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The European Organization for Nuclear Research , known as CERN is a European research organization that operates the largest particle physics laboratory in the world. Established in 1954, the organization is based in the northwest suburbs of Geneva on the Franco–Swiss border, and has 21 European member states. Israel is the first non-European country granted full membership.The term CERN is also used to refer to the laboratory, which in 2013 counted 2,513 staff members, and hosted some 12,313 fellows, associates, apprentices as well as visiting scientists and engineers representing 608 universities and research facilities and 113 nationalities.CERN's main function is to provide the particle accelerators and other infrastructure needed for high-energy physics research – as a result, numerous experiments have been constructed at CERN following international collaborations.CERN is also the birthplace of the World Wide Web. The main site at Meyrin has a large computer centre containing powerful data processing facilities, primarily for experimental-data analysis; because of the need to make these facilities available to researchers elsewhere, it has historically been a major wide area networking hub. Wikipedia.


Altarelli G.,Third University of Rome | Altarelli G.,CERN | Feruglio F.,University of Padua
Reviews of Modern Physics | Year: 2010

Application of non-Abelian finite groups to the theory of neutrino masses and mixing is reviewed, which is strongly suggested by the agreement of the tribimaximal (TB) mixing pattern with experiment. After summarizing the motivation and the formalism, concrete models based on A4, S 4, and other finite groups, and their phenomenological implications are discussed, including lepton flavor violating processes, leptogenesis, and the extension to quarks. As an alternative to TB mixing application of discrete flavor symmetries to quark-lepton complementarity and bimaximal mixing is also considered. © 2010 The American Physical Society.


Bird I.,CERN
Annual Review of Nuclear and Particle Science | Year: 2011

Following the first full year of Large Hadron Collider (LHC) data taking, the Worldwide LHC Computing Grid (WLCG) computing environment built to support LHC data processing and analysis has been validated. In this review, I discuss the rationale for the design of a distributed system and describe how this environment was constructed and deployed through the use of grid computing technologies. I discuss the experience with large-scale testing and operation with real accelerator data, which shows that expectations have been met and sometimes exceeded. The computing system's key achievements are that (a) the WLCG infrastructure is distributed and makes use of all the dispersed resources, (b) the experiments' computing models are also distributed and can make excellent use of the infrastructure, and (c) the computing system has enabled physics output in a very short time. Finally, I present prospects for the future evolution of the WLCG infrastructure. © 2011 by Annual Reviews. All rights reserved.


We present the complete next-to-leading-order (NLO) contributions to the pp→e+νeμ-ν̄μbb̄+X process in the four-flavor scheme, i.e., with massive b quarks, and its contribution to the H→WW(*) →llνν measurement in the 1-jet bin at the LHC. This background process includes top pair, single top, and non-top-quark resonant contributions. The uncertainty at NLO from the renormalization and factorization scale dependence is about +30%-20%. We show that the NLO corrections are relatively small, and that separating this background in top pair, Wt- and b-quark-associated llνν production is a fair approximation. © 2014 American Physical Society.


Patella A.,CERN
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

A strategy for computing the ψ̄ψ anomalous dimension at the fixed point in infrared-conformal gauge theories from lattice simulations is discussed. The method is based on the scaling of the spectral density of the Dirac operator or rather its integral, the mode number. It is relatively cheap, mainly for two reasons: (a) the mode number can be determined with quite high accuracy, and (b) the ψ̄ψ anomalous dimension is extracted from a fit of several observables on the same set of configurations (no scaling in the Lagrangian parameters is needed). As an example the ψ̄ψ anomalous dimension has been computed in the SU(2) theory with 2 Dirac fermions in the adjoint representation of the gauge group and has been found to be γ *=0.371(20). In this particular case, the proposed strategy has proved to be very robust and effective. © 2012 American Physical Society.


Papaefstathiou A.,CERN
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

We consider the process of Higgs boson pair production at a future proton collider with a center-of-mass energy of 100 TeV, focusing on rare final states that include a bottom-antibottom quark pair and multiple isolated leptons: hh→(bb¯)+n+X, n={2,4}, X={ET,γ,-}. We construct experimental search strategies for observing the process through these channels and make suggestions on the desired requirements for the detector design of the future collider. © Published by the American Physical Society.

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