3,146 research outputs found
Was the Higgs boson discovered?
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
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 -players game is given by a
-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
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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