3,144 research outputs found

    Was the Higgs boson discovered?

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    The standard model has postulated the existence of a scalar boson, named the Higgs boson. This boson plays a central role in a symmetry breaking scheme called the Brout-Englert-Higgs mechanism (or the Brout-Englert-Higgs-Guralnik-Hagen-Kibble mechanism, for completeness) making the standard model realistic. However, until recently at least, the 50-year-long-sought Higgs boson had remained the only particle in the standard model not yet discovered experimentally. It is the last but very important missing ingredient of the standard model. Therefore, searching for the Higgs boson is a crucial task and an important mission of particle physics. For this purpose, many theoretical works have been done and different experiments have been organized. It may be said in particular that to search for the Higgs boson has been one of the ultimate goals of building and running the LHC, the world's largest and most powerful particle accelerator, at CERN, which is a great combination of science and technology. Recently, in the summer of 2012, ATLAS and CMS, the two biggest and general-purpose LHC collaborations, announced the discovery of a new boson with a mass around 125 GeV. Since then, for over two years, ATLAS, CMS and other collaborations have carried out intensive investigations on the newly discovered boson to confirm that this new boson is really the Higgs boson (of the standard model). It is a triumph of science and technology and international cooperation. Here, we will review the main results of these investigations following a brief introduction to the Higgs boson within the theoretical framework of the standard model and Brout-Englert-Higgs mechanism as well as a theoretical and experimental background of its search. This paper may attract interest of not only particle physicists but also a broader audience.Comment: LateX, 23 pages, 01 table, 9 figures. To appear in Commun. Phys. Version 2: Minor changes, two references adde

    A Complete Solver for Constraint Games

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    Game Theory studies situations in which multiple agents having conflicting objectives have to reach a collective decision. The question of a compact representation language for agents utility function is of crucial importance since the classical representation of a nn-players game is given by a nn-dimensional matrix of exponential size for each player. In this paper we use the framework of Constraint Games in which CSP are used to represent utilities. Constraint Programming --including global constraints-- allows to easily give a compact and elegant model to many useful games. Constraint Games come in two flavors: Constraint Satisfaction Games and Constraint Optimization Games, the first one using satisfaction to define boolean utilities. In addition to multimatrix games, it is also possible to model more complex games where hard constraints forbid certain situations. In this paper we study complete search techniques and show that our solver using the compact representation of Constraint Games is faster than the classical game solver Gambit by one to two orders of magnitude.Comment: 17 page

    Investigation of Reactions between Glauconite and Carbon Dioxide, with Implications for Carbon Sequestration

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    The objective of this study was to develop a protocol to test the reactivity of glauconite, a Fe/Mg bearing aluminosilicate mineral, in carbon storage. A selected glauconite-rich sample from the Cambrian Riley Formation of Central Texas was used containing glauconite 38 wt%, quartz 58 wt%, and calcite 4 wt%. Ten experiments were conducted using two techniques where total pressure was: 1) controlled by delivering CO2 to a high-pressure apparatus; 2) kept at saturated vapor level in autoclaves. The treated glauconite samples were analyzed with Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (SEM), and X-ray Diffraction techniques (XRD). Although the reaction between glauconite and CO2 was not visible, calcite crystallized in solution when its pH exceeded the value of 6.88. The research provides a foundation to develop further investigations of rock reactions under CO2 saturated conditions
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