrm{TiO}}_{6}$ octahedra, presumably at twin boundaries.
135 citations
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University of Geneva1, University of Warsaw2, National and Kapodistrian University of Athens3, Saint Petersburg State University4, Joint Institute for Nuclear Research5, Karlsruhe Institute of Technology6, Warsaw University of Technology7, Hungarian Academy of Sciences8, Federico Santa María Technical University9, Jagiellonian University10, University of Silesia in Katowice11, Pusan National University12, Stony Brook University13, ETH Zurich14, University of Bern15, Eötvös Loránd University16, Jan Kochanowski University17, Frankfurt University of Applied Sciences18, University of Wrocław19, Sofia University20, Goethe University Frankfurt21, University of Bergen22
TL;DR: In this article, the neutrino interaction cross sections and charged pion spectra were measured with the large-acceptance NA61/SHINE spectrometer at the CERN SPS.
Abstract: Interaction cross sections and charged pion spectra in p+C interactions at 31 GeV/c were measured with the large-acceptance NA61/SHINE spectrometer at the CERN SPS. These data are required to improve predictions of the neutrino flux for the T2K long-baseline neutrino oscillation experiment in Japan. A set of data collected during the first NA61/SHINE run in 2007 with an isotropic graphite target with a thickness of 4% of a nuclear interaction length was used for the analysis. The measured p+C inelastic and production cross sections are 257.2 {+-} 1.9 {+-} 8.9 and 229.3 {+-} 1.9 {+-} 9.0 mb, respectively. Inclusive production cross sections for negatively and positively charged pions are presented as functions of laboratory momentum in ten intervals of the laboratory polar angle covering the range from 0 up to 420 mrad. The spectra are compared with predictions of several hadron production models.
135 citations
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TL;DR: In this paper, a simple cell model is proposed to calculate the disjoining pressure contribution due to the presence of micellar structure inside the thinning liquid films, and the calculated excess energy per unit area of the film exhibits a number of minima corresponding to the metastable states with mousellar layers inside the film.
135 citations
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TL;DR: The technical and theoretical basis of newly developed instruments, allowing for simultaneous measurement of the PF and the DF as well as other parameters is discussed, and special emphasis has been given to a description of comparative measurements on PF and DF.
Abstract: This review is dedicated to David Walker (1928–2012), a pioneer in the field of photosynthesis and chlorophyll fluorescence. We begin this review by presenting the history of light emission studies, from the ancient times. Light emission from plants is of several kinds: prompt fluorescence (PF), delayed fluorescence (DF), thermoluminescence, and phosphorescence. In this article, we focus on PF and DF. Chlorophyll a fluorescence measurements have been used for more than 80 years to study photosynthesis, particularly photosystem II (PSII) since 1961. This technique has become a regular trusted probe in agricultural and biological research. Many measured and calculated parameters are good biomarkers or indicators of plant tolerance to different abiotic and biotic stressors. This would never have been possible without the rapid development of new fluorometers. To date, most of these instruments are based mainly on two different operational principles for measuring variable chlorophyll a fluorescence: (1) a PF signal produced following a pulse-amplitude-modulated excitation and (2) a PF signal emitted during a strong continuous actinic excitation. In addition to fluorometers, other instruments have been developed to measure additional signals, such as DF, originating from PSII, and light-induced absorbance changes due to the photooxidation of P700, from PSI, measured as the absorption decrease (photobleaching) at about 705 nm, or increase at 820 nm. In this review, the technical and theoretical basis of newly developed instruments, allowing for simultaneous measurement of the PF and the DF as well as other parameters is discussed. Special emphasis has been given to a description of comparative measurements on PF and DF. However, DF has been discussed in greater details, since it is much less used and less known than PF, but has a great potential to provide useful qualitative new information on the back reactions of PSII electron transfer. A review concerning the history of fluorometers is also presented.
135 citations
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TL;DR: In this article, a search for physics beyond the standard model in events with at least three leptons is presented, and limits are placed on new-physics scenarios that yield multilepton final states.
Abstract: A search for physics beyond the standard model in events with at least three leptons is presented. The data sample, corresponding to an integrated luminosity of 19.5 fb^(−1) of proton-proton collisions with center-of-mass energy √s=8 TeV, was collected by the CMS experiment at the LHC during 2012. The data are divided into exclusive categories based on the number of leptons and their flavor, the presence or absence of an opposite-sign, same-flavor lepton pair (OSSF), the invariant mass of the OSSF pair, the presence or absence of a tagged bottom-quark jet, the number of identified hadronically decaying τ leptons, and the magnitude of the missing transverse energy and of the scalar sum of jet transverse momenta. The numbers of observed events are found to be consistent with the expected numbers from standard model processes, and limits are placed on new-physics scenarios that yield multilepton final states. In particular, scenarios that predict Higgs boson production in the context of supersymmetric decay chains are examined. We also place a 95% confidence level upper limit of 1.3% on the branching fraction for the decay of a top quark to a charm quark and a Higgs boson (t→cH), which translates to a bound on the left- and right-handed top-charm flavor-violating Higgs Yukawa couplings, λ^H_(tc) and λ^H_(ct), respectively, of √|λ^H_(tc)|^2+|λ^H_(ct)|^2<0.21.
134 citations
Authors
Showing all 8600 results
Name | H-index | Papers | Citations |
---|---|---|---|
Michael Tytgat | 134 | 1449 | 94133 |
Leander Litov | 133 | 1424 | 92713 |
Eric Conte | 132 | 1206 | 84593 |
Georgi Sultanov | 132 | 1493 | 93318 |
Plamen Iaydjiev | 131 | 1285 | 87958 |
Anton Dimitrov | 130 | 1236 | 86919 |
Jordan Damgov | 129 | 1195 | 85490 |
Borislav Pavlov | 129 | 1245 | 86458 |
Jean-Laurent Agram | 128 | 1221 | 84423 |
Cristina Botta | 128 | 1160 | 79070 |
Jean-Charles Fontaine | 128 | 1190 | 84011 |
Peicho Petkov | 128 | 1111 | 83495 |
Muhammad Ahmad | 128 | 1187 | 79758 |
Roumyana Hadjiiska | 126 | 1003 | 73091 |
Mircho Rodozov | 124 | 972 | 70519 |