Institution
Bulgarian Academy of Sciences
Government•Sofia, Bulgaria•
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.
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05 Mar 2014
TL;DR: In this article, double parton scattering was investigated in proton-proton collisions at 7 TeV where the final state includes a W boson which decays into a muon and a neutrino, and two jets.
Abstract: Double parton scattering is investigated in proton-proton collisions at sqrt(s) = 7 TeV where the final state includes a W boson, which decays into a muon and a neutrino, and two jets. The data sample corresponds to an integrated luminosity of 5 inverse femtobarns, collected with the CMS detector at the LHC. Observables sensitive to double parton scattering are investigated after being corrected for detector effects and selection efficiencies. The fraction of W + 2-jet events due to double parton scattering is measured to be 0.055 +/- 0.002 (stat.) +/- 0.014 (syst.). The effective cross section, sigma[eff], characterizing the effective transverse area of hard partonic interactions in collisions between protons is measured to be 20.7 +/- 0.8 (stat.) +/- 6.6 (syst.) mb.
128 citations
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INAF1, Spanish National Research Council2, University of La Laguna3, Pulkovo Observatory4, Bulgarian Academy of Sciences5, National Autonomous University of Mexico6, Sofia University7, Max Planck Society8, University of Southampton9, National Central University10, University of Bologna11, Saint Petersburg State University12, Harvard University13, Liverpool John Moores University14, Dublin Institute for Advanced Studies15, Boston University16, Fesenkov Astrophysical Institute17, Al-Farabi University18, Aalto University19, Tartu Observatory20, Osaka Kyoiku University21, University College Dublin22, Brigham Young University23, Technische Hochschule Mittelhessen24, University of Colorado Denver25, Lowell Observatory26, University of Arizona27
TL;DR: It is shown that the observed long-term trends of the flux and spectral variability are best explained by an inhomogeneous, curved jet that undergoes changes in orientation over time, and proposes that magnetohydrodynamic instabilities or rotation of the twisted jet cause different jet regions to change their orientation and hence their relative Doppler factors.
Abstract: Blazars are active galactic nuclei, which are powerful sources of radiation whose central engine is located in the core of the host galaxy. Blazar emission is dominated by non-thermal radiation from a jet that moves relativistically towards us, and therefore undergoes Doppler beaming. This beaming causes flux enhancement and contraction of the variability timescales, so that most blazars appear as luminous sources characterized by noticeable and fast changes in brightness at all frequencies. The mechanism that produces this unpredictable variability is under debate, but proposed mechanisms include injection, acceleration and cooling of particles, with possible intervention of shock waves or turbulence. Changes in the viewing angle of the observed emitting knots or jet regions have also been suggested as an explanation of flaring events and can also explain specific properties of blazar emission, such as intra-day variability, quasi-periodicity and the delay of radio flux variations relative to optical changes. Such a geometric interpretation, however, is not universally accepted because alternative explanations based on changes in physical conditions-such as the size and speed of the emitting zone, the magnetic field, the number of emitting particles and their energy distribution-can explain snapshots of the spectral behaviour of blazars in many cases. Here we report the results of optical-to-radio-wavelength monitoring of the blazar CTA 102 and show that the observed long-term trends of the flux and spectral variability are best explained by an inhomogeneous, curved jet that undergoes changes in orientation over time. We propose that magnetohydrodynamic instabilities or rotation of the twisted jet cause different jet regions to change their orientation and hence their relative Doppler factors. In particular, the extreme optical outburst of 2016-2017 (brightness increase of six magnitudes) occurred when the corresponding emitting region had a small viewing angle. The agreement between observations and theoretical predictions can be seen as further validation of the relativistic beaming theory.
128 citations
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TL;DR: The results indicate an increased supramolecular structural stability in the presence of glycinebetaine, which protected the D1/D2/Cytb559 complexes against strong light-induced damage to the photochemical reactions and the irreversible bleaching of beta-carotene and chlorophyll.
128 citations
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TL;DR: In this paper, LiMnyCo1−yO2 has been obtained by a solid state reaction between lithium hydroxide and manganese-cobalt spinels in air (0.1−4.2 V) or under nitrogen ( 0.2 < y<1).
128 citations
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TL;DR: In this article, a peaking structure in the J/psi phi mass spectrum near threshold was observed in B(+/-) to J/Psi K(−)-decays, produced in pp collisions at sqrt(s) = 7 TeV collected with the CMS detector at the LHC.
128 citations
Authors
Showing all 18074 results
Name | H-index | Papers | Citations |
---|---|---|---|
Dimitri Bourilkov | 134 | 1489 | 96884 |
Eduardo De Moraes Gregores | 133 | 1454 | 92464 |
Georgi Sultanov | 132 | 1493 | 93318 |
Plamen Iaydjiev | 131 | 1285 | 87958 |
Pedro G Mercadante | 129 | 1331 | 86378 |
Jordan Damgov | 129 | 1195 | 85490 |
Roumyana Hadjiiska | 126 | 1003 | 73091 |
Mircho Rodozov | 124 | 972 | 70519 |
Cesar Augusto Bernardes | 124 | 965 | 70889 |
Viktor Matveev | 123 | 1212 | 73939 |
Ayda Beddall | 120 | 816 | 67063 |
Andrey Marinov | 119 | 893 | 57183 |
Mariana Vutova | 117 | 606 | 56698 |
Lester Packer | 112 | 751 | 63116 |
Patrick Couvreur | 111 | 678 | 56735 |