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 $n$-players game is given by a $n$-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

Effects of Food Safety Standards on Seafood Exports to US, EU and Japan

Estimating the panel gravity model with bilateral pair and country-by-time fixed-effects separately for each seafood product, we found that food safety regulations have differential effects across seafood products. In all three industrialized markets, shrimp is most sensitive, while fish is the least sensitive to changing food safety policies. The enforcement of the US HACCP, the EU Minimum Required Performance Level and the Japanese Food Safety Basic Law caused a loss of 90.45%, 99.47%, and 99.97% to shrimp trade in these markets, and a reduction associated with fish trade was 66.71%, 82.83%, and 89.32%.food safety, seafood, international trade, gravity model, HACCP, Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety, International Relations/Trade, C33, F13, Q17, Q18,

A Backward Algorithm for the Multiprocessor Online Feasibility of Sporadic Tasks

The online feasibility problem (for a set of sporadic tasks) asks whether there is a scheduler that always prevents deadline misses (if any), whatever the sequence of job releases, which is a priori} unknown to the scheduler. In the multiprocessor setting, this problem is notoriously difficult. The only exact test for this problem has been proposed by Bonifaci and Marchetti-Spaccamela: it consists in modelling all the possible behaviours of the scheduler and of the tasks as a graph; and to interpret this graph as a game between the tasks and the scheduler, which are seen as antagonistic players. Then, computing a correct scheduler is equivalent to finding a winning strategy for the `scheduler player', whose objective in the game is to avoid deadline misses. In practice, however this approach is limited by the intractable size of the graph. In this work, we consider the classical attractor algorithm to solve such games, and introduce antichain techniques to optimise its performance in practice and overcome the huge size of the game graph. These techniques are inspired from results from the formal methods community, and exploit the specific structure of the feasibility problem. We demonstrate empirically that our approach allows to dramatically improve the performance of the game solving algorithm.Comment: Long version of a conference paper accepted to ACSD 201

Characterization of diverse soybean genotypes for phosphorus uptake and use efficiency

Soybean (Glycine max L. Merrill) is one of the most important legume crops grown worldwide. However, without phosphorus (P) fertilization, soybean yields often are limited by phosphorus availability. Phosphorus is an essential macronutrient and P uptake ability and P use efficiency (PUE) of a crop critically influence its productivity. To improve soybean yields under low-P conditions, a better understanding of the mechanisms underlying P uptake and PUE is needed. The first part of this study was aimed at identifying and characterizing soybean genotypes which contrast in their ability to take up P and in their PUE. Results from pot and field experiments with diverse soybean genotypes, including SoyNAM parents, obsolete cultivars, commercial cultivars, and plant introduction lines, revealed significant differences among genotypes for numerous P-related traits. Significant differences in shoot P concentration, shoot P content used as surrogate measure for P uptake, physiological PUE, and root complexity were observed among genotypes. Phosphorus use efficiency was much higher under low-P conditions compared to P-sufficient conditions. Positive correlations between biomass production and P uptake and top-soil root architecture and P uptake were observed. In a subset of five contrasting genotypes, soybean root symbiosis with arbuscular mycorrhizal fungi (AMF) was investigated to explore whether mycorrhizal infection levels were related with genotype differences in P uptake and PUE. All five genotypes displayed high AMF colonization percentages ([greater than] 80 percent) and no significant differences in mycorrhizal colonization were detected among genotypes and between low-P and P sufficient treatments. Arbuscular mycorrhizal fungi colonization did not explain observed differences in P uptake, and approaches aimed at increasing levels of AMF infection in soybean do not appear promising, at least not for environments like the one used in this study. This research identified soybean genotypes contrasting for shoot P concentration, shoot P content, PUE, and topsoil root system architecture. Further, it confirmed differential sensitivity of diverse soybean genotypes to P availability. The identified genotypes can serve as a resource for physiological and genetic studies as well as in breeding efforts aimed at improving P uptake and PUE in elite germplasm.Includes bibliographical references