Heavy feet for the LHC

CERN Document Server

2003-01-01

The first 800 jacks (adjustable supports) for one sector of the LHC have arrived from India in recent weeks. After the final acceptance of the preseries jacks at the end of October, they can now be used to support the LHC cryo-magnets. How do you move the weight of eight adult Indian elephants by the breadth of a human hair? If you are a surveyor at CERN who has to adjust the 32 ton LHC dipoles with a resolution of 1/20 of a millimetre, you use the 80 kg jacks which were designed and are being procured by the Centre for Advanced Technology (CAT) in India. The jacks are undergoing final pre-shipment inspection by CAT engineers in India. More than 800 jacks have arrived in recent weeks from India, enough to equip the first sector of the LHC (one octant of the ring). For all the cryo-magnets (dipoles and quadrupoles) of the LHC 7000 jacks are needed in total. They are now being continuously delivered to CERN up to mid-2005. The close collaboration between the Department of Atomic Energy (DAE) in India and CE...

How to implement all HL-LHC upgrades

CERN Document Server

Rossi, L; Ballarino, A; Brüning, O; Jensen, E; Redaelli, S; Tavian, L; Todesco, E

2014-01-01

The luminosity upgrade will require major changes in the LHC machine layout : about 1.2 km of the machine will undergo major renova tion or modification. In the paper we will review the list of main equipment foreseen to be replaced or to be added. We will review the upgrade plan that should start already in the Long Shutdown (LS) 2 (with the installation of the first dispersion suppressor 11T dipole – collimator unit , the superconducting link in Point 7 and the cryo-plant in Point 4), through to the major works in LS3, synchronized with an upgrade of the LHC detectors. Best estimates of the required duration of the various shutdowns will be discussed, and also the main risks and their mitigation.

Impedance measurements and simulations for the LHC and HL-LHC injection protection collimator

CERN Document Server

AUTHOR|(CDS)2125995; Biancacci, Nicolò

This thesis focuses on the study and the data analysis of the Injection Protection Collimator (also Injection Protection Target Dump or TDI), one of the Large Hadron Collider (LHC) collimators at CERN, in Geneva. The last chapters also deal with the Segmented TDI (TDIS), the TDI upgrade for High Luminosity-LHC (HL-LHC). Going more into details, measurements on the TDI - hexagonal Boron Nitride (TDI - hBN, installed in the LHC during run 2015) were carried out. Using the obtained results as an input, two derivations followed: one evaluating the layer resistivity and the other one for its thickness, in order to consider all the possible coating degradations that could occur. The whole range of data obtained from both the derivations was then fed to Impedance Wake 2D (IW2D), a code performing numerical simulations, to attain impedances. Finally, the resulting longitudinal impedance was compared to some measurements performed on the real TDIs, immediately after they were removed from the LHC. The TDI - Graphite, ...

High Luminosity LHC Project Description

CERN Document Server

Apollinari, Giorgio; Rossi, Lucio

2014-01-01

The High Luminosity LHC (HL-LHC) is a novel configuration of the Large Hadron Collider, aiming at increasing the luminosity by a factor five or more above the nominal LHC design, to allow increasing the integrated luminosity, in the high luminosity experiments ATLAS and CMS, from the 300 fb-1 of the LHC original design up to 3000 fb-1 or more. This paper contains a short description of the main machine parameters and of the main equipment that need to be developed and installed. The preliminary cost evaluation and the time plan are presented, too. Finally, the international collaboration that is supporting the project, the governance and the project structure are discussed, too.

Optics Designs of Final-Focus Systems for Future LHC Upgrades

CERN Document Server

Abelleira, J L; Zimmermann, Frank; Rivkin, Leonid

2014-01-01

The main topic of the thesis is the study of a novel option for the high-luminosity upgrade of the Large Hadron Collider (LHC) comprising a large Piwinski angle, flat beams, and crab waists. Flat beams and crab waists are not only pre-requisites for a crab-waist scheme, but, even by themselves; each of these two elements alone could boost the luminosity of the existing collider as built. The new optics involves an upgrade of the interaction region of the two high-luminosity experiments, ATLAS and CMS, in order to provide them with a substantially higher luminosity. To this end, a flat-beam optics scenario has been explored for the High Luminosity LHC (HL-LHC), with a much reduced vertical beta function at the interaction point (IP), $\\beta_y^*$. In addition, a large Piwinski angle is considered. Advantages of a large Piwinski angle include a reduction in the hourglass effect over the length of the collision area, which allows for the significant $\\beta_y^*$ decrease. In addition there is a reduction of the be...

View of the LHC tunnel with worker.

CERN Multimedia

Maximilien Brice

2006-01-01

The 616th dipole out of 1232, on its way to its final position in the tunnel of the LHC. Technicians and engineers continue to work day and night carefully installing 20 magnets a week. Each of the dipoles weighs 34 tonnes and is 15 m long. Once they have been lowered down the specially constructed shaft on the Meyrin site, they begin a slow progression to their final destinations in the LHC tunnel, taking about 10 hours to arrive at Point 6, the furthest point on the LHC ring. Upon arrival, each of the dipoles is aligned and interconnected to the magnets that are already installed.Bigger files available (39Mpx)

New type of chaos synchronization in discrete-time systems: the F-M synchronization

Directory of Open Access Journals (Sweden)

Ouannas Adel

2018-04-01

Full Text Available In this paper, a new type of synchronization for chaotic (hyperchaotic maps with different dimensions is proposed. The novel scheme is called F – M synchronization, since it combines the inverse generalized synchronization (based on a functional relationship F with the matrix projective synchronization (based on a matrix M. In particular, the proposed approach enables F – M synchronization with index d to be achieved between n-dimensional drive system map and m-dimensional response system map, where the synchronization index d corresponds to the dimension of the synchronization error. The technique, which exploits nonlinear controllers and Lyapunov stability theory, proves to be effective in achieving the F – M synchronization not only when the synchronization index d equals n or m, but even if the synchronization index d is larger than the map dimensions n and m. Finally, simulation results are reported, with the aim to illustrate the capabilities of the novel scheme proposed herein.

New type of chaos synchronization in discrete-time systems: the F-M synchronization

Science.gov (United States)

Ouannas, Adel; Grassi, Giuseppe; Karouma, Abdulrahman; Ziar, Toufik; Wang, Xiong; Pham, Viet-Thanh

2018-04-01

In this paper, a new type of synchronization for chaotic (hyperchaotic) maps with different dimensions is proposed. The novel scheme is called F - M synchronization, since it combines the inverse generalized synchronization (based on a functional relationship F) with the matrix projective synchronization (based on a matrix M). In particular, the proposed approach enables F - M synchronization with index d to be achieved between n-dimensional drive system map and m-dimensional response system map, where the synchronization index d corresponds to the dimension of the synchronization error. The technique, which exploits nonlinear controllers and Lyapunov stability theory, proves to be effective in achieving the F - M synchronization not only when the synchronization index d equals n or m, but even if the synchronization index d is larger than the map dimensions n and m. Finally, simulation results are reported, with the aim to illustrate the capabilities of the novel scheme proposed herein.

Helium Inventory Management For LHC Cryogenics

CERN Document Server

Pyarali, Maisam

2017-01-01

The LHC is a 26.7 km circumference ring lined with superconducting magnets that operate at 1.9 K. These magnets are used to control the trajectory of beams of protons traveling in opposite directions and collide them at various experimental sites across the LHC where their debris is analyzed. The focus of this paper is the cryogenic system that allows the magnets to operate in their superconducting states. It aims to highlight the operating principles of helium refrigeration and liquefaction, with and without nitrogen pre-cooling; discuss the various refrigerators and liquefiers used at CERN for both LHC and Non-LHC applications, with their liquefaction capacities and purposes; and finally to deliberate the management of the LHC inventory and how it contributes to the strategic decision CERN makes regarding the inventory management during the Year-End Technical Stop (YETS), Extended Year-End Technical Stop (EYETS) and long shutdowns.

LHC Report: a brief deceleration

CERN Multimedia

Rossano Giachino & Markus Albert

2015-01-01

The LHC has now transitioned from powering tests to the machine checkout phase. This phase involves the full-scale tests of all systems in preparation for beam. Early last Saturday morning, during the ramp-down, an earth fault developed in the main dipole circuit. Full evaluation of the situation is ongoing.   The various systems are put through their operational paces from the CCC. This includes important tests of the beam dump system and full-scale tests of the beam interlock system (BIS) and its many inputs from other systems around the ring. All magnetic circuits are driven through the ramp, squeeze, ramp-down, and pre-cycle along with the collimators and RF. Instrumentation, feedbacks, and the control system are also stress tested. Inevitably there is some final frantic debugging but, up to now, things seem to be in reasonable shape. The machine checkout is an important coming together of all LHC systems. During this final phase before beam, the operations team tests all of the LHC subsystem...

A Fast CVD Diamond Beam Loss Monitor for LHC

CERN Document Server

Griesmayer, E; Dobos, D; Effinger, E; Pernegger, H

2011-01-01

Chemical Vapour Deposition (CVD) diamond detectors were installed in the collimation area of the CERN LHC to study their feasibility as Fast Beam Loss Monitors in a high-radiation environment. The detectors were configured with a fast, radiation-hard pre-amplifier with a bandwidth of 2 GHz. The readout was via an oscilloscope with a bandwidth of 1 GHz and a sampling rate of 5 GSPS. Despite the 250 m cable run from the detectors to the oscilloscope, single MIPs were resolved with a 2 ns rise time, a pulse width of 10 ns and a time resolution of less than 1 ns. Two modes of operation were applied. For the analysis of unexpected beam aborts, the loss profile was recorded in a 1 ms buffer and, for nominal operation, the histogram of the time structure of the losses was recorded in synchronism with the LHC period of 89.2 μs. Measurements during the LHC start-up (February to December 2010) are presented. The Diamond Monitors gave an unprecedented insight into the time structure of the beam losses resolving the 400...

STATISTICAL CHALLENGES FOR SEARCHES FOR NEW PHYSICS AT THE LHC.

Energy Technology Data Exchange (ETDEWEB)

CRANMER, K.

2005-09-12

Because the emphasis of the LHC is on 5{sigma} discoveries and the LHC environment induces high systematic errors, many of the common statistical procedures used in High Energy Physics are not adequate. I review the basic ingredients of LHC searches, the sources of systematics, and the performance of several methods. Finally, I indicate the methods that seem most promising for the LHC and areas that are in need of further study.

The LHC Project Status and Prospects

CERN Document Server

Faugeras, Paul E

2001-01-01

The Large Hadron Collider (LHC), CERN's future major facility for high-energy physics, has entered into the construction and preparation for installation phases. After recalling briefly the main machine design choices and challenges, one will review the progress of civil works for the machine and experimental areas and the status of the main LHC components, which are presently series-built and for some of them procured in kind through world-wide collaborations. Report will also be given on the full-scale prototype of an elementary LHC lattice cell, called String 2, which is being commissioned and used for optimising the installation and testing procedures of the LHC. The size and duration of the LHC Project, its intrinsic complexity and the large number of world-wide collaborations involved require rather elaborate project management tools, which will be shortly described. Finally, following the extended running of the LEP and the delay for emptying of the machine tunnel, a new planning for project completion...

Working on an LHC dipole end-cap

CERN Multimedia

Laurent Guiraud

1999-01-01

A metal worker constructs an end-cap for an LHC dipole magnet. These magnets will be used to bend the proton beams around the LHC, which is due to start up in 2008. The handmade prototype seen here will be used to make a mold from which the final set of components will be made for the accelerator.

A worker inside the LHC tunnel

CERN Multimedia

Maximilien Brice

2006-01-01

Technicians and engineers worked days and nights, carefully installing 20 magnets a week between 7 March 2005 and 26 April 2006. Each dipole weighs 34 tonnes and is 15 m long. Once they have been lowered down the specially constructed shaft, they begin a slow progression to their final destinations in the LHC tunnel, taking about 10 hours to arrive at the furthest point on the LHC ring.

Status and prospects from the LHC

International Nuclear Information System (INIS)

Hawkings, Richard

2010-01-01

This article reviews the status of the CERN Large Hadron Collider and associated experiments as of July 2010. After a brief discussion of the progress in accelerator and experiment commissioning, the LHC physics landscape is presented, together with a selection of the experimental results achieved so far. Finally the prospects for the 2010-11 LHC physics run are reviewed, with an emphasis on possible discoveries in the Higgs and supersymmetry sectors.

Resistive wall instability for the LHC: intermediate review

CERN Document Server

Brandt, D

2001-01-01

As the design of some basic components of the LHC becomes available, it is possible to refine the evaluation of the expected contribution of these elements to the total impedance budget of the machine. The LHC beam-screen being expected to be the main contributor for the resistive wall effect, it appeared justified to review the impedance budget, taking into account the latest available data. This note first recalls the original estimations presented in the LHC Conceptual Design [1], then presents an updated review of the instability rise times and finally discusses a possible reduction of this rather large contribution. ------------- !!Note!!: Please note that updated values for the LHC impedance budget are now available from the report CERN LHC Project Report 585 (Coupled Bunch Instabilities in the LHC, D. Angal-Kalinin and L. Vos, EPAC, July 2002 ).

Synchronous transmission circuit breaker development. Final report

Energy Technology Data Exchange (ETDEWEB)

Garzon, R D

1976-08-01

The need for the development of a synchronous transmission breaker is discussed and the basic preliminary specifications for such a circuit breaker are established and tabulated. The initial exploratory work designed to establish the preferred designs for a synchronous pulse generator, (or current zero predictor), for an operating mechanism and for a suitable interrupter are described in detail. The experimental results obtained with vacuum interrupters and with axial blast interrupters using pure SF/sub 6/, mixtures of SF/sub 6/ and N/sub 2/, and high pressure liquid SF/sub 6/ are reported. The results are then evaluated and the performances obtained with each interrupting media are compared arriving at the end to a choice of a preferred design. This preferred design, an interrupter that uses SF/sub 6/ in the liquid state at pressures of 13.8 megapascals (2000 psi), is completely described. The results obtained in a series of experiments designed to establish limits of performance for this interrupter are also discussed.

Synchronization of chaotic systems

International Nuclear Information System (INIS)

Pecora, Louis M.; Carroll, Thomas L.

2015-01-01

We review some of the history and early work in the area of synchronization in chaotic systems. We start with our own discovery of the phenomenon, but go on to establish the historical timeline of this topic back to the earliest known paper. The topic of synchronization of chaotic systems has always been intriguing, since chaotic systems are known to resist synchronization because of their positive Lyapunov exponents. The convergence of the two systems to identical trajectories is a surprise. We show how people originally thought about this process and how the concept of synchronization changed over the years to a more geometric view using synchronization manifolds. We also show that building synchronizing systems leads naturally to engineering more complex systems whose constituents are chaotic, but which can be tuned to output various chaotic signals. We finally end up at a topic that is still in very active exploration today and that is synchronization of dynamical systems in networks of oscillators

The VFAT3-Comm-Port: a complete communication port for front-end ASICs intended for use within the high luminosity radiation environments of the LHC

International Nuclear Information System (INIS)

Dabrowski, M.; Aspell, P.; Bonacini, S.; Ciaglia, D.; Kloukinas, K.; Lentdecker, G. De; Robertis, G. De; Kupiainen, M.; Talvitie, J.; Tuuva, T.; Leroux, P.; Tavernier, F.

2015-01-01

This paper presents the VFAT3 Comm-Port (V3CP), which offers a single port for all communication to and from a front-end ASIC within the HL-LHC environment. This includes synchronization to the LHC clock, slow control communication, the execution of fast control commands and the readout of data

Results from the LHC Beam Dump Reliability Run

CERN Document Server

Uythoven, J; Carlier, E; Castronuovo, F; Ducimetière, L; Gallet, E; Goddard, B; Magnin, N; Verhagen, H

2008-01-01

The LHC Beam Dumping System is one of the vital elements of the LHC Machine Protection System and has to operate reliably every time a beam dump request is made. Detailed dependability calculations have been made, resulting in expected rates for the different system failure modes. A 'reliability run' of the whole system, installed in its final configuration in the LHC, has been made to discover infant mortality problems and to compare the occurrence of the measured failure modes with their calculations.

The Workflow of LHC Papers

CERN Multimedia

CERN. Geneva

2012-01-01

Finally, the talk will focus on how the institutional repository (CDS) is being linked to the HEP disciplinary archive (INSPIRE) in order to provide users with a central access point to reach LHC results.

Beam Loss and Beam Shape at the LHC Collimators

CERN Document Server

Burkart, Florian

In this master thesis the beam loss and the beam shape at the LHC collimators was measured, analysed, presented and discussed. Beginning with a short introduction of the LHC, the experiments, the supercon- ducting magnet system, the basics on linear beam dynamics and a describtion of the LHC collimation system are given. This is followed by the presentation of the performance of the LHC collimation sys- tem during 2011. A method to convert the Beam Loss Monitor signal in Gy/s to a proton beam loss rate will be introduced. Also the beam lifetime during the proton physics runs in 2011 will be presented and discussed. Finally, the shape of the LHC beams is analysed by using data obtained by scraping the beam at the LHC primary collimators.

Particles are back in the LHC

CERN Multimedia

CERN Bulletin

2016-01-01

The LHC has introduced beam for the first time since the year-end technical stop began in December 2015.   CERN Management and LHC operators applaud as the first beam circulates in the LHC, on Friday 25 March.   On Friday, the LHC opened its doors to allow particles to travel around the ring for the first time since the year-end technical stop (YETS) began in December 2015. At 10:30 a.m., a first bunch was circulating and by midday the beam was circulating in both directions. Progress over the weekend has been good and low intensity beam has already been taken to 6.5 TeV and through the squeeze. Last week, the LHC underwent the final phase of preparation before beam -known as the machine checkout. During this phase all the systems of the LHC are put through their paces without beam. A key part of the process is driving the magnetic circuits, radiofrequency accelerating cavities, collimators, transverse dampers etc. repeatedly through the nominal LHC cycle. A fu...

Reliability review of the LHC collimators low level control system

International Nuclear Information System (INIS)

Masi, A.; Donze, M.; Losito, R.

2011-01-01

The LHC collimators' low level control system is responsible for the positioning, with an accuracy of a few um, of more than 500 motor axes located around the entire LHC tunnel and synchronized at us level,The collimators' axes position is verified in Real Time, monitoring at 100 Hz more than 700 LVDT positioning sensors. Apart from the challenging requirements of timing and positioning accuracy, the system is characterized by a high level of reliability since the collimators have the crucial function of machine protection. In this paper we focus on the architectural and technical choices adopted to guarantee the level of reliability required by the application. We also present the tools and solutions developed to manage this huge control system making the support easier and faster for its operation. (authors)

Time Optimal Synchronization Procedure and Associated Feedback Loops

CERN Document Server

Angoletta, Maria Elena; CERN. Geneva. ATS Department

2016-01-01

A procedure to increase the speed of currently used synchronization loops in a synchrotron by an order of magnitude is presented. Beams dynamics constraint imposes an upper limit on excursions in stable phase angle, and the procedure presented exploits this limit to arrive in the synchronized state from an arbitrary initial state in the fastest possible way. Detailed corrector design for beam phase loop, differential frequency loop and final synchronization loop is also presented. Finally, an overview of the synchronization methods currently deployed in some other CERN’s machines is provided, together with a brief comparison with the newly proposed time-optimal algorithm.

The LHC's suppliers come up trumps

CERN Multimedia

2006-01-01

Four of the LHC Project's most exceptional suppliers have just been honoured in the fifth Golden Hadron awards ceremony. For the first time, a CERN team was among the prize-winners. The CERN main workshop (Mechanical and Materials Engineering group, TS/MME) received the Golden Hadron Award at the prize-giving ceremony held at the Globe. From left to right, Saïd Atieh (TS/MME), Vincent Vuillemin (TS/MME group leader), Michel Caccioppoli (TS/MME), Lyn Evans (LHC Project Leader), Marc Polini (TS/MME-MS section leader), Jean-Luc Gayraud (Cegelec), Jean-Paul Bacher (TS/MME-AS section leader) and Paolo Ciriani (head of the TS Department). Flexible, responsive, committed... all fitting adjectives to describe the recipients of the fifth Golden Hadron awards. The prizes, designed to honour the LHC Project's best suppliers, were awarded to a total of four suppliers, including two that are involved in the final accelerator assembly work: proof, if it were needed, that the project has now entered its final phase. Drak...

Perspectives of SM Higgs measurements at the LHC

Indian Academy of Sciences (India)

... where significant signals can be expected from the LHC experiments. The most sensitive LHC Higgs signatures are reviewed and the discovery year is estimated as a function of the Higgs mass. Finally, we give some ideas about: 'What might be known about the production and decays of a SM Higgs boson' after 10 years ...

Synchronous adenocarcinomas of the colon presenting as synchronous colocolic intussusceptions in an adult

Directory of Open Access Journals (Sweden)

Chen Chuang-Wei

2012-12-01

Full Text Available Abstract Intussusception is uncommon in adults. To our knowledge, synchronous colocolic intussusceptions have never been reported in the literature. Here we described the case of a 59-year-old female of synchronous colocolic intussusceptions presenting as acute abdomen that was diagnosed by CT preoperatively. Laparotomy with radical right hemicolectomy and sigmoidectomy was undertaken without reduction of the invagination due to a significant risk of associated malignancy. The final diagnosis was synchronous adenocarcinoma of proximal transverse colon and sigmoid colon without lymph nodes or distant metastasis. The patient had an uneventful recovery. The case also emphasizes the importance of thorough exploration during surgery for bowel invagination since synchronous events may occur.

Search for heavy resonances in diboson final states with the CMS detector at LHC

Energy Technology Data Exchange (ETDEWEB)

Esch, Thomas; Hebbeker, Thomas; Hoepfner, Kerstin; Mukherjee, Swagata [Physics Institute III A, RWTH Aachen University (Germany)

2016-07-01

The search strategy for heavy resonances decaying to a pair of bosons in proton-proton collisions in the CMS detector at LHC is presented. Several New Physics scenarios including the recently proposed heavy vector triplet (HVT) simplified model predict the existence of Beyond Standard Model (BSM) resonances that have enhanced couplings to boson pairs. This search is particularly challenging, since for large resonance masses the two bosons are boosted and the final decay products are difficult to separate. This requires the development and use of dedicated techniques such as special tau reconstruction and lepton isolation approaches. In the absence of a significant deviation from the Standard Model expectation, upper limits are set on the signal cross section times branching ratio for the HVT signal model.

End of the road for the LHC magnets...well, above ground that is!

CERN Multimedia

2003-01-01

The first LHC dipole cryomagnet has been delivered to the SMI2 building for final assembly prior to lowering it into the LHC tunnel. Over the next 3 years, all LHC cryomagnets will pass through these doors before starting their journey underground.

LHC and the neutrino paradigm

CERN Multimedia

CERN. Geneva

2011-01-01

I argue that LHC may shed light on the nature of neutrino mass through the probe of the seesaw mechanism. The smoking gun signature is lepton number violation through the production of same sign lepton pairs, a collider analogy of the neutrinoless double beta decay. I discuss this in the context of L-R symmetric theories, which predicted neutrino mass long before experiment and led to the seesaw mechanism. A WR gauge boson with a mass in a few TeV region could easily dominate neutrinoless double beta decay, and its discovery at LHC would have spectacular signatures of parity restoration and lepton number violation. I also discuss the collider signatures of the three types of seesaw mechanism, and show how in the case of Type II one can measure the PMNS mixing matrix at the LHC, complementing the low energy probes. Finally, I give an example of a simple realistic SU(5) grand unified theory that predicts the hybrid Type I + III seesaw with a weak fermion triplet at the LHC energies. The seminar will be fol...

Turning the LHC Ring into a New Physics Search Machine

CERN Document Server

Kalliokoski, Matti; Mieskolainen, Mikael; Orava, Risto

2016-01-01

By combining the LHC Beam Loss Monitoring (BLM) system with the LHC experiments, a powerful search machine for new physics beyond the standard model can be realised. The pair of final state protons in the central production process, exit the LHC beam vacuum chamber at locations determined by their fractional momentum losses and will be detected by the BLM detectors. By mapping out the coincident pairs of the BLM identified proton candidates around the four LHC interaction regions, a scan for centrally produced particle states can be made independently of their decay modes.

Scenarios and Technological Challenges for a LHC Luminosity Upgrade: Introduction to the LHC Upgrade Program and Summary of Physics Motivations (1/5)

CERN Multimedia

CERN. Geneva; Michelangelo Mangano

2009-01-01

After a general introduction to the motivations for a LHC upgrade, the lectures will discuss the beam dynamics and technological challenges of the increase of the LHC luminosity, and the possible scenarios. Items such as a stronger final focus with larger aperture magnets, crab cavities, electron cloud issues, beam-beam interaction, machine protection and collimation will be discussed.

Top Physics at CMS/LHC

Directory of Open Access Journals (Sweden)

Daskalakis Georgios

2017-01-01

Full Text Available Recent results on the inclusive and differential production cross sections of top-quark pair and single top-quark processes are presented, obtained using data from proton-proton collisions collected with the CMS detector at the LHC. The large centre-of-mass energies available at LHC allow for the copious production of top-quark pairs in association with other final state particles at high transverse momentum. Measurements of such processes as well as of the top-quark mass and other properties will be discussed. The results are compared with the most up-to-date standard model theory predictions.

Pinning Synchronization of Switched Complex Dynamical Networks

Directory of Open Access Journals (Sweden)

Liming Du

2015-01-01

Full Text Available Network topology and node dynamics play a key role in forming synchronization of complex networks. Unfortunately there is no effective synchronization criterion for pinning synchronization of complex dynamical networks with switching topology. In this paper, pinning synchronization of complex dynamical networks with switching topology is studied. Two basic problems are considered: one is pinning synchronization of switched complex networks under arbitrary switching; the other is pinning synchronization of switched complex networks by design of switching when synchronization cannot achieved by using any individual connection topology alone. For the two problems, common Lyapunov function method and single Lyapunov function method are used respectively, some global synchronization criteria are proposed and the designed switching law is given. Finally, simulation results verify the validity of the results.

LHC magnets: the great descent

CERN Multimedia

2005-01-01

A first dipole magnet was delivered to its final location in the LHC tunnel on Monday, 7 March. This achievement coincides with another important milestone in the installation of the future collider, the completion of the delivery of half the dipole magnets.

Synchronization in complex networks

Energy Technology Data Exchange (ETDEWEB)

Arenas, A.; Diaz-Guilera, A.; Moreno, Y.; Zhou, C.; Kurths, J.

2007-12-12

Synchronization processes in populations of locally interacting elements are in the focus of intense research in physical, biological, chemical, technological and social systems. The many efforts devoted to understand synchronization phenomena in natural systems take now advantage of the recent theory of complex networks. In this review, we report the advances in the comprehension of synchronization phenomena when oscillating elements are constrained to interact in a complex network topology. We also overview the new emergent features coming out from the interplay between the structure and the function of the underlying pattern of connections. Extensive numerical work as well as analytical approaches to the problem are presented. Finally, we review several applications of synchronization in complex networks to different disciplines: biological systems and neuroscience, engineering and computer science, and economy and social sciences.

Synchronous compensators for mini-grids and islanding: final report

Energy Technology Data Exchange (ETDEWEB)

Thornycroft, J.; Caisley, A.; Russell, T.; Willis, S.; Youssef, R.; Bawden, R.; Holden, G.; Williams, J.

2004-07-01

This report presents the findings of a project to develop equipment suitable for the operation of islanded induction generator wind turbines in remote areas with voltage control supplied by synchronous compensators and frequency control supplied by distributed intelligent load controllers. The development of a design methodology for stand-alone wind turbines systems is described, and details are given of its application to the construction of a 25kw Gazelle wind turbine in Sunderland and a 300kW Windmaster wind turbine in Northumberland. Both systems were islanded from the electric grid and fitted with synchronous compensators and distributed intelligent load controllers. The work carried out is listed, and design considerations, system simulation, and the data logging systems are discussed.

Measures of Quantum Synchronization in Continuous Variable Systems

Science.gov (United States)

Mari, A.; Farace, A.; Didier, N.; Giovannetti, V.; Fazio, R.

2013-09-01

We introduce and characterize two different measures which quantify the level of synchronization of coupled continuous variable quantum systems. The two measures allow us to extend to the quantum domain the notions of complete and phase synchronization. The Heisenberg principle sets a universal bound to complete synchronization. The measure of phase synchronization is, in principle, unbounded; however, in the absence of quantum resources (e.g., squeezing) the synchronization level is bounded below a certain threshold. We elucidate some interesting connections between entanglement and synchronization and, finally, discuss an application based on quantum optomechanical systems.

High-precision performance testing of the LHC power converters

CERN Document Server

Bastos, M; Dreesen, P; Fernqvist, G; Fournier, O; Hudson, G

2007-01-01

The magnet power converters for LHC were procured in three parts, power part, current transducers and control electronics, to enable a maximum of industrial participation in the manufacturing and still guarantee the very high precision (a few parts in 10-6) required by LHC. One consequence of this approach was several stages of system tests: factory reception tests, CERN reception tests, integration tests , short-circuit tests and commissioning on the final load in the LHC tunnel. The majority of the power converters for LHC have now been delivered, integrated into complete converter and high-precision performance testing is well advanced. This paper presents the techniques used for high-precision testing and the results obtained.

Supersymmetry and the LHC (Lectures CANCELLED)

CERN Multimedia

CERN. Geneva

2006-01-01

I will first give a pedagogical motivation for, and introduction to, supersymmetric extensions of the Standard Model. The biggest obstacle that prevents theorists from making clear-cut predictions for the production of superparticles at the LHC is our lack of knowledge of how supersymmetry is broken. I will review the most promising SUSY breaking mechanisms that have been suggested so far, and outline the resulting signatures for LHC experiments. Finally, I will try to make contact with other areas of particle physics and cosmology, where supersymmetry also might play a role.

The LHC project

CERN Multimedia

CERN. Geneva

2002-01-01

At the halfway point in the construction of the LHC, the project is now moving from the design and procurement phase to the installation phase, which officially started on 1st March. An overview of the progress of the project is given and the final schedule for installation and commissioning is discussed. The talk will be given in English but questions can be taken in French.

Final Technical Report for ``Paths to Discovery at the LHC : Dark Matter and Track Triggering"

Energy Technology Data Exchange (ETDEWEB)

Hahn, Kristian [Northwestern Univ., Evanston, IL (United States)

2016-10-24

Particle Dark Matter (DM) is perhaps the most compelling and experimentally well-motivated new physics scenario anticipated at the Large Hadron Collider (LHC). The DE-SC0014073 award allowed the PI to define and pursue a path to the discovery of Dark Matter in Run-2 of the LHC with the Compact Muon Solenoid (CMS) experiment. CMS can probe regions of Dark Matter phase-space that direct and indirect detection experiments are unable to constrain. The PI’s team initiated the exploration of these regions, searching specifically for the associated production of Dark Matter with top quarks. The effort focuses on the high-yield, hadronic decays of W bosons produced in top decay, which provides the highest sensitivity to DM produced via through low-mass spin-0 mediators. The group developed identification algorithms that achieve high efficiency and purity in the selection of hadronic top decays, and analysis techniques that provide powerful signal discrimination in Run-2. The ultimate reach of new physics searches with CMS will be established at the high-luminosity LHC (HL-LHC). To fully realize the sensitivity the HL-LHC promises, CMS must minimize the impact of soft, inelastic (“pileup”) interactions on the real-time “trigger” system the experiment uses for data refinement. Charged particle trajectory information (“tracking”) will be essential for pileup mitigation at the HL-LHC. The award allowed the PI’s team to develop firmware-based data delivery and track fitting algorithms for an unprecedented, real-time tracking trigger to sustain the experiment’s sensitivity to new physics in the next decade.

A dedicated LHC collider Beauty experiment for precision measurements of CP-violation. LHC-B letter of intent; TOPICAL

International Nuclear Information System (INIS)

Crosetto, Dario B.

1996-01-01

The LHC-B Collaboration proposes to build a forward collider detector dedicated to the study of CP violation and other rare phenomena in the decays of Beauty particles. The forward geometry results in an average 80 GeV momentum of reconstructed B-mesons and, with multiple, efficient and redundant triggers, yields large event samples. B-hadron decay products are efficiently identified by Ring-Imaging Cerenkov Counters, rendering a wide range of multi-particle final states accessible and providing precise measurements of all angles,(alpha),(beta) and(gamma) of the unitarity triangle. The LHC-B microvertex detector capabilities facilitate multi-vertex event reconstruction and proper-time measurements with an expected few-percent uncertainty, permitting measurements of B(sub s)-mixing well beyond the largest conceivable values of x(sub S). LHC-B would be fully operational at the startup of LHC and requires only a modest luminosity to reveal its full performance potential

Synchronization dynamics of two different dynamical systems

International Nuclear Information System (INIS)

Luo, Albert C.J.; Min Fuhong

2011-01-01

Highlights: → Synchronization dynamics of two distinct dynamical systems. → Synchronization, de-synchronization and instantaneous synchronization. → A controlled pendulum synchronizing with the Duffing oscillator. → Synchronization invariant set. → Synchronization parameter map. - Abstract: In this paper, synchronization dynamics of two different dynamical systems is investigated through the theory of discontinuous dynamical systems. The necessary and sufficient conditions for the synchronization, de-synchronization and instantaneous synchronization (penetration or grazing) are presented. Using such a synchronization theory, the synchronization of a controlled pendulum with the Duffing oscillator is systematically discussed as a sampled problem, and the corresponding analytical conditions for the synchronization are presented. The synchronization parameter study is carried out for a better understanding of synchronization characteristics of the controlled pendulum and the Duffing oscillator. Finally, the partial and full synchronizations of the controlled pendulum with periodic and chaotic motions are presented to illustrate the analytical conditions. The synchronization of the Duffing oscillator and pendulum are investigated in order to show the usefulness and efficiency of the methodology in this paper. The synchronization invariant domain is obtained. The technique presented in this paper should have a wide spectrum of applications in engineering. For example, this technique can be applied to the maneuvering target tracking, and the others.

Final Design and Experimental Validation of the Thermal Performance of the LHC Lattice Cryostats

International Nuclear Information System (INIS)

Bourcey, N.; Capatina, O.; Parma, V.; Poncet, A.; Rohmig, P.; Serio, L.; Skoczen, B.; Tock, J.-P.; Williams, L. R.

2004-01-01

The recent commissioning and operation of the LHC String 2 have given a first experimental validation of the global thermal performance of the LHC lattice cryostat at nominal cryogenic conditions. The cryostat designed to minimize the heat inleak from ambient temperature, houses under vacuum and thermally protects the cold mass, which contains the LHC twin-aperture superconducting magnets operating at 1.9 K in superfluid helium. Mechanical components linking the cold mass to the vacuum vessel, such as support posts and insulation vacuum barriers are designed with efficient thermalisations for heat interception to minimise heat conduction. Heat inleak by radiation is reduced by employing multilayer insulation (MLI) wrapped around the cold mass and around an aluminium thermal shield cooled to about 60 K.Measurements of the total helium vaporization rate in String 2 gives, after substraction of supplementary heat loads and end effects, an estimate of the total thermal load to a standard LHC cell (107 m) including two Short Straight Sections and six dipole cryomagnets. Temperature sensors installed at critical locations provide a temperature mapping which allows validation of the calculated and estimated thermal performance of the cryostat components, including efficiency of the heat interceptions

Final Design and Experimental Validation of the Thermal Performance of the LHC Lattice Cryostats

Science.gov (United States)

Bourcey, N.; Capatina, O.; Parma, V.; Poncet, A.; Rohmig, P.; Serio, L.; Skoczen, B.; Tock, J.-P.; Williams, L. R.

2004-06-01

The recent commissioning and operation of the LHC String 2 have given a first experimental validation of the global thermal performance of the LHC lattice cryostat at nominal cryogenic conditions. The cryostat designed to minimize the heat inleak from ambient temperature, houses under vacuum and thermally protects the cold mass, which contains the LHC twin-aperture superconducting magnets operating at 1.9 K in superfluid helium. Mechanical components linking the cold mass to the vacuum vessel, such as support posts and insulation vacuum barriers are designed with efficient thermalisations for heat interception to minimise heat conduction. Heat inleak by radiation is reduced by employing multilayer insulation (MLI) wrapped around the cold mass and around an aluminium thermal shield cooled to about 60 K. Measurements of the total helium vaporization rate in String 2 gives, after substraction of supplementary heat loads and end effects, an estimate of the total thermal load to a standard LHC cell (107 m) including two Short Straight Sections and six dipole cryomagnets. Temperature sensors installed at critical locations provide a temperature mapping which allows validation of the calculated and estimated thermal performance of the cryostat components, including efficiency of the heat interceptions.

The LHC machine-experiment interface

CERN Multimedia

CERN. Geneva; Tsesmelis, Emmanuel; Brüning, Oliver Sim

2002-01-01

This series of three lectures will provide an overview of issues arising at the interface between the LHC machine and the experiments, which are required for guiding the interaction between the collider and the experiments when operation of the LHC commences. A basic description of the LHC Collider and its operating parameters, such as its energy, currents, bunch structure and luminosity, as well as variations on these parameters, will be given. Furthermore, the optics foreseen for the experimental insertions, the sources and intensities of beam losses and the running-in scenarios for the various phases of operation will be discussed. A second module will cover the specific requirements and expectations of each experiment in terms of the layout of experimental areas, the matters related to radiation monitoring and shielding, the design of the beam pipe and the vacuum system, alignment issues and the measurement of the total cross-section and absolute luminosity by the experiments. Finally an analysis of infor...

QCD-instantons at LHC. Theoretical aspects; QCD-Instantonen am LHC. Theoretische Aspekte

Energy Technology Data Exchange (ETDEWEB)

Petermann, M.

2007-06-15

Instantons are nonperturbative, topologically nontrivial field configurations, which occur in every nonabelian gauge theory. They can be understood as tunneling processes between topologically distinct vacua. Although being a basic theoretical aspect of the Standard Model, a direct experimental verification of instanton processes is still lacking. In this thesis the general discovery potential for QCD-instantons at the LHC is studied in detail by means of instanton perturbation theory. In this context the close correspondence between the leading instanton induced processes at HERA and at LHC becomes important. Essential aspects and differences to deep inelastic scattering can already be revealed by studying the simplest process. Based on these results inclusive cross sections are calculated including the emission of final state gluons. Compared to deep inelastic scattering, a large enhancement of the cross section is found. (orig.)

CMS RPC muon detector performance with 2010-2012 LHC data

CERN Document Server

INSPIRE-00316302; Ban, Y.; Cai, J.; Li, Q.; Liu, S.; Qian, S.; Wang, D.; Xu, Z.; Zhang, F.; Choi, Y.; Kim, D.; Goh, J.; Choi, S.; Hong, B.; Kang, J.W.; Kang, M.; Kwon, J.H.; Lee, K.S.; Lee, S.K.; Park, S.K.; Pant, L.M.; Mohanty, A.K.; Chudasama, R.; Singh, J.B.; Bhatnagar, V.; Mehta, A.; Kumar, R.; Cauwenbergh, S.; Costantini, S.; Cimmino, A.; Crucy, S.; Fagot, A.; Garcia, G.; Ocampo, A.; Poyraz, D.; Salva, S.; Thyssen, F.; Tytgat, M.; Zaganidis, N.; Doninck, W.V.; Cabrera, A.; Chaparro, L.; Gomez, J.P.; Gomez, B.; Sanabria, J.C.; Avila, C.; Ahmad, A.; Muhammad, S.; Shoaib, M.; Hoorani, H.; Awan, I.; Ali, I.; Ahmed, W.; Asghar, M.I.; Shahzad, H.; Sayed, A.; Ibrahim, A.; Aly, S.; Assran, Y.; Radi, A.; Elkafrawy, T.; Sharma, A.; Colafranceschi, S.; Abbrescia, M.; Calabria, C.; Colaleo, A.; Iaselli, G.; Loddo, F.; Maggi, M.; Nuzzo, S.; Radogna, R.; Venditti, R.; Verwilligen, P.; Benussi, L.; Bianco, S.; Piccolo, D.; Paolucci, P.; Buontempo, S.; Cavallo, N.; Merola, M.; Fabozzi, F.; Iorio, O.M.; Braghieri, A.; Montagna, P.; Riccardi, C.; Salvini, P.; Vitulo, P.; Vai, I.; Magnani, A.; Dimitrov, A.; Litov, L.; Pavlov, B.; Petkov, P.; Aleksandrov, A.; Genchev, V.; Iaydjiev, P.; Rodozov, M.; Sultanov, G.; Vutova, M.; Stoykova, S.; Hadjiiska, R.; Ibargüen, H.S.; Morales, M.I.P.; Bernardino, S.C.; Bagaturia, I.; Tsamalaidze, Z.; Crotty, I.; Kim, M.S.

2014-12-05

The muon spectrometer of the CMS (Compact Muon Solenoid) experiment at the Large Hadron Collider (LHC) is equipped with a redundant system made of Resistive Plate Chambers and Drift Tube in barrel and RPC and Cathode Strip Chamber in endcap region. In this paper, the operations and performance of the RPC system during the first three years of LHC activity will be reported. The integrated charge was about 2 mC/cm$^{2}$, for the most exposed detectors. The stability of RPC performance, with particular attention on the stability of detector performance such as efficiency, cluster size and noise, will be reported. Finally, the radiation background levels on the RPC system have been measured as a function of the LHC luminosity. Extrapolations to the LHC design conditions and HL-LHC are also discussed.

Commissioning of the Cryogenics of the LHC Long Straight Sections

CERN Document Server

Perin, A; Claudet, S; Darve, C; Ferlin, G; Millet, F; Parente, C; Rabehl, R; Soubiran, M; van Weelderen, R; Wagner, U

2010-01-01

The LHC is made of eight circular arcs interspaced with eight Long Straight Sections (LSS). Most powering interfaces to the LHC are located in these sections where the particle beams are focused and shaped for collision, cleaning and acceleration. The LSSs are constituted of several unique cryogenic devices and systems like electrical feed-boxes, standalone superconducting magnets, superconducting links, RF cavities and final focusing superconducting magnets. This paper presents the cryogenic commissioning and the main results obtained during the first operation of the LHC Long Straight Sections.

Commissioning of the cryogenics of the LHC long straight sections

International Nuclear Information System (INIS)

Perin, A.; Casas-Cubillos, J.; Claudet, S.; Darve, C.; Ferlin, G.; Millet, F.; Parente, C.; Rabehl, R.; Soubiran, M.; van Weelderen, R.; Wagner, U.

2010-01-01

The LHC is made of eight circular arcs interspaced with eight Long Straight Sections (LSS). Most powering interfaces to the LHC are located in these sections where the particle beams are focused and shaped for collision, cleaning and acceleration. The LSSs are constituted of several unique cryogenic devices and systems like electrical feed-boxes, standalone superconducting magnets, superconducting links, RF cavities and final focusing superconducting magnets. This paper presents the cryogenic commissioning and the main results obtained during the first operation of the LHC Long Straight Sections.

Beyond Standard Model searches in jets plus missing transverse energy final states with the ATLAS experiment at the LHC

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00414488; Alviggi, Mariagrazia; Conventi, Francesco

Dark Matter (DM) is currently one of the most challenging goal in the LHC programme: if DM exists it can be pair-produced in proton-proton collisions. Since its weakly-interacting nature, final signatures with high missing momentum and Standard Model (SM) particles are employed in these searches. This thesis presents results on signatures involving bottom quarks in final states, described in models where DM production occurs via massive spin-0 mediators (scalar or pseudoscalar) with a coupling to SM particles proportional to their masses. These collider searches provide an interesting complementarity to DM direct and indirect detection experiments, covering the parameter space with low DM masses. The results shown in the thesis are obtained on the data collected by the ATLAS experiment in 2015 and 2016.

Non-simplified SUSY. τ-coannihilation at LHC and ILC

Energy Technology Data Exchange (ETDEWEB)

Berggren, M.; Kruecker, D.; List, J.; Melzer-Pellmann, I.A.; Seitz, C. [DESY, Hamburg (Germany); Cakir, A. [DESY, Hamburg (Germany); Istanbul Technical University, Department of Physics Engineering, Istanbul (Turkey); Samani, B.S. [DESY, Hamburg (Germany); IPM, P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Wayand, S. [KIT IEKP, Karlsruhe (Germany)

2016-04-15

If new phenomena beyond the Standard Model will be discovered at the LHC, the properties of the new particles could be determined with data from the High-Luminosity LHC and from a future linear collider like the ILC. We discuss the possible interplay between measurements at the two accelerators in a concrete example, namely a full SUSY model which features a small τ-LSP mass difference. Various channels have been studied using the Snowmass 2013 combined LHC detector implementation in the Delphes simulation package, as well as simulations of the ILD detector concept from the Technical Design Report. We investigate both the LHC and the ILC capabilities for discovery, separation and identification of various parts of the spectrum. While some parts would be discovered at the LHC, there is substantial room for further discoveries at the ILC. We finally highlight examples where the precise knowledge about the lower part of the mass spectrum which could be acquired at the ILC would enable a more in-depth analysis of the LHC data with respect to the heavier states. (orig.)

Search for a Light NMSSM Higgs Boson in the b-Quark Final State at the LHC

International Nuclear Information System (INIS)

Mittag, Gregor

2015-08-01

A search for a light neutral Higgs boson decaying into a pair of b quarks is presented. Such Higgs bosons are predicted by certain scenarios of the Next-to-Minimal Supersymmetric Standard Model (NMSSM), whose Higgs sector has two complex Higgs doublets and an additional Higgs singlet. If the lightest Higgs boson has a sizeable singlet admixture, it may have escaped detection in previous searches at LEP, Tevatron, and LHC, but could be produced at a substantial rate in neutralino decays within supersymmetric cascades. This analysis is the first search for Higgs bosons in the mass range below 100 GeV in the b-quark final state at the LHC. It uses a data sample corresponding to an integrated luminosity of 19.7 fb -1 , which has been recorded by the CMS experiment in 2012 at a centre-of-mass energy of 8TeV. Events with a pair of b-tagged jets, at least two very energetic jets, and large missing energy are selected. The invariant mass of the two selected b-tagged jets is used to extract the signal. The observed invariant-mass spectrum is in good agreement with the background expected from Standard-Model processes. The results are interpreted in terms of cross-section limits and within light-Higgs-boson scenarios of the NMSSM. The modified P4 benchmark scenario of the NMSSM is excluded by this analysis.

LHC Injection Beam Quality During LHC Run I

CERN Document Server

AUTHOR|(CDS)2079186; Kain, Verena; Stapnes, Steinar

The LHC at CERN was designed to accelerate proton beams from 450 GeV to 7 TeV and collide them in four large experiments. The 450 GeV beam is extracted from the last pre-accelerator, the SPS, and injected into the LHC via two 3 km long transfer lines, TI 2 and TI 8. The injection process is critical in terms of preservation of beam quality and machine protection. During LHC Run I (2009-2013) the LHC was filled with twelve high intensity injections per ring, in batches of up to 144 bunches of 1.7*10^11 protons per bunch. The stored beam energy of such a batch is already an order of magnitude above the damage level of accelerator equipment. Strict quality and machine protection requirements at injection have a significant impact on operational efficiency. During the first years of LHC operation, the injection phase was identified as one of the limiting factors for fast LHC turnaround time. The LHC Injection Quality Check (IQC) software framework was developed as a part of this thesis to monitor the beam quality...

5th report from the LHC performance workshop

CERN Multimedia

Bulletin's correspondent from Chamonix

2012-01-01

The morning session on Friday 10 February - the final day of the workshop - saw further examination of the challenges of the High Luminosity LHC and included a look at the state of R&D for the new magnets required for the high luminosity interaction regions. There was then an entertaining look at even more distant future. Possible future projects under consideration include the Large Hadron electron Collider (LHeC) which foresees colliding 60 GeV electrons with 7 TeV protons, and the High Energy LHC (HE-LHC) in which the beam energy of the LHC is increased from 7 to 16.5 TeV. Serious technological challenges exist for both these options. In the afternoon Steve Myers, CERN's Director for Accelerators and Technology, presented a summary of the workshop recommendations. In brief, the LHC should operate at 4 TeV in 2012 with the key priorities being: delivering enough luminosity to ATLAS and CMS to allow them to independently discover or exclude the Higgs; the proton-Lead ion run; and machine deve...

Dipoles for High-Energy LHC

CERN Document Server

Todesco, E; De Rijk, G; Rossi, L

2014-01-01

For the High Energy LHC, a study of a 33 TeV center of mass collider in the LHC tunnel, main dipoles of 20 T operational field are needed. In this paper we first review the conceptual design based on block coil proposed in the Malta workshop, addressing the issues related to coil fabrication and assembly. We then propose successive simplifications of this design, associating a cost estimate of the conductor. We then analyse a block layout for a 15 T magnet. Finally, we consider two layouts based on the D20 and HD2 short models built by LBL. A first analysis of the aspects related to protection of these challenging magnets is given.

Effects of frustration on explosive synchronization

Science.gov (United States)

Huang, Xia; Gao, Jian; Sun, Yu-Ting; Zheng, Zhi-Gang; Xu, Can

2016-12-01

In this study, we consider the emergence of explosive synchronization in scale-free networks by considering the Kuramoto model of coupled phase oscillators. The natural frequencies of oscillators are assumed to be correlated with their degrees and frustration is included in the system. This assumption can enhance or delay the explosive transition to synchronization. Interestingly, a de-synchronization phenomenon occurs and the type of phase transition is also changed. Furthermore, we provide an analytical treatment based on a star graph, which resembles that obtained in scale-free networks. Finally, a self-consistent approach is implemented to study the de-synchronization regime. Our findings have important implications for controlling synchronization in complex networks because frustration is a controllable parameter in experiments and a discontinuous abrupt phase transition is always dangerous in engineering in the real world.

Pinning Synchronization of Linear Complex Coupling Synchronous Generators Network of Hydroelectric Generating Set

Directory of Open Access Journals (Sweden)

Xuefei Wu

2014-01-01

Full Text Available A novel linear complex system for hydroturbine-generator sets in multimachine power systems is suggested in this paper and synchronization of the power-grid networks is studied. The advanced graph theory and stability theory are combined to solve the problem. Here we derive a sufficient condition under which the synchronous state of power-grid networks is stable in disturbance attenuation. Finally, numerical simulations are provided to illustrate the effectiveness of the results by the IEEE 39 bus system.

Message from the Director General Final costs to completion of LHC

CERN Multimedia

Luciano Maiani

2001-01-01

In March this year a review of the costs for the LHC machine was started, which was completed by the end of August. This was a bottom-up review with each group concerned making a projection of the cost to completion of the project. Figures presented were worryingly high. In conjunction, the responses from industries to the calls for tender for essential machine components, especially the superconducting magnet assembly, were also higher than originally anticipated. A summary of this situation was presented to the Finance Committee last week and then to the Committee of Council. After the meetings a summary was prepared by the chairman of Committee of Council which I reprint below. CHAIRMAN'S SUMMARY In the 248th Meeting of the Committee of Council, the Director-General presented a preliminary estimate of the cost to completion of the LHC Project, approved in 1994 and scheduled for commissioning and operation in 2006. Repeating that the project is well advanced and technically sound, the figures presented, s...

LHC physics

National Research Council Canada - National Science Library

Binoth, T

2012-01-01

"Exploring the phenomenology of the Large Hadron Collider (LHC) at CERN, LHC Physics focuses on the first years of data collected at the LHC as well as the experimental and theoretical tools involved...

Nonlinear Dynamics of Controlled Synchronizations of Manipulator System

Directory of Open Access Journals (Sweden)

Qingkai Han

2014-01-01

Full Text Available The nonlinear dynamics of the manipulator system which is controlled to achieve the synchronization motions is investigated in the paper. Firstly, the control strategies and modeling approaches of the manipulator system are given, in which the synchronization goal is defined by both synchronization errors and its derivatives. The synchronization controllers applied on the manipulator system include neuron synchronization controller, improved OPCL synchronization controller, and MRAC-PD synchronization controller. Then, an improved adaptive synchronized control strategy is proposed in order to estimate online the unknown structure parameters and state variables of the manipulator system and to realize the needed synchronous compensation. Furthermore, a robust adaptive synchronization controller is also researched to guarantee the dynamic stability of the system. Finally, the stability of motion synchronizations of the manipulator system possessing nonlinear component is discussed, together with the effect of control parameters and joint friction and others. Some typical motions such as motion bifurcations and the loss of synchronization of it are obtained and illustrated as periodic, multiperiodic, and/or chaotic motion patterns.

2008 LHC Open Days LHC magnets on display

CERN Multimedia

2008-01-01

Over the last few years you’ve probably seen many of the 15 m long blue LHC dipole magnets being ferried around the site. Most of them are underground now, but on the LHC Open Days on 5 and 6 April the magnets will also play a central role on the surface. Installation of one of the LHC dipole magnets on the Saint-Genis roundabout on 7 March. The LHC dipole testing facility with several magnets at various stages of testing. The 27 km ring of the LHC consists of 1232 double-aperture superconducting dipole magnets, 360 short straight sections (SSS) and 114 special SSS for the insertion regions. On the Open Day, you will be able to "Follow the LHC magnets" through different stages around the site, culminating in their descent into the tunnel. Discover all the many components that have to be precisely integrated in the magnet casings, and talk to the engine...

LHC Report: Tests of new LHC running modes

CERN Document Server

Verena Kain for the LHC team

2012-01-01

On 13 September, the LHC collided lead ions with protons for the first time. This outstanding achievement was key preparation for the planned 2013 operation in this mode. Outside of two special physics runs, the LHC has continued productive proton-proton luminosity operation.   Celebrating proton-ion collisions. The first week of September added another 1 fb-1 of integrated luminosity to ATLAS’s and CMS’s proton-proton data set. It was a week of good and steady production mixed with the usual collection of minor equipment faults. The peak performance was slightly degraded at the start of the week but thanks to the work of the teams in the LHC injectors the beam brightness – and thus the LHC peak performance – were restored to previous levels by the weekend. The LHC then switched to new running modes and spectacularly proved its potential as a multi-purpose machine. This is due in large part to the LHC equipment and controls, which have been designed wi...

A line code with quick-resynchronization capability and low latency for the optical data links of LHC experiments

International Nuclear Information System (INIS)

Deng, B; He, M; Chen, J; Guo, D; Hou, S; Teng, P-K; Li, X; Liu, C; Xiang, A C; Ye, J; Gong, D; Liu, T; You, Y

2014-01-01

We propose a line code that has fast resynchronization capability and low latency. Both the encoder and decoder have been implemented in FPGAs. The encoder has also been implemented in an ASIC. The latency of the whole optical link (not including the optical fiber) is estimated to be less than 73.9 ns. In the case of radiation-induced link synchronization loss, the decoder can recover the synchronization in 25 ns. The line code will be used in the ATLAS liquid argon calorimeter Phase-I trigger upgrade and can also be potentially used in other LHC experiments

LHC Injectors Upgrade (LIU) Project at CERN

CERN Document Server

Shaposhnikova, Elena; Damerau, Heiko; Funken, Anne; Gilardoni, Simone; Goddard, Brennan; Hanke, Klaus; Kobzeva, Lelyzaveta; Lombardi, Alessandra; Manglunki, Django; Mataguez, Simon; Meddahi, Malika; Mikulec, Bettina; Rumolo, Giovanni; Scrivens, Richard; Vretenar, Maurizio

2016-01-01

A massive improvement program of the LHC injector chain is presently being conducted under the LIU project. For the proton chain, this includes the replacement of Linac2 with Linac4 as well as all necessary upgrades to the Proton Synchrotron Booster (PSB), the Proton Synchrotron (PS) and Super Proton Synchrotron (SPS), aimed at producing beams with the challenging High Luminosity LHC (HL-LHC) parameters. Regarding the heavy ions, plans to improve the performance of Linac3 and the Low Energy Ion Ring (LEIR) are also pursued under the general LIU program. The full LHC injection chain returned to operation after Long Shutdown 1, with extended beam studies taking place in Run 2. A general project Cost and Schedule Review also took place in March 2015, and several dedicated LIU project reviews were held to address issues awaiting pending decisions. In view of these developments, 2014 and 2015 have been key years to define a number of important aspects of the final LIU path. This paper will describe the reviewed LI...

Installation of the LHC transfer lines begins

CERN Multimedia

Patrice Loïez

2003-01-01

The first of 700 magnets has been installed in one of the two transfer tunnels built to transfer the SPS beam into the LHC. The start of this first installation phase of the LHC transfer lines provides the opportunity to launch a new and highly original modular system for transporting and installing all kinds of magnets in very narrow tunnels. The system is based on very compact bogies, up to four of which can be coupled together to form a convoy. The wheels are fitted with individual motors enabling them to swivel through an angle of 90° and the convoy to move laterally. In this way the magnet is delivered directly to its installation point, but beneath the beamline. It is then raised into its final position in the beamline using air cushions, which form an integrated part of the transport system.Photos 01, 02: Pictured with the newly installed magnet and transport system in the transfer line tunnel are LHC project leader Lyn Evans (second left, white helmet); Volker Mertens, responsible for the LHC injecti...

The latest from the LHC

CERN Multimedia

2009-01-01

Work on closing up sectors in the LHC tunnel. The foreseen shutdown work on the LHC is proceeding well, including the powering tests with the new quench protection system. However, during the past week vacuum leaks have been found in two "cold" sectors of the LHC. The leaks were found in Sectors 8-1 and 2-3 while they were being prepared for the electrical tests on the copper stabilizers at around 80 K. In both cases the leak is at one end of the sector, where the electrical feedbox, DFBA, joins Q7, the final magnet in the sector. Unfortunately, the repair necessitates a partial warm-up of both sectors. This involves the end sub-sector being warmed to room temperature, while the adjacent sub-sector "floats" in temperature and the remainder of the sector is kept at 80 K. As the leak is from the helium circuit to the insulating vacuum, the repair work will have no impact on the vacuum in the beam pipe. However the intervention wil...

LHC Inner Triplet Powering Strategy

CERN Document Server

Bordry, Frederick

2001-01-01

In order to achieve a luminosity in excess of 10**34 cm**-2s**-1 at the Large Hadron Collider (LHC), special high gradient quadrupoles are required for the final focusing triplets. These low-b triplets, located in the four experimental insertions (ATLAS, CMS, ALICE, LHC-B), consist of four wide-aperture superconducting magnets: two outer quadrupoles, Q1 and Q3, with a maximum current of 7 kA and a central one divided into two identical magnets, Q2a and Q2b, with a maximum current of 11.5 kA. To optimise the powering of these mixed quadrupoles, it was decided to use two nested high-current power converters : [8kA, 8V] and [6kA, 8V]. This paper presents the consequence of the interaction between the two galvanically coupled circuits. A control strategy, using two independent, standard, LHC digital controllers, to decouple the two systems is proposed and described. The converter protection during the discharge of the magnet energy due to quenches or interlocks of the magnets are discussed. Simulation and experim...

Commissioning the cryogenic system of the first LHC sector

International Nuclear Information System (INIS)

Millet, F.; Claudet, S.; Ferlin, G.; Perin, A.; Riddone, G.; Serio, L.; Soubiran, M.; Tavian, L.; CERN; Ronayette, L.; GHMFL, Grenoble; Rabehl, R.; Fermilab

2007-01-01

The LHC machine, composed of eight sectors with superconducting magnets and accelerating cavities, requires a complex cryogenic system providing high cooling capacities (18 kW equivalent at 4.5 K and 2.4 W at 1.8 K per sector produced in large cold boxes and distributed via 3.3-km cryogenic transfer lines). After individual reception tests of the cryogenic subsystems (cryogen storages, refrigerators, cryogenic transfer lines and distribution boxes) performed since 2000, the commissioning of the cryogenic system of the first LHC sector has been under way since November 2006. After a brief introduction to the LHC cryogenic system and its specificities, the commissioning is reported detailing the preparation phase (pressure and leak tests, circuit conditioning and flushing), the cool-down sequences including the handling of cryogenic fluids, the magnet powering phase and finally the warm-up. Preliminary conclusions on the commissioning of the first LHC sector will be drawn with the review of the critical points already solved or still pending. The last part of the paper reports on the first operational experience of the LHC cryogenic system in the perspective of the commissioning of the remaining LHC sectors and the beam injection test

LHC Orbit Correction Reproducibility and Related Machine Protection

CERN Document Server

Baer, T; Schmidt, R; Wenninger, J

2012-01-01

The Large Hadron Collider (LHC) has an unprecedented nominal stored beam energy of up to 362 MJ per beam. In order to ensure an adequate machine protection by the collimation system, a high reproducibility of the beam position at collimators and special elements like the final focus quadrupoles is essential. This is realized by a combination of manual orbit corrections, feed forward and real time feedback. In order to protect the LHC against inconsistent orbit corrections, which could put the machine in a vulnerable state, a novel software-based interlock system for orbit corrector currents was developed. In this paper, the principle of the new interlock system is described and the reproducibility of the LHC orbit correction is discussed against the background of this system.

Adaptive synchronization of hyperchaotic Chen system with uncertain parameters

International Nuclear Information System (INIS)

Park, Ju H.

2005-01-01

This article addresses control for the chaos synchronization of hyperchaotic Chen system with five uncertain parameters. Based on the Lyapunov stability theory, an adaptive control law is derived to make the states of two identical hyperchaotic Chen systems asymptotically synchronized. Finally, a numerical simulations is presented to show the effectiveness of the proposed chaos synchronization scheme

signal of NMSSM at the LHC

Indian Academy of Sciences (India)

Jacky Kumar

2017-10-05

Oct 5, 2017 ... γγ + l + /ET signal of NMSSM at the LHC ... mechanism of diphoton mode of A1 and its detection possibility in the final-state. (γγ + l + ... example, it is known for quite sometime that light .... (A) and singlet (S) weak eigenstates.

Heavy ion physics at the LHC

International Nuclear Information System (INIS)

Vogt, R.

2004-01-01

The ion-ion center of mass energies at the LHC will exceed that at RHIC by nearly a factor of 30, providing exciting opportunities for addressing unique physics issues in a completely new energy domain. Some highlights of this new physics domain are presented here. We briefly describe how these collisions will provide new insights into the high density, low momentum gluon content of the nucleus expected to dominate the dynamics of the early state of the system. We then discuss how the dense initial state of the nucleus affects the lifetime and temperature of the produced system. Finally, we explain how the high energy domain of the LHC allows abundant production of ''rare'' processes, hard probes calculable in perturbative quantum chromodynamics, QCD. At the LHC, high momentum jets and b(bar b) bound states, the Υ family, will be produced with high statistics for the first time in heavy ion collisions

Synchronicity from Synchronized Chaos

Directory of Open Access Journals (Sweden)

Gregory S. Duane

2015-03-01

Full Text Available The synchronization of loosely-coupled chaotic oscillators, a phenomenon investigated intensively for the last two decades, may realize the philosophical concept of “synchronicity”—the commonplace notion that related eventsmysteriously occur at the same time. When extended to continuous media and/or large discrete arrays, and when general (non-identical correspondences are considered between states, intermittent synchronous relationships indeed become ubiquitous. Meaningful synchronicity follows naturally if meaningful events are identified with coherent structures, defined by internal synchronization between remote degrees of freedom; a condition that has been posited as necessary for synchronizability with an external system. The important case of synchronization between mind and matter is realized if mind is analogized to a computer model, synchronizing with a sporadically observed system, as in meteorological data assimilation. Evidence for the ubiquity of synchronization is reviewed along with recent proposals that: (1 synchronization of different models of the same objective process may be an expeditious route to improved computational modeling and may also describe the functioning of conscious brains; and (2 the nonlocality in quantum phenomena implied by Bell’s theorem may be explained in a variety of deterministic (hidden variable interpretations if the quantum world resides on a generalized synchronization “manifold”.

Tile Calorimeter Upgrade Program for the Luminosity Increasing at the LHC

CERN Document Server

Cerqueira, Augusto Santiago; The ATLAS collaboration

2015-01-01

The Tile Calorimeter (TileCal) is the central hadronic calorimeter of the ATLAS experiment at the Large Hadron Collider (LHC). TileCal is a sampling calorimeter with approximately 10,000 channels and is operating successfully (data quality efficiency above 99%) in ATLAS, since the start of the LHC collisions. The LHC is scheduled to undergo a major upgrade, in 2022, for the High Luminosity LHC (HL-LHC), where the luminosity will be increased by a factor of 10 above the original design value. The ATLAS upgrade program for high luminosity is split into three phases: Phase 0 occurred during 2013-2014 (Long Shutdown 1), and prepared the LHC for run 2; Phase 1, foreseen for 2019 (Long Shutdown 2), will prepare the LHC for run 3, whereafter the peak luminosity reaches 2-3 x 10^{34} cm^{2}s^{-1}; finally, Phase 2, which is foreseen for 2024 (Long Shutdown 3), will prepare the collider for the HL-LHC operation (5-7 x 10^{34} cm^{2}s^{-1}). The TileCal main activities for Phase 0 were the installation of the new low v...

Tile Calorimeter Upgrade Program for the Luminosity Increasing at the LHC

CERN Document Server

Cerqueira, Augusto Santiago; The ATLAS collaboration

2015-01-01

The Tile Calorimeter (TileCal) is the central hadronic calorimeter of the ATLAS experiment at the Large Hadron Collider (LHC). TileCal is a sampling calorimeter with approximately 10,000 channels and is operating successfully (data quality efficiency above 99%) in ATLAS, since the start of the LHC collisions. The LHC is scheduled to undergo a major upgrade, in 2022, for the High Luminosity LHC (HL-LHC), where the luminosity will be increased by a factor of 10 above the original design value. The ATLAS upgrade program for high luminosity is split into three phases: Phase 0 occurred during 2013-2014 (Long Shutdown 1), and prepared the LHC for run 2; Phase 1, foreseen for 2019 (Long Shutdown 2), will prepare the LHC for run 3, whereafter the peak luminosity reaches 2-3 x 10^{34} cm^{2}s^{-1}; finally, Phase 2, which is foreseen for 2023 (Long Shutdown 3), will prepare the collider for the HL-LHC operation (5-7 x 10^{34} cm^{2}s^{-1}). The TileCal main activities for Phase 0 were the installation of the new low v...

Combination of Run-1 Exotic Searches in Diboson Final States at the LHC

CERN Document Server

Dias, Flavia; Gouzevich, Maxime; Leonidopoulos, Christos; Novaes, Sergio; Oliveira, Alexandra; Pierini, Maurizio; Tomei, Thiago

2016-01-01

We perform a statistical combination of the ATLAS and CMS results for the search of a heavy resonance decaying to a pair of vector bosons with the $\\sqrt{s}=8$~TeV datasets collected at the LHC. We take into account six searches in hadronic and semileptonic final states carried out by the two collaborations. We consider only public information provided by ATLAS and CMS in the HEPDATA database and in papers published in refereed journals. The results are interpreted within the context of a few benchmark new physics models, such as models predicting the existence of a \\PWp or a bulk Randall-Sundum spin--2 resonance. We present exclusion limits, $z$-values, $p$-values and best-fit cross sections in different model interpretations for the combined results. Out of several benchmark exotic models considered in this study, a heavy resonance with a production cross section of $\\sim$5~fb and mass between 1.9 and 2.0 TeV is the scenario most consistent with the experimental results. Models in which a heavy resonance de...

Combination of Run-1 Exotic Searches in Diboson Final States at the LHC

CERN Document Server

Dias, Flavia; Gouzevich, Maxime; Leonidopoulos, Christos; Novaes, Sergio; Oliveira, Alexandra; Pierini, Maurizio; Tomei, Thiago

2016-04-26

We perform a statistical combination of the ATLAS and CMS results for the search of a heavy resonance decaying to a pair of vector bosons with the $\\sqrt{s}=8$~TeV datasets collected at the LHC. We take into account six searches in hadronic and semileptonic final states carried out by the two collaborations. We consider only public information provided by ATLAS and CMS in the HEPDATA database and in papers published in refereed journals. The results are interpreted within the context of a few benchmark new physics models, such as models predicting the existence of a \\PWp or a bulk Randall-Sundum spin--2 resonance. We present exclusion limits, $z$-values, $p$-values and best-fit cross sections in different model interpretations for the combined results. Out of several benchmark exotic models considered in this study, a heavy resonance with a production cross section of $\\sim$5~fb and mass between 1.9 and 2.0 TeV is the scenario most consistent with the experimental results. Models in which a heavy resonance de...

Mechanical Design of the LHC Standard Half-Cell

Science.gov (United States)

Poncet, A.; Brunet, J. C.; Cruikshank, P.; Genet, M.; Parma, V.; Rohmig, P.; Saban, R.; Tavian, L.; Veness, R.; Vlogaert, J.; Williams, L. R.

1997-05-01

The LHC Conceptual Design Report issued on 20th October 1995 (CERN/AC/95-05 (LHC) - nicknamed "Yellow Book") introduced significant changes to some fundamental features of the LHC standard half-cell, composed of one quadrupole, 3 dipoles and a set of corrector magnets. A separate cryogenic distribution line was introduced, which was previously inside the main cryostat. The dipole length has been increased from 10 to 15 m and independent powering of the focusing and defocusing quadrupole magnets was chosen. Individual quench protection diodes were introduced in magnets interconnects and many auxiliary bus bars were added to feed in series the various families of correcting superconducting magnets. The various highly intricate basic systems such as: cryostats and cryogenics feeders, superconducting magnets and their electrical feeding and protection, vacuum beam screen and its cooling, support and alignment devices have been redesigned, taking into account the very tight space available. These space constraints are given by the necessity to have maximum integral bending field strength for maximum LHC energy, and the existing LHC tunnel. Finally, cryogenic and vacuum sectorisation have been introduced to reduce downtimes and facilitate commissioning.

Super and ferric: the first HL-LHC component is ready

CERN Multimedia

Antonella Del Rosso

2016-01-01

Although the actual installation phase in the tunnel will only start in 2024, the first magnet – a sextupole – of the High-Luminosity LHC (HL-LHC) is ready and working according to specifications. This first component is also rather unique as, unlike the superconducting magnets currently used in the LHC, it relies on a “superferric” heart.   An expert in the LASA Laboratory (INFN Milan, Italy) works on assembling the first sextupole corrector of the HL-LHC. (Image: INFN Milan) Although the name might sound completely unfamiliar, superferric magnets were first proposed in the 1980s as a possible solution for high-energy colliders. However, many technical problems had to be overcome before the use of superferric magnets could become a reality. In its final configuration, the HL-LHC will have 36 superferric corrector magnets, of which 4 will be quadrupoles, 8 sextupoles and 24 higher order magnets. In superferric (or “iron-dominated”) magne...

Torsion limits from t t macr production at the LHC

Science.gov (United States)

de Almeida, F. M. L.; de Andrade, F. R.; do Vale, M. A. B.; Nepomuceno, A. A.

2018-04-01

Torsion models constitute a well-known class of extended quantum gravity models. In this work, one investigates the phenomenological consequences of a torsion field interacting with top quarks at the LHC. A torsion field could appear as a new heavy state characterized by its mass and couplings to fermions. This new state would form a resonance decaying into a top antitop pair. The latest ATLAS t t ¯ production results from LHC 13 TeV data are used to set limits on torsion parameters. The integrated luminosity needed to observe torsion resonance at the next LHC upgrades are also evaluated, considering different values for the torsion mass and its couplings to Standard Model fermions. Finally, prospects for torsion exclusion at the future LHC phases II and III are obtained using fast detector simulations.

Synchronous Control Method and Realization of Automated Pharmacy Elevator

Science.gov (United States)

Liu, Xiang-Quan

Firstly, the control method of elevator's synchronous motion is provided, the synchronous control structure of double servo motor based on PMAC is accomplished. Secondly, synchronous control program of elevator is implemented by using PMAC linear interpolation motion model and position error compensation method. Finally, the PID parameters of servo motor were adjusted. The experiment proves the control method has high stability and reliability.

Study of a Tracking/Preshower Detector for the LHC

CERN Multimedia

2002-01-01

% RD-2 Study of a Tracking/Preshower Detector for the LHC \\\\ \\\\An important goal in the design of a detector to operate with high machine luminosity at the LHC is the detection of electrons at either the trigger or analysis level as a signature of rare physics processes. The purpose of this R~\\&~D activity is the study of track-stub/preshower techniques in electron identification. Activities include the study of radiation tolerance for silicon pad counters of the preshower detector, with the associated development of fast, low-noise, radiation hard and low-power electronics readout for the counters. The final aim is the construction of a prototype detector capable of operating at LHC.

Beam Cleaning in Experimental IRs in HL-LHC for the Incoming Beam

CERN Document Server

Garcia-Morales, H; Bruce, Roderik; Redaelli, Stefano

2015-01-01

The HL-LHC will store 675 MJ of energy per beam, about 300 MJ more than the nominal LHC. Due to the increase in stored energy and a different interaction region (IR) optics layout, the collimation system for the incoming beam must be revisited in order to avoid dangerous losses that could cause quenches or machine damage. This paper studies the effectiveness of the current LHC collimation system in intercepting cleaning losses close to the experiments in the HL-LHC. The study reveals that additional tertiary collimators would be beneficial in order to protect not only the final focusing triplets but also the two quadrupoles further upstream.

Searches for the Higgs Boson with the ATLAS detector at the LHC

International Nuclear Information System (INIS)

Mazini, Rachid

2007-01-01

Searching for the Higgs boson lies at the heart of the physics program of the Large Hadron Collider (LHC). The prospects for Higgs searches with the ATLAS detector at the LHC are reviewed. The discovery potential of most prominent Higgs final states predicted by the Standard Model and the MSSM are reviewed. (Author)

Strongly coupled models at the LHC

International Nuclear Information System (INIS)

Vries, Maikel de

2014-10-01

physics and direct searches at the LHC. These tests provide stringent limits on f and the parameter space is slowly driven into the TeV range. Furthermore, a strategy on how to optimise present supersymmetry searches for the Littlest Higgs model with T-parity is presented, with the goal to improve the constraints and yield more stringent limits on f. Finally, the robustness of translating effective operator constraints to beyond the Standard Model (BSM) theories is treated and turns out to crucially depend on the mass and coupling of BSM particles. This is especially relevant for hadron colliders where the partonic centre of mass energy is around the typical energy scales of natural BSM theories. The caveats in applying limits from effective operators are discussed using Z' and G' models, illustrating the effects for a large class of models. This analysis shows that the applicability of effective operators mainly depends on the ratio of the transfer energy in the events and the mass scale of the full theory. Moreover, based on these results a method is developed to recast existing experimental limits on effective operators to the full theory parameter space. It is concluded that strongly coupled models of electroweak symmetry breaking are still natural and compatible with LHC results. Moreover, these types of models provide new and interesting final state topologies for experimental searches at the LHC. For the high energy runs of the LHC these new searches will prove useful in determining the faith of composite models and maybe thereby the origin of electroweak symmetry breaking.

Elementary Particle Interactions with CMS at LHC

International Nuclear Information System (INIS)

Spanier, Stefan

2016-01-01

The High Energy Particle Physics group of the University of Tennessee participates in the search for new particles and forces in proton-proton collisions at the LHC with the Compact Muon Solenoid experiment. Since the discovery of the Higgs boson in 2012, the search has intensified to find new generations of particles beyond the standard model using the higher collision energies and ever increasing luminosity, either directly or via deviations from standard model predictions such as the Higgs boson decays. As part of this effort, the UTK group has expanded the search for new particles in four-muon final states, and in final states with jets, has successfully helped and continues to help to implement and operate an instrument for improved measurements of the luminosity needed for all data analyses, and has continued to conduct research of new technologies for charged particle tracking at a high-luminosity LHC.

Elementary Particle Interactions with CMS at LHC

Energy Technology Data Exchange (ETDEWEB)

Spanier, Stefan [Univ. of Tennessee, Knoxville, TN (United States)

2016-07-31

The High Energy Particle Physics group of the University of Tennessee participates in the search for new particles and forces in proton-proton collisions at the LHC with the Compact Muon Solenoid experiment. Since the discovery of the Higgs boson in 2012, the search has intensified to find new generations of particles beyond the standard model using the higher collision energies and ever increasing luminosity, either directly or via deviations from standard model predictions such as the Higgs boson decays. As part of this effort, the UTK group has expanded the search for new particles in four-muon final states, and in final states with jets, has successfully helped and continues to help to implement and operate an instrument for improved measurements of the luminosity needed for all data analyses, and has continued to conduct research of new technologies for charged particle tracking at a high-luminosity LHC.

Issues in the design of the LHC

CERN Document Server

Evans, Lyndon R; CERN. Geneva

1995-01-01

The lectures aim is to give an overall view of the project rather than a detailed specialized analysis.The main issues are reviewed in the first lecture. After a brief overall description of the machine as foreseen at the present stage of the dessign,the various problems that the design team has to face and the proposed solutions are detailed.The beam dynamics and beam optics problems are briefly discussed. The superconducting magnet technology is presented together with the first models and prototypes results. Some indications are given on the possible strategy for their manufacture.The required performance of the cryogenics system is given,the utilization of the LEP cryogenics plant in the LHC cryogenics system is explained. The implantation of the LHC equipment in underground caverns and in surface buildings is reviewed. Finally some indications are given on the running in of LHC.

Higgs physics at the LHC

CERN Document Server

Mariotti, Chiara

2017-01-01

The first measurements of the mass, the width, and the couplings of the newly discovered Higgs boson at LHC at 7 and 8 TeV center of mass energy will be reviewed. Recent results at 13 TeV center of mass energy will be presented. Finally, searches for additional Higgs bosons in models beyond the standard model will be summarised.

Adaptive synchronization of a new hyperchaotic system with uncertain parameters

International Nuclear Information System (INIS)

Gao Tiegang; Chen Zengqiang; Yuan Zhuzhi; Yu Dongchuan

2007-01-01

This paper discusses control for the master-slave synchronization of a new hyperchaos with five uncertain parameters. An adaptive control law is derived to make the states of two identical hyperchaotic systems asymptotically synchronized based on the Lyapunov stability theory. Finally, a numerical simulation is presented to verify the effectiveness of the proposed synchronization scheme

Synchronization of complex chaotic systems in series expansion form

International Nuclear Information System (INIS)

Ge Zhengming; Yang Chenghsiung

2007-01-01

This paper studies the synchronization of complex chaotic systems in series expansion form by Lyapunov asymptotical stability theorem. A sufficient condition is given for the asymptotical stability of an error dynamics, and is applied to guiding the design of the secure communication. Finally, numerical results are studied for the Quantum-CNN oscillators synchronizing with unidirectional/bidirectional linear coupling to show the effectiveness of the proposed synchronization strategy

Fuzzy stability and synchronization of hyperchaos systems

International Nuclear Information System (INIS)

Wang Junwei; Xiong Xiaohua; Zhao Meichun; Zhang Yanbin

2008-01-01

This paper studies stability and synchronization of hyperchaos systems via a fuzzy-model-based control design methodology. First, we utilize a Takagi-Sugeno fuzzy model to represent a hyperchaos system. Second, we design fuzzy-model-based controllers for stability and synchronization of the system, based on so-called 'parallel distributed compensation (PDC)'. Third, we reduce a question of stabilizing and synchronizing hyperchaos systems to linear matrix inequalities (LMI) so that convex programming techniques can solve these LMIs efficiently. Finally, the generalized Lorenz hyperchaos system is employed to illustrate the effectiveness of our designing controller

Search for Supersymmetry in Multileptonic Final States with Collimated $\\tau$ Pairs with the ATLAS Detector at the LHC

CERN Document Server

AUTHOR|(CDS)2096586; Kroha, Hubert; Junggeburth, Johannes Josef; Zinonos, Zinonas

The search for supersymmetry (SUSY) is a major part of the ATLAS physics program. Due to the low Standard Model background the search for four-lepton final states provides excellent sensitivity to R-parity violating SUSY models where the lightest supersymmetric particle (LSP), produced in pairs, decay into two charged leptons and a neutrino. For LSP decays into hadronically decaying $\\tau$ pairs, however, the current analysis is not sensitive if the mass difference between the LSP and the next heavier supersymmetric particle is large, because the $\\tau$ jet become highly collimated and the standard $\\tau$ pair reconstruction method is not able to resolve them. A new specialized collimated $\\tau$ pair reconstruction method has been developed for LHC run-2 at 13~TeV center-of-mass energy. In this thesis, the new method is evaluated and optimized for the search for SUSY in four-lepton final states. It is shown, that exclusion limits can be extended to lower LSP masses with the new di-$\\tau$ reconstruction. Fur...

The LHC magnets' trip underground

CERN Multimedia

2002-01-01

Buildings SMI 2 and SDI 2 are currently a big blue construction at the end of the Meyrin site. When they are finished, in 2003, they will be the departure point from where the magnets for the LHC will be lowered down into the tunnel. View of the new building at the end of the Meyrin site. If you live in neighbouring France, you have probably noticed a new blue steel construction that has changed the view from Saint Genis Pouilly since last March. It's the first of two contiguous buildings, SMI 2 and SDI 2, which will make it possible to prepare and lower the 1232 dipole magnets, the 400 short straight sections and some 60 insertion magnets down into the TI2 tunnel, and from there, to their final location in the LHC tunnel. According to Paul Faugeras, Technical Co-ordinator for the LHC machine, 'the installation of the magnets will start in early 2004, and hopefully everything will be done by October 2006'. The first part of the magnets' journey will take place on surface. The 15 metre-long dipole magnets a...

Consolidation of the LHC superconducting magnets and circuits during LS1

International Nuclear Information System (INIS)

Tock, J.P.

2012-01-01

All the activities necessary to consolidate the LHC superconducting magnets and circuits are presented, especially the consolidation of the main splices, replacement of weak cryo-magnets, the consolidation of the DFBAs (electrical feed-boxes) and the special interventions. For each of them, the baseline strategy is presented, highlighting the reasons that led to these choices and the remaining risk level. In particular, the progress of the work of the LHC Splices Task Force, the recommendations of the second LHC Splices Review (November 2011) and their analysis are reported. Finally, the work planning, the organization chart and the associated resources are detailed. (author)

Anti-Synchronization of Chaotic Systems via Adaptive Sliding Mode Control

International Nuclear Information System (INIS)

Jawaada, Wafaa; Noorani, M. S. M.; Al-Sawalha, M. Mossa

2012-01-01

An anti-synchronization scheme is proposed to achieve the anti-synchronization behavior between chaotic systems with fully unknown parameters. A sliding surface and an adaptive sliding mode controller are designed to gain the anti-synchronization. The stability of the error dynamics is proven theoretically using the Lyapunov stability theory. Finally numerical results are presented to justify the theoretical analysis

HL-LHC and HE-LHC Upgrade Plans and Opportunities for US Participation

Science.gov (United States)

Apollinari, Giorgio

2017-01-01

The US HEP community has identified the exploitation of physics opportunities at the High Luminosity-LHC (HL-LHC) as the highest near-term priority. Thanks to multi-year R&D programs, US National Laboratories and Universities have taken the leadership in the development of technical solutions to increase the LHC luminosity, enabling the HL-LHC Project and uniquely positioning this country to make critical contributions to the LHC luminosity upgrade. This talk will describe the shaping of the US Program to contribute in the next decade to HL-LHC through newly developed technologies such as Nb3Sn focusing magnets or superconducting crab cavities. The experience gained through the execution of the HL-LHC Project in the US will constitute a pool of knowledge and capabilities allowing further developments in the future. Opportunities for US participations in proposed hadron colliders, such as a possible High Energy-LHC (HE-LHC), will be described as well.

Search for the Standard Model Higgs boson produced in association with top quark pairs in multi-leptonic final states with the ATLAS detector at the LHC

CERN Document Server

Milesi, Marco; Andreazza, Attilio

The search for the Standard Model (SM) Higgs boson produced in association with top quarks - known as $t\\bar{t}H$ production - plays a crucial role in the Large Hadron Collider (LHC) physics programme, as it allows a direct measurement of the Higgs field Yukawa coupling to the heaviest fermion and can constrain effects of new physics beyond the Standard Model in the top coupling sector. This thesis presents a search for the $t\\bar{t}H$ production in an inclusive multi-leptonic final state, with a proton-proton collision dataset corresponding to an integrated luminosity of $\\int L dt = 36.1~\\mathrm{fb}^{−1}$, collected by the ATLAS experiment at the LHC in 2015 and 2016 at a centre-of-mass energy of $\\sqrt{s}=13~\\mathrm{TeV}$.
 The final state is characterised by high jet multiplicity, and the presence of several electrons and muons, as well as hadronically decaying tau leptons. The multiplicity of these physics objects allows the definition of several categories to enhance the sensitivity of the analysis...

Synchronization of Harb-Zohdy Chaotic System via Back-Stepping Design

Directory of Open Access Journals (Sweden)

M. R. Shamsyeh Zahedi∗

2015-12-01

Full Text Available This paper is concerned with the problem of synchronization of the Harb-Zohdy chaotic system using the back-stepping. Based on the stability theory, the control for the synchronization of chaotic systems Harb-Zohdy is considered without unknown parameters. Next, an adaptive back-stepping control law is derived to generate an error signal between the drive and response systems Harb-Zohdy with an uncertain parameter asymptotically synchronized. Finally, this method is extended to synchronize the system with two unknown parameters. Note that the method presented here needs only one controller to realize the synchronization. Numerical simulations indicate the effectiveness of the proposed chaos synchronization scheme

LHC Report: LHC hit the target!

CERN Multimedia

Enrico Bravin for the LHC team

2016-01-01

Last week, the accumulated integrated luminosity reached the target value for 2016 of 25 fb-1 in both ATLAS and CMS.   The integrated luminosity delivered to ATLAS and CMS reached (and already passed!) 25 fb-1– the target for the whole year! Tuesday, 30 August was just a regular day for the 2016 LHC run. However,  on that day, the integrated luminosity delivered to ATLAS and CMS reached 25 fb-1 – the target for the whole year! How did we get here? A large group of committed scientists and technical experts work behind the scenes at the LHC, ready to adapt to the quirks of this truly impressive machine. After the push to produce as many proton-proton collisions as possible before the summer conferences, several new ideas and production techniques (such as Bunch Compression Multiple Splitting, BCMS) have been incorporated in the operation of LHC in order to boost its performance even further. Thanks to these improvements, the LHC was routinely operated with peak luminos...

Quench Performance of the LHC Insertion Magnets

CERN Document Server

Lasheras, N C; Siemko, A; Ostojic, R; Kirby, G

2009-01-01

After final installation in the LHC tunnel, the MQM and MQY quadrupole magnets of the LHC insertions are now being commissioned to their nominal currents. These two types of magnets operate at 1.9 K and 4.5 K and with nominal currents ranging from 3600 A to 5390 A. From the very first acceptance tests of the bare magnets coming from the manufacturers, they have been powered using different cycles, in different configurations, at different temperatures and in different tests facilities. In this paper we present the global results of these powering tests. We aim at separating common from individual features of these groups of magnets. Temperature dependence of the training, temperature margin, and ultimate current can be extracted from these tests. As these magnets are used to match the optics and the dispersion in the machine, the projected ultimate current at which they can be operated is critical in view of operation of LHC.

Quantum synchronization in an optomechanical system based on Lyapunov control.

Science.gov (United States)

Li, Wenlin; Li, Chong; Song, Heshan

2016-06-01

We extend the concepts of quantum complete synchronization and phase synchronization, which were proposed in A. Mari et al., Phys. Rev. Lett. 111, 103605 (2013)PRLTAO0031-900710.1103/PhysRevLett.111.103605, to more widespread quantum generalized synchronization. Generalized synchronization can be considered a necessary condition or a more flexible derivative of complete synchronization, and its criterion and synchronization measure are proposed and analyzed in this paper. As examples, we consider two typical generalized synchronizations in a designed optomechanical system. Unlike the effort to construct a special coupling synchronization system, we purposefully design extra control fields based on Lyapunov control theory. We find that the Lyapunov function can adapt to more flexible control objectives, which is more suitable for generalized synchronization control, and the control fields can be achieved simply with a time-variant voltage. Finally, the existence of quantum entanglement in different generalized synchronizations is also discussed.

Linearly and nonlinearly bidirectionally coupled synchronization of hyperchaotic systems

International Nuclear Information System (INIS)

Zhou Jin; Lu Junan; Wu Xiaoqun

2007-01-01

To date, there have been many results about unidirectionally coupled synchronization of chaotic systems. However, much less work is reported on bidirectionally-coupled synchronization. In this paper, we investigate the synchronization of two bidirectionally coupled Chen hyperchaotic systems, which are coupled linearly and nonlinearly respectively. Firstly, linearly coupled synchronization of two hyperchaotic Chen systems is investigated, and a theorem on how to choose the coupling coefficients are developed to guarantee the global asymptotical synchronization of two coupled hyperchaotic systems. Analysis shows that the choice of the coupling coefficients relies on the bound of the chaotic system. Secondly, the nonlinearly coupled synchronization is studied; a sufficient condition for the locally asymptotical synchronization is derived, which is independent of the bound of the hyperchaotic system. Finally, numerical simulations are included to verify the effectiveness and feasibility of the developed theorems

Theoretical predictions for charm and bottom production at the LHC

CERN Document Server

Cacciari, Matteo; Houdeau, Nicolas; Mangano, Michelangelo L; Nason, Paolo; Ridolfi, Giovanni

2012-01-01

We present predictions for a variety of single-inclusive observables that stem from the production of charm and bottom quark pairs at the 7 TeV LHC. They are obtained within the FONLL semi-analytical framework, and with two "Monte Carlo + NLO" approaches, MC@NLO and POWHEG. Results are given for final states and acceptance cuts that are as close as possible to those used by experimental collaborations and, where feasible, are compared to LHC data.

LHC beam energy in 2012

International Nuclear Information System (INIS)

Siemko, A.; Charifouline, Z.; Dahlerup-Petersen, K.; Denz, R.; Ravaioli, E.; Schmidt, R.; Verweij, A.

2012-01-01

The interconnections between the LHC main magnets are made of soldered joints (splices) of two superconducting cables stabilized by a copper bus bar. The measurements performed in 2009 in the whole machine, in particular in sector 3-4 during the repair after the 2008 accident, demonstrated that there is a significant fraction of defective copper bus bar joints in the machine. In this paper, the limiting factors for operating the LHC at higher energies with defective 13 kA bus bar joints are briefly reviewed. The experience gained during the 2011 run, including the quench statistics and dedicated quench propagation tests impacting on maximum safe energy are presented. The impact of the by-pass diode contact resistance issue is also addressed. Finally, a proposal for running at the highest possible safe energy compatible with the pre-defined risk level is presented. (authors)

LHC Beam Energy in 2012

CERN Document Server

Siemko, A; Dahlerup-Petersen, K; Denz, R; Ravaioli, E; Schmidt, R; Verweij, A

2012-01-01

The interconnections between the LHC main magnets are made of soldered joints (splices) of two superconducting cables stabilized by a copper bus bar. The measurements performed in 2009 in the whole machine, in particular in sector 3-4 during the repair after the 2008 accident, demonstrated that there is a significant fraction of defective copper bus bar joints in the machine. In this paper, the limiting factors for operating the LHC at higher energies with defective 13 kA bus bar joints are briefly reviewed. The experience gained during the 2011 run, including the quench statistics and dedicated quench propagation tests impacting on maximum safe energy are presented. The impact of the by-pass diode contact resistance issue is also addressed. Finally, a proposal for running at the highest possible safe energy compatible with the pre-defined risk level is presented.

Beleaguered LHC gears up for restart

CERN Multimedia

Cartwright, Jon

2009-01-01

"The Large Hadron Collider (LHC) is finally set to restart in mid-November following last year's accident. Initially it will collide protons at an energy of only 3.5 TeV per beam, and staff at Cern will have to wait until late next year before trying to run the collider at its maximum energy" (0.75 page)

Trigger and data-acquisition challenges at the LHC

CERN Multimedia

CERN. Geneva

2003-01-01

We review the main requirements placed on the Trigger and Data Acquisition (DAQ systems of the LHC experiments by their rich physics program and the LHC environment. A description of the architecture of the various systems, the motivation of each alternative and the conceptual design of each filtering stage will be discussed. We will then turn to a description of the major elements of the three distinct sub-systems, namely the Level-1 trigger, the DAQ with particular attention to the Event-Building and overall control and monitor, and finally the High-Level trigger system and the online farms.

Transverse emittance measurement and preservation at the LHC

Energy Technology Data Exchange (ETDEWEB)

Kuhn, Maria

2016-06-20

. During LHC Run 1 significant transverse emittance growth throughout the LHC cycle was observed. About 30 % of the potential luminosity performance was lost through the different phases of the LHC cycle. At the LHC design stage the total allowed emittance increase through the cycle was set to 7 %. Measurements indicated that most of the blow-up occurred during the injection plateau and the ramp. Intra-beam scattering was one of the main drivers for emittance growth. In April 2015 the LHC re-started with a collision energy of 6.5 TeV per beam. This thesis presents the first transverse emittance preservation studies in LHC Run 2 with 25 ns beams. A breakdown of the growth throughout the various phases in the LHC cycle is given for low intensity beams measured with wire scanners. Also presented is data collected from synchrotron light monitors and the LHC experiments. Finally, the emittance growth results is compared to intra-beam scattering simulations. A theory on emittance growth due to noise from the LHC transverse damper and other external sources is discussed. The results of the investigations are summarized, and an outlook in terms of emittance blow-up for future LHC upgrade scenarios with low emittance beams is given.

The LHC babies

CERN Multimedia

Laëtitia Pedroso

2011-01-01

With the machine restart and first collisions at 3.5 TeV, 2009 and 2010 were two action-packed years at the LHC. The events were a real media success, but one important result that remained well hidden was the ten births in the LHC team over the same period. The mothers – engineers, cryogenics experts and administrative assistants working for the LHC – confirm that it is possible to maintain a reasonable work-life balance. Two of them tell us more…   Verena Kain (left) and Reyes Alemany (right) in the CERN Control Centre. With the LHC running around the clock, LHC operations engineers have high-pressure jobs with unsociable working hours. These past two years, which will undoubtedly go down in the annals of CERN history, the LHC team had their work cut out, but despite their high-octane professional lives, several female members of the team took up no less of a challenge in their private lives, creating a mini-baby-boom by which the LHC start-up will also be remembe...

A 120 mm Bore Quadrupole for the Phase 1 LHC Upgrade

CERN Document Server

Fessia, P; Borgnolutti, F; Regis, F; Richter, D; Todesco, E

2010-01-01

The phase I LHC upgrade foresees the installation of a new final focusing for the high luminosity experiences in order to be able to focus the beams in the interaction points to b*~ 0.25 cm. Key element of this upgrade is a large bore (120 mm) superconducting quadrupole. This article proposes a magnet design that will make use of the LHC main dipole superconducting cable. Due to the schedule constraints and to the budget restrictions, it is mandatory to integrate in the design the maximum number of features successfully used during the LHC construction. This paper presents this design option and the rationales behind the several technical choices.

Physics potential of precision measurements of the LHC luminosity

CERN Multimedia

CERN. Geneva

2012-01-01

The uncertainty in the determination of the LHC luminosity is rapidly becoming a limiting factor for the analysis and interpretation of many important LHC processes. In this talk first of all we discuss the theoretical accuracy of total cross sections and examine in which cases the luminosity error is or will be dominant. We then review the impact of LHC data in PDF determinations, with enphasis on the effects of the luminosity uncertainty. We explore the requirements for the accuracy of the 2011 luminosity determination from the point of view of standard candle cross section and other important processes. Finally we discuss what we can learn from the accurate measurement of cross section ratios at different center of mass energies for processes like W, ttbar and dijet production.

Small-world networks exhibit pronounced intermittent synchronization

Science.gov (United States)

Choudhary, Anshul; Mitra, Chiranjit; Kohar, Vivek; Sinha, Sudeshna; Kurths, Jürgen

2017-11-01

We report the phenomenon of temporally intermittently synchronized and desynchronized dynamics in Watts-Strogatz networks of chaotic Rössler oscillators. We consider topologies for which the master stability function (MSF) predicts stable synchronized behaviour, as the rewiring probability (p) is tuned from 0 to 1. MSF essentially utilizes the largest non-zero Lyapunov exponent transversal to the synchronization manifold in making stability considerations, thereby ignoring the other Lyapunov exponents. However, for an N-node networked dynamical system, we observe that the difference in its Lyapunov spectra (corresponding to the N - 1 directions transversal to the synchronization manifold) is crucial and serves as an indicator of the presence of intermittently synchronized behaviour. In addition to the linear stability-based (MSF) analysis, we further provide global stability estimate in terms of the fraction of state-space volume shared by the intermittently synchronized state, as p is varied from 0 to 1. This fraction becomes appreciably large in the small-world regime, which is surprising, since this limit has been otherwise considered optimal for synchronized dynamics. Finally, we characterize the nature of the observed intermittency and its dominance in state-space as network rewiring probability (p) is varied.

Final report on the Controlled Cold Helium Spill Test in the LHC tunnel at CERN

CERN Document Server

Dufay-Chanat, L; Casas-Cubillos, J; Chorowski, M; Grabowski, M; Jedrusyna, A; Lindell, G; Nonis, M; Koettig, T; Vauthier, N; van Weelderen, R; Winkler, T

2015-01-01

The 27 km circumference LHC underground tunnel is a space in which the helium cooled LHC magnets are installed. The vacuum enclosures of the superconducting magnets are protected by over-pressure safety relief devices that open whenever cold helium escapes either from the magnet cold enclosure or from the helium supply headers, into this vacuum enclosure. A 3-m long no stay zone around these devices is defined based on scale model studies, protecting the personnel against cold burns or asphyxia caused by such a helium release event. Recently, several simulation studies have been carried out modelling the propagation of the helium/air mixture, resulting from the opening of such a safety device, along the tunnel. The released helium flows vary in the range between 1 kg/s and 0.1 kg/s. To validate these different simulation studies, real life mock-up tests have been performed inside the LHC tunnel, releasing helium flow rates of 1 kg/s, 0.3 kg/s and 0.1 kg/s. For each test, up to 1000 liters of liquid helium wer...

Impulsive Cluster Synchronization in Community Network with Nonidentical Nodes

International Nuclear Information System (INIS)

Deng Liping; Wu Zhaoyan

2012-01-01

In this paper, cluster synchronization in community network with nonidentical nodes and impulsive effects is investigated. Community networks with two kinds of topological structure are investigated. Positive weighted network is considered first and external pinning controllers are designed for achieving cluster synchronization. Cooperative and competitive network under some assumptions is investigated as well and can achieve cluster synchronization with only impulsive controllers. Based on the stability analysis of impulsive differential equation and the Lyapunov stability theory, several simple and useful synchronization criteria are derived. Finally, numerical simulations are provided to verify the effectiveness of the derived results.

RF upgrade program in LHC injectors and LHC machine

International Nuclear Information System (INIS)

Jensen, E.

2012-01-01

The main themes of the RF upgrade program are: the Linac4 project, the LLRF-upgrade and the study of a tuning-free wide-band system for PSB, the upgrade of the SPS 800 MHz amplifiers and beam controls and the upgrade of the transverse dampers of the LHC. Whilst LHC Splice Consolidation is certainly the top priority for LS1, some necessary RF consolidation and upgrade is necessary to assure the LHC performance for the next 3- year run period. This includes: 1) necessary maintenance and consolidation work that could not fit the shorter technical stops during the last years, 2) the upgrade of the SPS 200 MHz system from presently 4 to 6 cavities and possibly 3) the replacement of one LHC cavity module. On the longer term, the LHC luminosity upgrade requires crab cavities, for which some preparatory work in SPS Coldex must be scheduled during LS1. (author)

LHC@home is ready to support HiLumi LHC: take part!

CERN Multimedia

CERN Bulletin

2011-01-01

Recently relaunched, the LHC@home volunteer computing project is now ready to support the HiLumi LHC project, the design phase of the planned upgrade of the LHC that will increase its luminosity by a factor of 5 to 10 beyond its original design value. HiLumi will need massive simulations to test the beam dynamics. Whether you are at home or at work, you can help experts design the future LHC by connecting your computer to LHC@home. Go for it!   LHC@home is aimed at involving the public in real science. If you have a computer that is connected to the Internet, you can join the large team of volunteers who are already supporting its two main projects: Test4Theory, which runs computer simulations of high-energy particle collisions, and SixTrack, which is aimed at optimizing the LHC performance by performing beam dynamics simulations. In both cases, the software is designed to run only when your computer is idle and causes no disruption to your normal activities. To the simulations run by the Six...

Some LHC milestones...

CERN Multimedia

2008-01-01

October 1995 The LHC technical design report is published. This document details the operation and the architecture of the future accelerator. November 2000 The first of the 1232 main dipole magnets for the LHC are delivered. May 2005 The first interconnection between two magnets of the accelerator is made. To carry out the 1700 interconnections of the LHC, 123 000 operations are necessary. February 2006 The new CERN Control Centre, which combines all the control rooms for the accelerators, the cryogenics and the technical infrastructure, starts operation. The LHC will be controlled from here. October 2006 Construction of the largest refrigerator in the world is complete. The 27 km cryogenic distribution line inside the LHC tunnel will circulate helium in liquid and gas phases to provide cryogenic conditions for the superconducting magnets of the accelerator. November 2006 Magnet production for the LHC is complete. The last of t...

Prospects for R-Parity Conserving SUSY searches at the LHC

CERN Document Server

The ATLAS collaboration

2009-01-01

The talk reviews the current strategies to search for generic SUSY models with R-parity conservation in the ATLAS and CMS detectors at the LHC. The discovery reach in early data is presented for different search channels based on missing transverse momentum from undetected neutralinos and multiple jets. The talk will also describe the search for models of gauge-mediated supersymmetry breaking for which the NLSP is a neutralino decaying to a photon and a gravitino. In this scenario, the search strategy exploits the distinct signature of a non-pointing photon. Finally, we present recent work on techniques used to reconstruct the decays of SUSY particles at the LHC in early data, based on the selection of final-state exclusive decay chains.

Robust fixed-time synchronization of delayed Cohen-Grossberg neural networks.

Science.gov (United States)

Wan, Ying; Cao, Jinde; Wen, Guanghui; Yu, Wenwu

2016-01-01

The fixed-time master-slave synchronization of Cohen-Grossberg neural networks with parameter uncertainties and time-varying delays is investigated. Compared with finite-time synchronization where the convergence time relies on the initial synchronization errors, the settling time of fixed-time synchronization can be adjusted to desired values regardless of initial conditions. Novel synchronization control strategy for the slave neural network is proposed. By utilizing the Filippov discontinuous theory and Lyapunov stability theory, some sufficient schemes are provided for selecting the control parameters to ensure synchronization with required convergence time and in the presence of parameter uncertainties. Corresponding criteria for tuning control inputs are also derived for the finite-time synchronization. Finally, two numerical examples are given to illustrate the validity of the theoretical results. Copyright © 2015 Elsevier Ltd. All rights reserved.

QCD-instantons at LHC. Theoretical aspects

International Nuclear Information System (INIS)

Petermann, M.

2007-06-01

Instantons are nonperturbative, topologically nontrivial field configurations, which occur in every nonabelian gauge theory. They can be understood as tunneling processes between topologically distinct vacua. Although being a basic theoretical aspect of the Standard Model, a direct experimental verification of instanton processes is still lacking. In this thesis the general discovery potential for QCD-instantons at the LHC is studied in detail by means of instanton perturbation theory. In this context the close correspondence between the leading instanton induced processes at HERA and at LHC becomes important. Essential aspects and differences to deep inelastic scattering can already be revealed by studying the simplest process. Based on these results inclusive cross sections are calculated including the emission of final state gluons. Compared to deep inelastic scattering, a large enhancement of the cross section is found. (orig.)

Operational beams for the LHC

CERN Document Server

Papaphilippou, Y.; Rumolo, G.; Manglunki, D.

2014-01-01

The variety of beams, needed to set-up in the injectors as requested in the LHC, are reviewed, in terms of priority but also performance expectations and reach during 2015. This includes the single bunch beams for machine commissioning and measurements (probe, Indiv) but also the standard physics beams with 50 ns and 25 ns bunch spacing and their high brightness variants using the Bunch Compression Merging and Splitting (BCMS) scheme. The required parameters and target performance of special beams like the doublet for electron cloud enhancement and the more exotic 8b$\\oplus$4e beam, compatible with some post-scrubbing scenarios are also described. The progress and plans for the LHC ion production beams during 2014-2015 are detailed. Highlights on the current progress of the setting up of the various beams are finally presented with special emphasis on potential performance issues across the proton and ion injector chain.

Electroweak Physics at the LHC

CERN Document Server

Sommer, Philip; The ATLAS collaboration

2018-01-01

With the large integrated luminosities recorded at the LHC and the excellent understanding of the LHC detectors, it is possible to measure electroweak observables to the highest precision. A review of the measurement of the $W$ boson mass by the ATLAS Collaboration as well as a new measurement of the electroweak mixing angle with the CMS detector are presented. Special emphasis is put on a discussion of the modelling uncertainties and the potential of the latest low-$\\mu$ runs, recorded at the end of 2017 by both collaboration. In addition, the latest measurements of multi-boson final states as well as the electroweak production of single gauge bosons at 13 TeV are summarised. The study of these processes can be used to constrain anomalous gauge couplings in an effective field theory approach, allowing to bridge tests of the electroweak sector of the Standard Models also to Higgs boson production.

The LHC machine: from beam commissioning to operation and future upgrades

CERN Document Server

Giovannozzi, Massimo

2015-01-01

This chapter describes the current status of the LHC. General machine parameters are reviewed and the beam commissioning process is presented, showing the evolution of the machine’s performance over recent years. The highlights of the powerful complex of injectors are described, in order to provide a global picture of the impressive performance of CERN’s flagship machine, which relies on both the astonishing quality of the LHC itself and the incredible flexibility of the injectors. The focus is on proton physics performance, with emphasis on the different possible scenarios leading to an upgrade of the LHC performance. Finally, the prospects for the development of the machine into the far future are briefly discussed.

LHC Report: a record start for LHC ion operation

CERN Multimedia

Jan Uythoven for the LHC Team

2011-01-01

After the technical stop, the LHC switched over to ion operation, colliding lead-ions on lead-ions. The recovery from the technical stop was very smooth, and records for ion luminosity were set during the first days of ion operation.   The LHC technical stop ended on the evening of Friday, 11 November. The recovery from the technical stop was extremely smooth, and already that same evening ion beams were circulating in the LHC. ‘Stable beams’ were declared the same night, with 2 x 2 bunches of ions circulating in the LHC, allowing the experiments to have their first look at ion collisions this year. However, the next step-up in intensity – colliding 170 x 170 bunches – was postponed due to a vacuum problem in the PS accelerator, so the collisions on Sunday, 13 November were confined to 9 x 9 bunches. The vacuum problem was solved, and on the night of Monday, 14 November, trains of 24 lead bunches were injected into the LHC and 170 x 170 bunches were brough...

H∞ synchronization of chaotic systems via dynamic feedback approach

International Nuclear Information System (INIS)

Lee, S.M.; Ji, D.H.; Park, Ju H.; Won, S.C.

2008-01-01

This Letter considers H ∞ synchronization of a general class of chaotic systems with external disturbance. Based on Lyapunov theory and linear matrix inequality (LMI) formulation, the novel feedback controller is established to not only guarantee stable synchronization of both master and slave systems but also reduce the effect of external disturbance to an H ∞ norm constraint. A dynamic feedback control scheme is proposed for H ∞ synchronization in chaotic systems for the first time. Then, a criterion for existence of the controller is given in terms of LMIs. Finally, a numerical simulation is presented to show the effectiveness of the proposed chaos synchronization scheme

Installation of the LHC transfer lines begins

CERN Multimedia

Patrice Loïez

2003-01-01

The first of 700 magnets has been installed in one of the two transfer tunnels built to transfer the SPS beam into the LHC. The start of this first installation phase of the LHC transfer lines provides the opportunity to launch a new and highly original modular system for transporting and installing all kinds of magnets in very narrow tunnels. The system is based on very compact bogies, up to four of which can be coupled together to form a convoy. The wheels are fitted with individual motors enabling them to swivel through an angle of 90° and the convoy to move laterally. In this way the magnet is delivered directly to its installation point, but beneath the beamline. It is then raised into its final position in the beamline using air cushions, which form an integrated part of the transport system.Photo 01: Pictured with the newly installed magnet and transport system in the transfer line tunnel are (left to right) Volker Mertens, responsible for the LHC injection and transfer lines; personnel involved in tr...

LHC Report: staying cool despite record highs

CERN Document Server

Jorg Wenninger for the LHC team

2016-01-01

These two last weeks have been a highlight of LHC operation so far, delivering record luminosity.   LHC integrated luminosity in 2011, 2012, 2015 and 2016. It’s been a record-breaking period for the LHC. On the evening of Wednesday, 1 June, the maximum number of bunches achievable with the current configuration, based on the injection of 72-bunch trains with a spacing of 25 ns, was reached. 2040 bunches were circulating in the machine. The rest of the week continued in a similar vein: the luminosity record at 6.5 TeV was broken with a peak luminosity of just over 8 x 1033 cm-2s-1, reaching 80% of the design luminosity. This was followed by a new record for integrated luminosity in a single fill, with 370 pb-1 delivered in 18 hours of colliding beams. Finally, a third record was broken later in the week: with an availability for collisions of around 75% (the annual average is normally around 35%) and 6 long fills of particles brought into collision one...

LHC Report: machine commissioning - drawing to a close

CERN Multimedia

Belen Salvachua Ferrando for the LHC team

2016-01-01

The recommissioning of the LHC is going well: the machine has delivered first pilot Stable Beams collisions.   Some of the first collisions recorded by the experiments during the LHC 2016 commissioning with low-intensity stable beams. (Image: CERN)   TOTEM bump The main goal of the past couple of weeks was to advance with the preparation of collimators settings and protection devices. Over the weekend of 16-17 April, collisions were re-established after setting up a new orbit bump around the Roman Pot locations in IP5 (TOTEM), in order to improve their acceptance. The bump was smoothly incorporated into the machine settings that lead into Stable Beams. The LHC orbit was corrected towards the reference leaving the machine ready for the next steps: aperture measurements and final collimator alignment. Alignment and aperture at 40 cm The aperture is the available space in the transverse plane of the machine. Detailed simulations are used to predict the minimum machine aperture. At ...

Search for supersymmetry in a final state containing two photons and missing transverse momentum in √s = 13 TeV pp collisions at the LHC using the ATLAS detector

Czech Academy of Sciences Publication Activity Database

Aaboud, M.; Aad, G.; Abbott, B.; Chudoba, Jiří; Havránek, Miroslav; Hejbal, Jiří; Jakoubek, Tomáš; Kepka, Oldřich; Kupčo, Alexander; Kůs, Vlastimil; Lokajíček, Miloš; Lysák, Roman; Marčišovský, Michal; Mikeštíková, Marcela; Němeček, Stanislav; Penc, Ondřej; Šícho, Petr; Staroba, Pavel; Svatoš, Michal; Taševský, Marek; Vrba, Václav

2016-01-01

Roč. 76, č. 9 (2016), 1-34, č. článku 517. ISSN 1434-6044 Institutional support: RVO:68378271 Keywords : CERN LHC Coll * final state * two-photon * background * ATLAS * new physics * neutralino * mass Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 5.331, year: 2016

Theoretical Modeling and Experimental Investigation of the Thermal Performance of the LHC Prototype Lattice Cryostats

CERN Document Server

Riddone, G

1997-01-01

This thesis presents the thermal performance of the LHC (Large Hadron Collider) prototype cryostats both in steady-state and in transient conditions. LHC will be built in the 27 km LEP tunnel and will provide proton-proton collisions. It will make use of superconducting magnets operating in static bath of superfluid helium at 1.9 K. The thesis is mainly divided in three parts. The first part cont ains three chapters which present a brief overview of the LHC project. Part 1-Chapter 1 gives a short introduction to the LHC design layout and performance. Part 1-Chapter 2 refers to LHC cryogenic s ystem and describes the general architecture of the cryogenic plants, the temperature levels and the heat loads. The 50 m long LHC prototype half-cell contains one twin-bore quadrupole and four twin-a perture dipoles. In Part 1-Chapter 3 the design and construction of the prototype dipole and quadrupole cryostats are presented. The LHC prototype cryostats have integrated cryogenic lines, while the final LHC cryostats hav...

Synchronization Between Two Different Switched Chaotic Systems By Switching Control

Directory of Open Access Journals (Sweden)

Du Li Ming

2016-01-01

Full Text Available This paper is concerned with the synchronization problem of two different switched chaotic systems, considering the general case that the master-slave switched chaotic systems have uncertainties. Two basic problems are considered: one is projective synchronization of switched chaotic systems under arbitrary switching; the other is projective synchronization of switched chaotic systems by design of switching when synchronization cannot achieved by using any subsystems alone. For the two problems, common Lyapunov function method and multiple Lyapunov function method are used respectively, an adaptive control scheme has been presented, some sufficient synchronization conditions are attainted, and the switching signal is designed. Finally, the numerical simulation is provide to show the effectiveness of our method.

Observability of inert scalars at the LHC

Energy Technology Data Exchange (ETDEWEB)

Hashemi, Majid [Shiraz University, Physics Department, College of Sciences, Shiraz (Iran, Islamic Republic of); Najjari, Saereh [University of Warsaw, Faculty of Physics, Warsaw (Poland)

2017-09-15

In this work we investigate the observability of inert doublet model scalars at the LHC operating at the center of mass energy of 14 TeV. The signal production process is pp → AH{sup ±} → ZHW{sup ±}H leading to two different final states of l{sup +}l{sup -}HjjH and l{sup +}l{sup -}Hl{sup ±}νH based on the hadronic and leptonic decay channels of the W boson. All the relevant background processes are considered and an event selection is designed to distinguish the signal from the large Standard Model background. We found that signals of the selected search channels are well observable at the LHC with an integrated luminosity of 300 fb{sup -1}. (orig.)

LHC report

CERN Multimedia

CERN. Geneva

2010-01-01

This week's Report, by Gianluigi Arduini,  will be included in the LHC Physics Day, dedicated to the reviews of the LHC physics results presented at ICHEP 2010. Seehttp://indico.cern.ch/conferenceDisplay.py?confId=102669 

PDF4LHC recommendations for LHC Run II

NARCIS (Netherlands)

Butterworth, Jon; Carrazza, Stefano; Cooper-Sarkar, Amanda; Roeck, Albert de; Feltesse, Joel; Forte, Stefano; Gao, Jun; Glazov, Sasha; Huston, Joey; Kassabov, Zahari; McNulty, Ronan; Morsch, Andreas; Nadolsky, Pavel; Radescu, Voica; Rojo, Juan; Thorne, Robert S.

2015-01-01

We provide an updated recommendation for the usage of sets of parton distribution functions (PDFs) and the assessment of PDF and PDF+$\\alpha_s$ uncertainties suitable for applications at the LHC Run II. We review developments since the previous PDF4LHC recommendation, and discuss and compare the new

Keeping HL-LHC accountable

CERN Multimedia

2015-01-01

This week saw the cost and schedule of the High Luminosity LHC (HL-LHC) and LHC Injectors Upgrade (LIU) projects come under close scrutiny from the external review committee set up for the purpose.    HL-LHC, whose implementation requires an upgrade to the CERN injector complex, responds directly to one of the key recommendations of the updated European Strategy for Particle Physics, which urges CERN to prepare for a ‘major luminosity upgrade’, a recommendation that is also perfectly in line with the P5 report on the US strategy for the field. Responding to this recommendation, CERN set up the HL-LHC project in 2013, partially supported by FP7 funding through the HiLumi LHC Design Study (2011-2015), and coordinated with the American LARP project, which oversees the US contribution to the upgrade. A key element of HL-LHC planning is a mechanism for receiving independent expert advice on all aspects of the project.  To this end, several technical reviews h...

O(t-α)-synchronization and Mittag-Leffler synchronization for the fractional-order memristive neural networks with delays and discontinuous neuron activations.

Science.gov (United States)

Chen, Jiejie; Chen, Boshan; Zeng, Zhigang

2018-04-01

This paper investigates O(t -α )-synchronization and adaptive Mittag-Leffler synchronization for the fractional-order memristive neural networks with delays and discontinuous neuron activations. Firstly, based on the framework of Filippov solution and differential inclusion theory, using a Razumikhin-type method, some sufficient conditions ensuring the global O(t -α )-synchronization of considered networks are established via a linear-type discontinuous control. Next, a new fractional differential inequality is established and two new discontinuous adaptive controller is designed to achieve Mittag-Leffler synchronization between the drive system and the response systems using this inequality. Finally, two numerical simulations are given to show the effectiveness of the theoretical results. Our approach and theoretical results have a leading significance in the design of synchronized fractional-order memristive neural networks circuits involving discontinuous activations and time-varying delays. Copyright © 2018 Elsevier Ltd. All rights reserved.

Electroweak Physics at the LHC

CERN Document Server

Sommer, Philip; The ATLAS collaboration

2018-01-01

With the high integrated luminosities recorded at the LHC and the very good understanding of the LHC detectors, it is possible to measure electroweak observables to the highest precision. In this talk, we review the measurement of the W boson mass by the ATLAS Collaboration as well as the new measurement of the electroweak mixing angle with the CMS detector. Special focus is drawn on a discussion of the modeling uncertainties and the physics potential of the latest low-mu runs, recorded at the end of 2017 by both collaboration. In addition, we will present the latest measurements of multi-boson final states as well as the electroweak production of single gauge bosons at 13 TeV. The study of these processes can be used to constrain anomalous gauge couplings in an effective field theory approach, allowing to bridge tests of the electroweak sector of the Standard Models also to the Higgs-boson production.

LHC-B: a dedicated LHC collider beauty experiment

International Nuclear Information System (INIS)

Erhan, S.

1995-01-01

LHC-B is a forward detector optimized for the study of CP-violation and other rare phenomena in the decays of beauty particles at the LHC. An open geometry forward detector design, with good mass, vertex resolution and particle identification, will facilitate the collection of a large numbers of event samples in diverse B decay channels and allow for a thorough understanding of the systematic uncertainties. With the expected large event statistics, LHC-B will be able to test the closure of the unitarity triangle and make sensitive tests of the Standard Model description of CP-violation. Here we describe the experiment and summarize its anticipated performance. (orig.)

External post-operational checks for the LHC beam dumping system

International Nuclear Information System (INIS)

Magnin, N.; Baggiolini, V.; Carlier, E.; Goddard, B.; Gorbonosov, R.; Khasbulatov, D.; Uythoven, J.; Zerlauth, M.

2012-01-01

The LHC Beam Dumping System (LBDS) is a critical part of the LHC machine protection system. After every LHC beam dump action the various signals and transient data recordings of the beam dumping control systems and beam instrumentation measurements are automatically analysed by the external Post-Operational Checks (XPOC) system to verify the correct execution of the dump action and the integrity of the related equipment. This software system complements the LHC machine protection hardware, and has to ascertain that the beam dumping system is 'as good as new' before the start of the next operational cycle. This is the only way by which the stringent reliability requirements can be met. The XPOC system has been developed within the framework of the LHC 'Post-Mortem' system, allowing highly dependable data acquisition, data archiving, live analysis of acquired data and replay of previously recorded events. It is composed of various analysis modules, each one dedicated to the analysis of measurements coming from specific equipment. This paper describes the global architecture of the XPOC system and gives examples of the analyses performed by some of the most important analysis modules. It explains the integration of the XPOC into the LHC control infrastructure along with its integration into the decision chain to allow proceeding with beam operation. Finally, it discusses the operational experience with the XPOC system acquired during the first years of LHC operation, and illustrates examples of internal system faults or abnormal beam dump executions which it has detected. (authors)

Final report on the Controlled Cold Helium Spill Test in the LHC tunnel at CERN

International Nuclear Information System (INIS)

Dufay-Chanat, L; Bremer, J; Casas-Cubillos, J; Koettig, T; Vauthier, N; Van Weelderen, R; Winkler, T; Chorowski, M; Grabowski, M; Jedrusyna, A; Lindell, G; Nonis, M

2015-01-01

The 27 km circumference LHC underground tunnel is a space in which the helium cooled LHC magnets are installed. The vacuum enclosures of the superconducting magnets are protected by over-pressure safety relief devices that open whenever cold helium escapes either from the magnet cold enclosure or from the helium supply headers, into this vacuum enclosure. A 3-m long no stay zone around these devices is defined based on scale model studies, protecting the personnel against cold burns or asphyxia caused by such a helium release event. Recently, several simulation studies have been carried out modelling the propagation of the helium/air mixture, resulting from the opening of such a safety device, along the tunnel. The released helium flows vary in the range between 1 kg/s and 0.1 kg/s. To validate these different simulation studies, real life mock-up tests have been performed inside the LHC tunnel, releasing helium flow rates of 1 kg/s, 0.3 kg/s and 0.1 kg/s. For each test, up to 1000 liters of liquid helium were released under standard operational tunnel conditions. The data recorded include oxygen concentration, temperature and flow speed measurements, and video footage used to assess qualitatively the visibility. These measurements have been made in the up- and downstream directions, with respect to the air ventilation flow, of the spill point.This paper presents the experimental set-up under which these release tests were made, the effects of these releases on the atmospheric tunnel condition as a function of the release flow rate. We discuss the modification to the personnel access conditions to the LHC tunnel that are presently implemented as a result of these tests. (paper)

Final report on the Controlled Cold Helium Spill Test in the LHC tunnel at CERN

Science.gov (United States)

Dufay-Chanat, L.; Bremer, J.; Casas-Cubillos, J.; Chorowski, M.; Grabowski, M.; Jedrusyna, A.; Lindell, G.; Nonis, M.; Koettig, T.; Vauthier, N.; van Weelderen, R.; Winkler, T.

2015-12-01

The 27 km circumference LHC underground tunnel is a space in which the helium cooled LHC magnets are installed. The vacuum enclosures of the superconducting magnets are protected by over-pressure safety relief devices that open whenever cold helium escapes either from the magnet cold enclosure or from the helium supply headers, into this vacuum enclosure. A 3-m long no stay zone around these devices is defined based on scale model studies, protecting the personnel against cold burns or asphyxia caused by such a helium release event. Recently, several simulation studies have been carried out modelling the propagation of the helium/air mixture, resulting from the opening of such a safety device, along the tunnel. The released helium flows vary in the range between 1 kg/s and 0.1 kg/s. To validate these different simulation studies, real life mock-up tests have been performed inside the LHC tunnel, releasing helium flow rates of 1 kg/s, 0.3 kg/s and 0.1 kg/s. For each test, up to 1000 liters of liquid helium were released under standard operational tunnel conditions. The data recorded include oxygen concentration, temperature and flow speed measurements, and video footage used to assess qualitatively the visibility. These measurements have been made in the up- and downstream directions, with respect to the air ventilation flow, of the spill point. This paper presents the experimental set-up under which these release tests were made, the effects of these releases on the atmospheric tunnel condition as a function of the release flow rate. We discuss the modification to the personnel access conditions to the LHC tunnel that are presently implemented as a result of these tests.

ALICE measurements of heavy-flavour production at the LHC

CERN Multimedia

CERN. Geneva

2012-01-01

The measurement of open charm and beauty production in Pb-Pb collisions at the LHC gives access to the mechanisms of heavy-quark transport and energy loss in hot and dense QCD matter. The ALICE apparatus allows us to measure heavy flavour particles over a wide acceptance, using hadronic and electronic final states at central rapidity and muonic final states at forward rapidity, in both cases with coverage down to low transverse momentum. These measurements, in pp collisions, besides constituting the reference for the heavy-ion studies, provide acceptance-wise unique information on heavy-quark production at LHC energies. After presenting results for pp collisions at centre-of-mass energies of 2.76 and 7 TeV, we focus on the observation of the suppression of heavy-flavour production in central Pb-Pb collisions and of the azimuthal anisotropy of charmed hadrons in semi-central collisions at 2.76 TeV.

Mueller Navelet jets at LHC - complete NLL BFKL calculation

Energy Technology Data Exchange (ETDEWEB)

Colferai, Dimitri [Firenze Univ. (Italy). Dipt. di Fisica; INFN, Florence (Italy); Schwennsen, Florian [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Szymanowski, Lech [Soltan Inst. for Nuclear Studies, Warsaw (Poland); Ecole Polytechnique, CNRS, Palaiseau (France). CPHT; Wallon, Samuel [Paris-Sud Univ., CNRS, Orsay (France). LPT; UPMC Univ. Paris 06 (France). Faculte de Physique

2010-03-15

We calculate cross section and azimuthal decorrelation of Mueller Navelet jets at the LHC in the complete next-lo-leading order BFKL framework, i.e. including next-to-leading corrections to the Green's function as well as next-to-leading corrections to the Mueller Navelet vertices. The obtained results for standard observables proposed for studies of Mueller Navelet jets show that both sources of corrections are of equal, big importance for final magnitude and final behavior of observables. The astonishing conclusion of our analysis is that the observables obtained within the complete next-lo-leading order BFKL framework of the present paper are quite similar to the same observables obtained within next-to-leading logarithm DGLAP type treatment. This fact sheds doubts on general belief that the studies of Mueller Navelet jets at the LHC will lead to clear discrimination between the BFKL and the DGLAP dynamics. (orig.)

Mueller Navelet jets at LHC - complete NLL BFKL calculation

International Nuclear Information System (INIS)

Colferai, Dimitri; Schwennsen, Florian; Szymanowski, Lech; Ecole Polytechnique, CNRS, Palaiseau; Wallon, Samuel; UPMC Univ. Paris 06

2010-03-01

We calculate cross section and azimuthal decorrelation of Mueller Navelet jets at the LHC in the complete next-lo-leading order BFKL framework, i.e. including next-to-leading corrections to the Green's function as well as next-to-leading corrections to the Mueller Navelet vertices. The obtained results for standard observables proposed for studies of Mueller Navelet jets show that both sources of corrections are of equal, big importance for final magnitude and final behavior of observables. The astonishing conclusion of our analysis is that the observables obtained within the complete next-lo-leading order BFKL framework of the present paper are quite similar to the same observables obtained within next-to-leading logarithm DGLAP type treatment. This fact sheds doubts on general belief that the studies of Mueller Navelet jets at the LHC will lead to clear discrimination between the BFKL and the DGLAP dynamics. (orig.)

JACoW Configuring and automating an LHC experiment for faster and better physics output

CERN Document Server

Gaspar, Clara; Alessio, Federico; Barbosa, Joao; Cardoso, Luis; Frank, Markus; Jost, Beat; Neufeld, Niko; Schwemmer, Rainer

2018-01-01

LHCb has introduced a novel online detector alignment and calibration for LHC Run II. This strategy allows for better trigger efficiency, better data quality and direct physics analysis at the trigger output. This implies: running a first High Level Trigger (HLT) pass synchronously with data taking and buffering locally its output; use the data collected at the beginning of the fill, or on a run-by-run basis, to determine the new alignment and calibration constants; run a second HLT pass on the buffered data using the new constants. Operationally, it represented a challenge: it required running different activities concurrently in the farm, starting at different times and load balanced depending on the LHC state. However, these activities are now an integral part of LHCb's dataflow, seamlessly integrated in the Experiment Control System and completely automated under the supervision of LHCb's 'Big Brother'. In total, for all activities, there are usually around 60000 tasks running in the ~1600 nodes of the fa...

"New Tools for Forecasting Old Physics at the LHC"

CERN Document Server

CERN. Geneva

2011-01-01

For the LHC to uncover many types of new physics, the "old physics" produced by the Standard Model must be understood very well. For decades, the central theoretical tool for this job was the Feynman diagram expansion. However, Feynman diagrams are just too slow, even on fast computers, to allow adequate precision for complicated LHC events with many jets in the final state. Such events are already visible in the initial LHC data. Over the past few years, alternative methods to Feynman diagrams have come to fruition. These new "on-shell" methods are based on the old principles of unitarity and factorization. They can be much more efficient because they exploit the underlying simplicity of scattering amplitudes, and recycle lower-loop information. I will describe how and why these methods work, and present some of the recent state-of-the-art results that have been obtained with them.

Transitions amongst synchronous solutions in the stochastic Kuramoto model

Science.gov (United States)

DeVille, Lee

2012-05-01

We consider the Kuramoto model of coupled oscillators with nearest-neighbour coupling and additive white noise. We show that synchronous solutions which are stable without the addition of noise become metastable and that we have transitions amongst synchronous solutions on long timescales. We compute these timescales and, moreover, compute the most likely path in phase space that transitions will follow. We show that these transition timescales do not increase as the number of oscillators in the system increases, and are roughly constant in the system size. Finally, we show that the transitions correspond to a splitting of one synchronous solution into two communities which move independently for some time and which rejoin to form a different synchronous solution.

Magnetic field measurements of LHC inner triplet quadrupoles fabricated at Fermilab

International Nuclear Information System (INIS)

Velev, G.V.; Bossert, R.; Carcagno, R.; DiMarco, J.; Feher, S.; Kashikhin, V.V.; Kerby, J.; Lamm, M.; Orris, D.; Schlabach, P.; Strait, J.

2006-01-01

Fermilab, as part of the US-LHC Accelerator Project, is producing superconducting low-beta quadrupole magnets for the Large Hadron Collider (LHC). These 5.5 m long magnets are designed to operate in superfluid helium at 1.9 K with a nominal gradient of 205 T/m in the 70 mm bore. Two quadrupoles separated by a dipole orbit corrector in a single cryogenic assembly comprise the Q2 optical elements of the final focus triplets in the LHC interaction regions. The field quality of the quadrupoles is measured at room temperature during construction of the cold masses as well as during cold testing of the cryogenic assembly. We summarize data from the series measurements of the magnets and discuss various topics of interest

Magnetic field measurements of LHC inner triplet quadrupoles fabricated at Fermilab

Energy Technology Data Exchange (ETDEWEB)

Velev, G.V.; Bossert, R.; Carcagno, R.; DiMarco, J.; Feher, S.; Kashikhin, V.V.; Kerby, J.; Lamm, M.; Orris, D.; Schlabach, P.; Strait, J.; /Fermilab

2006-08-01

Fermilab, as part of the US-LHC Accelerator Project, is producing superconducting low-beta quadrupole magnets for the Large Hadron Collider (LHC). These 5.5 m long magnets are designed to operate in superfluid helium at 1.9 K with a nominal gradient of 205 T/m in the 70 mm bore. Two quadrupoles separated by a dipole orbit corrector in a single cryogenic assembly comprise the Q2 optical elements of the final focus triplets in the LHC interaction regions. The field quality of the quadrupoles is measured at room temperature during construction of the cold masses as well as during cold testing of the cryogenic assembly. We summarize data from the series measurements of the magnets and discuss various topics of interest.

FLUKA Monte Carlo simulations and benchmark measurements for the LHC beam loss monitors

International Nuclear Information System (INIS)

Sarchiapone, L.; Brugger, M.; Dehning, B.; Kramer, D.; Stockner, M.; Vlachoudis, V.

2007-01-01

One of the crucial elements in terms of machine protection for CERN's Large Hadron Collider (LHC) is its beam loss monitoring (BLM) system. On-line loss measurements must prevent the superconducting magnets from quenching and protect the machine components from damages due to unforeseen critical beam losses. In order to ensure the BLM's design quality, in the final design phase of the LHC detailed FLUKA Monte Carlo simulations were performed for the betatron collimation insertion. In addition, benchmark measurements were carried out with LHC type BLMs installed at the CERN-EU high-energy Reference Field facility (CERF). This paper presents results of FLUKA calculations performed for BLMs installed in the collimation region, compares the results of the CERF measurement with FLUKA simulations and evaluates related uncertainties. This, together with the fact that the CERF source spectra at the respective BLM locations are comparable with those at the LHC, allows assessing the sensitivity of the performed LHC design studies

FLUKA Monte Carlo simulations and benchmark measurements for the LHC beam loss monitors

Science.gov (United States)

Sarchiapone, L.; Brugger, M.; Dehning, B.; Kramer, D.; Stockner, M.; Vlachoudis, V.

2007-10-01

One of the crucial elements in terms of machine protection for CERN's Large Hadron Collider (LHC) is its beam loss monitoring (BLM) system. On-line loss measurements must prevent the superconducting magnets from quenching and protect the machine components from damages due to unforeseen critical beam losses. In order to ensure the BLM's design quality, in the final design phase of the LHC detailed FLUKA Monte Carlo simulations were performed for the betatron collimation insertion. In addition, benchmark measurements were carried out with LHC type BLMs installed at the CERN-EU high-energy Reference Field facility (CERF). This paper presents results of FLUKA calculations performed for BLMs installed in the collimation region, compares the results of the CERF measurement with FLUKA simulations and evaluates related uncertainties. This, together with the fact that the CERF source spectra at the respective BLM locations are comparable with those at the LHC, allows assessing the sensitivity of the performed LHC design studies.

The LHC cryogenic system and operational experience from the first three years run

International Nuclear Information System (INIS)

Delikaris, Dimitri; Tavian, Laurent

2014-01-01

The LHC (Large Hadron Collider) accelerator helium cryogenic system consists of eight cryogenically independent sectors, each 3.3 km long, all cooled and operated at 1.9 K. The overall, entropy equivalent, installed cryogenic capacity totalizes 144 kW (a) 4.5 K including 19.2 kW (a) 1.8 K with an associated helium inventory of 130 ton. The LHC cryogenic system is considered among the most complex and powerful in the world allowing the cooling down to superfluid helium temperature of 1.9 K. of the accelerators' high field superconducting magnets distributed over the 26.7 km underground ring. The present article describes the LHC cryogenic system and its associated cryogen infrastructure. Operational experience, including cryogen management, acquired from the first three years of LHC operation is finally presented. (author)

LHC Olympics Workshop and String Phenomenology 2006 Conference

Energy Technology Data Exchange (ETDEWEB)

David Gross

2006-10-01

This is the final report of the organizers of the String Phenomenolgy program of which the LHC Olympics and the String Phenomenolgy conference were a part. In addition, it includes the list of talks from our website which comprise the online proceedings. The KITP no longer publishes conferences proceedings but rather makes recordings and visuals of all talks available on its website at www.kitp.ucsb.edu Program talks are available at http://online.kitp.ucsb.edu/online/strings06/ Conference talks are are at http://online.itp.ucsb.edu/online/strings_c06/ and LHC Olympics talks are at http://online.itp.ucsb.edu/online/lhco_c06/. These talks constitute the proceedings of these meetings.

Commissioning of the 400 MHz LHC RF System

CERN Document Server

Ciapala, Edmond; Baudrenghien, P; Brunner, O; Butterworth, A; Linnecar, T; Maesen, P; Molendijk, J; Montesinos, E; Valuch, D; Weierud, F

2008-01-01

The installation of the 400 MHz superconducting RF system in LHC is finished and commissioning is under way. The final RF system comprises four cryo-modules each with four cavities in the LHC tunnel straight section round IP4. Also underground in an adjacent cavern shielded from the main tunnel are the sixteen 300 kW klystron RF power sources with their high voltage bunkers, two Faraday cages containing RF feedback and beam control electronics, and racks containing all the slow controls. The system and the experience gained during commissioning will be described. In particular, results from conditioning the cavities and their movable main power couplers and the setting up of the low level RF feedbacks will be presented.

Study of ZZ diboson final states in the leptons-neutrinos decay channel with the CMS experiment at the LHC at CERN

International Nuclear Information System (INIS)

Marionneau, M.

2011-09-01

This thesis presents a study of ZZ final states performed with data recorded with the CMS detector at LHC. This study exploits the first data delivered by the LHC and recorded by CMS in 2010 and 2011. The ZZ production cross section is measured and limits are set on neutral electroweak triple gauge couplings. The measurement of the production cross-section of ZZ has given: σ(pp → ZZ) equals (11.24 ± 3.18 (stat) ± 1.98 (syst) ± 0.67 (lumi)) pb for an energy of 7 TeV (in the center of mass frame). This value is consistent with Standard Model's theoretical predictions. Limiting values for the anomalous coupling constants f 4 Z and f 5 Z have been deduced for a confidence ratio of 95%: -0.080 4 Z 5 Z < 0.077. The existence of such couplings would be an indication of new physics beyond the Standard Model. Moreover, the ZZ process in the Standard Model is a background for Higgs searches and have to be well known. Some preliminary studies are performed on the CMS electromagnetic calorimeter. These studies are related to the selective readout system and to the laser monitoring system of the electromagnetic calorimeter. The measurement and the behaviour of the transverse missing energy are also studied in events containing one electroweak boson decaying into electron(s). This study shows that pileup has an important effect on missing transverse energy measurements. Some corrections have to be taken into account to deal with these effects. Conclusions from these analyses contribute to the good understanding of results obtained in the ZZ final states study

Symplectic Synchronization of Lorenz-Stenflo System with Uncertain Chaotic Parameters via Adaptive Control

Directory of Open Access Journals (Sweden)

Cheng-Hsiung Yang

2013-01-01

Full Text Available A new symplectic chaos synchronization of chaotic systems with uncertain chaotic parameters is studied. The traditional chaos synchronizations are special cases of the symplectic chaos synchronization. A sufficient condition is given for the asymptotical stability of the null solution of error dynamics and a parameter difference. The symplectic chaos synchronization with uncertain chaotic parameters may be applied to the design of secure communication systems. Finally, numerical results are studied for symplectic chaos synchronized from two identical Lorenz-Stenflo systems in three different cases.

C P -violation in the two Higgs doublet model: From the LHC to EDMs

Science.gov (United States)

Chen, Chien-Yi; Li, Hao-Lin; Ramsey-Musolf, Michael

2018-01-01

We study the prospective sensitivity to C P -violating two Higgs doublet models from the 14 TeV LHC and future electric dipole moment (EDM) experiments. We concentrate on the search for a resonant heavy Higgs that decays to a Z boson and a SM-like Higgs h , leading to the Z (ℓℓ)h (b b ¯ ) final state. The prospective LHC reach is analyzed using the Boosted Decision Tree method. We illustrate the complementarity between the LHC and low energy EDM measurements and study the dependence of the physics reach on the degree of deviation from the alignment limit. In all cases, we find that there exists a large part of parameter space that is sensitive to both EDMs and LHC searches.

Safe LHC beam commissioning

International Nuclear Information System (INIS)

Uythoven, J.; Schmidt, R.

2007-01-01

Due to the large amount of energy stored in magnets and beams, safety operation of the LHC is essential. The commissioning of the LHC machine protection system will be an integral part of the general LHC commissioning program. A brief overview of the LHC Machine Protection System will be given, identifying the main components: the Beam Interlock System, the Beam Dumping System, the Collimation System, the Beam Loss Monitoring System and the Quench Protection System. An outline is given of the commissioning strategy of these systems during the different commissioning phases of the LHC: without beam, injection and the different phases with stored beam depending on beam intensity and energy. (author)

Study of jet production in ALICE experiment at LHC collider

CERN Document Server

Jangal, Swensy

The jet is one of the probes allowing testing strong interaction theory predictions, QCD, and to extract physical properties from a particular state of nuclear matter : Quark Gluon Plasma (QGP). This PhD work is aimed to show ALICE capacities to measure jets coming from collisions produced at the Large Hadron Collider (LHC). The detection of particles constituting jets, their association with reconstruction algorithms and the construction of observables such as jet pT spectrum of Hump-Backed Plateau is a hard work. We detail these different steps from simulation allowing to estimate jet rates we could expect for our analysis and to evaluate the impact of experimental measure on final observables. We finally present pT spectrum and Hump-Backed Plateau from first p+p collisions at LHC to whom mean corrections have been applied.

Tracking detectors for the sLHC, the LHC upgrade

CERN Document Server

Sadrozinski, Hartmut F W

2005-01-01

The plans for an upgrade of the Large Hadron Collider (LHC) to the Super-LHC (sLHC) are reviewed with special consideration of the environment for the inner tracking system. A straw-man detector upgrade for ATLAS is presented, which is motivated by the varying radiation levels as a function of radius, and choices for detector geometries and technologies are proposed, based on the environmental constraints. A few promising technologies for detectors are discussed, both for sensors and for the associated front-end electronics. On-going research in silicon detectors and in ASIC technologies will be crucial for the success of the upgrade.

Global synchronization of general delayed complex networks with stochastic disturbances

International Nuclear Information System (INIS)

Tu Li-Lan

2011-01-01

In this paper, global synchronization of general delayed complex networks with stochastic disturbances, which is a zero-mean real scalar Wiener process, is investigated. The networks under consideration are continuous-time networks with time-varying delay. Based on the stochastic Lyapunov stability theory, Ito's differential rule and the linear matrix inequality (LMI) optimization technique, several delay-dependent synchronous criteria are established, which guarantee the asymptotical mean-square synchronization of drive networks and response networks with stochastic disturbances. The criteria are expressed in terms of LMI, which can be easily solved using the Matlab LMI Control Toolbox. Finally, two examples show the effectiveness and feasibility of the proposed synchronous conditions. (general)

Quantum gravity effects in black holes at the LHC

International Nuclear Information System (INIS)

Alberghi, G L; Casadio, R; Tronconi, A

2007-01-01

We study possible back-reaction and quantum gravity effects in the evaporation of black holes which could be produced at the LHC through a modification of the Hawking emission. The corrections are phenomenologically taken into account by employing a modified relation between the black hole mass and temperature. The usual assumption that black holes explode around 1 TeV is also released, and the evaporation process is extended to (possibly much) smaller final masses. We show that these effects could be observable for black holes produced with a relatively large mass and should therefore be taken into account when simulating micro-black hole events for the experiments planned at the LHC

Structure identification and adaptive synchronization of uncertain general complex dynamical networks

International Nuclear Information System (INIS)

Xu Yuhua; Zhou Wuneng; Fang Jian'an; Lu Hongqian

2009-01-01

This Letter proposes an approach to identify the topological structure and unknown parameters for uncertain general complex networks simultaneously. By designing effective adaptive controllers, we achieve synchronization between two complex networks. The unknown network topological structure and system parameters of uncertain general complex dynamical networks are identified simultaneously in the process of synchronization. Several useful criteria for synchronization are given. Finally, an illustrative example is presented to demonstrate the application of the theoretical results.

Structure identification and adaptive synchronization of uncertain general complex dynamical networks

Energy Technology Data Exchange (ETDEWEB)

Xu Yuhua, E-mail: yuhuaxu2004@163.co [College of Information Science and Technology, Donghua University, Shanghai 201620 (China) and Department of Maths, Yunyang Teacher' s College, Hubei 442000 (China); Zhou Wuneng, E-mail: wnzhou@163.co [College of Information Science and Technology, Donghua University, Shanghai 201620 (China); Fang Jian' an [College of Information Science and Technology, Donghua University, Shanghai 201620 (China); Lu Hongqian [Shandong Institute of Light Industry, Shandong Jinan 250353 (China)

2009-12-28

This Letter proposes an approach to identify the topological structure and unknown parameters for uncertain general complex networks simultaneously. By designing effective adaptive controllers, we achieve synchronization between two complex networks. The unknown network topological structure and system parameters of uncertain general complex dynamical networks are identified simultaneously in the process of synchronization. Several useful criteria for synchronization are given. Finally, an illustrative example is presented to demonstrate the application of the theoretical results.

Social and Virtual Networks: Evaluating Synchronous Online Interviewing Using Instant Messenger

Science.gov (United States)

Hinchcliffe, Vanessa; Gavin, Helen

2009-01-01

This paper describes an evaluation of the quality and utility of synchronous online interviewing for data collection in social network research. Synchronous online interviews facilitated by Instant Messenger as the communication medium, were undertaken with ten final year university students. Quantitative and qualitative content analysis of…

Gravitinos and hidden supersymmetry at the LHC

Energy Technology Data Exchange (ETDEWEB)

Bobrovskyi, Sergei

2012-08-15

We investigate phenomenological consequences of locally supersymmetric extensions of the Standard Model consistent with primordial nucleosynthesis, leptogenesis and dark matter constraints. An unequivocal prediction of local supersymmetry is the existence of the gravitino, the spin-3/2 superpartner of the graviton. Due to its extremely weak couplings, decays involving the gravitino in the initial or the final state may cause problems in the early universe. One class of models solving the gravitino problem makes the gravitino either the heaviest or the lightest supersymmetric particle (LSP), while predicting a higgsino-like neutralino as the LSP or the next-to-lightest superparticle (NLSP), respectively. In both cases the LHC phenomenology is determined by the higgsino states. The mass degeneracy between the charged and neutral states, together with very heavy colored states, prevent an early discovery at the LHC, especially if one demands a lightest Higgs mass compatible with the recent LHC signal excess. Another class of models, in which the gravitino is also a dark matter candidate, introduces a small violation of R-parity to render the cosmology consistent. In this case, the phenomenology at the LHC is determined by the R-parity violating decays of the NLSP which can be a bino-like or a higgsino-like neutralino or a stau. Using a novel approach to describing bilinear R-parity violation, we compute decay rates of the gravitino and the possible NLSP. Due to a connection between the gravitino and neutralino decay widths, we can predict the neutralino NLSP decay length at the LHC directly from the recent Fermi-LAT results for decaying dark matter searches. The decays of the NLSP in the detectors distort the missing transverse energy (MET) signature, which complicates the searches relying on it, while creating a new secondary vertex signature. We conclude that for gluino and squark masses accessible at the LHC, searches based on secondary vertices can probe values of

Gravitinos and hidden supersymmetry at the LHC

International Nuclear Information System (INIS)

Bobrovskyi, Sergei

2012-08-01

We investigate phenomenological consequences of locally supersymmetric extensions of the Standard Model consistent with primordial nucleosynthesis, leptogenesis and dark matter constraints. An unequivocal prediction of local supersymmetry is the existence of the gravitino, the spin-3/2 superpartner of the graviton. Due to its extremely weak couplings, decays involving the gravitino in the initial or the final state may cause problems in the early universe. One class of models solving the gravitino problem makes the gravitino either the heaviest or the lightest supersymmetric particle (LSP), while predicting a higgsino-like neutralino as the LSP or the next-to-lightest superparticle (NLSP), respectively. In both cases the LHC phenomenology is determined by the higgsino states. The mass degeneracy between the charged and neutral states, together with very heavy colored states, prevent an early discovery at the LHC, especially if one demands a lightest Higgs mass compatible with the recent LHC signal excess. Another class of models, in which the gravitino is also a dark matter candidate, introduces a small violation of R-parity to render the cosmology consistent. In this case, the phenomenology at the LHC is determined by the R-parity violating decays of the NLSP which can be a bino-like or a higgsino-like neutralino or a stau. Using a novel approach to describing bilinear R-parity violation, we compute decay rates of the gravitino and the possible NLSP. Due to a connection between the gravitino and neutralino decay widths, we can predict the neutralino NLSP decay length at the LHC directly from the recent Fermi-LAT results for decaying dark matter searches. The decays of the NLSP in the detectors distort the missing transverse energy (MET) signature, which complicates the searches relying on it, while creating a new secondary vertex signature. We conclude that for gluino and squark masses accessible at the LHC, searches based on secondary vertices can probe values of

Towards LHC experiments

International Nuclear Information System (INIS)

Anon.

1992-01-01

As plans for the LHC proton collider to be built in CERN's 27-kilometre LEP tunnel take shape, interest widens to bring in the experiments exploiting the big machine. The first public presentations of 'expressions of interest' for LHC experiments featured from 5-8 March at Evian-les-Bains on the shore of Lake Geneva, some 50 kilometres from CERN, at the special Towards the LHC Experimental Programme' meeting

Moving Stimuli Facilitate Synchronization But Not Temporal Perception.

Science.gov (United States)

Silva, Susana; Castro, São Luís

2016-01-01

Recent studies have shown that a moving visual stimulus (e.g., a bouncing ball) facilitates synchronization compared to a static stimulus (e.g., a flashing light), and that it can even be as effective as an auditory beep. We asked a group of participants to perform different tasks with four stimulus types: beeps, siren-like sounds, visual flashes (static) and bouncing balls. First, participants performed synchronization with isochronous sequences (stimulus-guided synchronization), followed by a continuation phase in which the stimulus was internally generated (imagery-guided synchronization). Then they performed a perception task, in which they judged whether the final part of a temporal sequence was compatible with the previous beat structure (stimulus-guided perception). Similar to synchronization, an imagery-guided variant was added, in which sequences contained a gap in between (imagery-guided perception). Balls outperformed flashes and matched beeps (powerful ball effect) in stimulus-guided synchronization but not in perception (stimulus- or imagery-guided). In imagery-guided synchronization, performance accuracy decreased for beeps and balls, but not for flashes and sirens. Our findings suggest that the advantages of moving visual stimuli over static ones are grounded in action rather than perception, and they support the hypothesis that the sensorimotor coupling mechanisms for auditory (beeps) and moving visual stimuli (bouncing balls) overlap.

LHC Report: astounding availability

CERN Multimedia

Andrea Apollonio for the LHC team

2016-01-01

The LHC is off to an excellent start in 2016, having already produced triple the luminosity of 2015. An important factor in the impressive performance so far this year is the unprecedented machine availability.   LHC integrated luminosity in 2011, 2012, 2015 and 2016 and the prediction of the 2016 performance foreseen at the start of the year. Following the 2015-2016 end of year shutdown, the LHC restarted beam operation in March 2016. Between the restart and the first technical stop (TS1) in June, the LHC's beam intensity was successively increased, achieving operation with 2040 bunches per beam. The technical stop on 7-8 June was shortened to maximise the time available for luminosity production for the LHC experiments before the summer conferences. Following the technical stop, operation resumed and quickly returned to the performance levels previously achieved. Since then, the LHC has been running steadily with up to 2076 bunches per beam. Since the technical stop, a...

Gaps between jets in double-Pomeron-exchange processes at the LHC

CERN Document Server

Marquet, C; Trzebinski, M; Zlebcik, R

2013-01-01

The possibility to measure jet-gap-jet final states in double-Pomeron-exchange events at the LHC is presented. In the context of the ATLAS experiment with additional forward physics detectors, cross sections for different experimental settings and gap definitions are estimated. This is done in the framework of the Forward Physics Monte Carlo interfaced with a perturbative QCD model that successfully reproduces standard jet-gap-jet cross sections at the Tevatron. The extrapolation to LHC energies follows from the Balitsky-Fadin-Kuraev-Lipatov dynamics, implemented in the model at next-to-leading logarithmic accuracy.

Safety Analysis of the Movable Absorber TCDQ in the LHC Beam Dumping System

CERN Document Server

Filippini, R

2009-01-01

The LHC Beam Dumping System nominally dumps the beam synchronously with the passage of the particle free beam abort gap at the beam dump extraction kickers. In the case of an asynchronous beam dump the TCDQ absorber protects the machine aperture. It is a single sided collimator, positioned close to the beam and it has to follow the beam position and beam size during the energy ramp. This report assesses the different failure scenarios of TCDQ positioning and their likelihood. The failure probability for the two TCDQ systems together is estimated to be 3.6 E-05 (mean value) for one year of LHC operation. This corresponds to a SIL4 safety level, which is considered sufficient. The three dominant failure modes are highlighted. The calculated failure probability refers to scenarios that are generated and developed inside the TCDQ system. Potential failure sources not included are the interaction with external systems: the transmission of the start signal to the PLC from a dedicated timing card and the manual opti...

Chaos synchronization of uncertain Genesio-Tesi chaotic systems with deadzone nonlinearity

International Nuclear Information System (INIS)

Sun, Y.-J.

2009-01-01

In this Letter, the concept of practical synchronization is introduced and the chaos synchronization of uncertain Genesio-Tesi chaotic systems with deadzone nonlinearity is investigated. Based on the time-domain approach, a tracking control is proposed to realize chaos synchronization for the uncertain Genesio-Tesi chaotic systems with deadzone nonlinearity. Moreover, the guaranteed exponential convergence rate and convergence radius can be pre-specified. Finally, a numerical example is provided to illustrate the feasibility and effectiveness of the obtained result.

LHC Report: LHC smashes collision records

CERN Multimedia

Sarah Charley

2016-01-01

The Large Hadron Collider is now producing more than a billion proton-proton collisions per second.   The LHC is colliding protons at a faster rate than ever before: approximately 1 billion times per second. Since April 2016, the LHC has delivered more than 30 inverse femtobarns (fb-1) to both ATLAS and CMS. This means that around 2.4 quadrillion (2.4 million billion) collisions have been seen by each of the experiments this year. The inverse femtobarn is the unit of measurement for integrated luminosity, indicating the cumulative number of potential collisions. This compares with the total of 33.2 fb-1 produced between 2010 and 2015. The unprecedented performance this year is the result of both the incremental increases in collision rate and the sheer amount of time the LHC has been up and running. This comes after a slow start-up in 2015, when scientists and engineers still needed to learn how to operate the machine at a much higher energy. “With more energy, the machine is much more sen...

Some remarks concerning the Cost/Benefit Analysis applied to LHC at CERN

CERN Document Server

Schopper, Herwig

2016-01-01

The cost/benefit analysis originally developed for infrastructures in the economic sector has recently been extended by Florio et al to infrastructures of basic research. As a case study the large accelerator LHC at CERN and its experiments have been selected since as a paradigmatic example of frontier research they offer an excellent case to test the CBA model. It will be shown that in spite of this improved method the LHC poses serious difficulties for such an analysis. Some principle difficulties are due to the special character of scientific projects. Their main result is the production of new basic scientific knowledge whose net social value cannot be easily expressed in monetary terms. Other problems are related to the very strong integration of LHC into the general activities of CERN providing however, interesting observations concerning a new management style for global projects. Finally the mission of CERN (including LHC) is unique since it was founded with two tasks - promote science and bring natio...

Synchronization of switched system and application in communication

International Nuclear Information System (INIS)

Yu Wenwu; Cao Jinde; Yuan Kun

2008-01-01

In this Letter, synchronization of switched system is investigated based on Lyapunov method. A sufficient condition is derived to ensure the synchronization between two switched systems, and a new communication scheme is also proposed based on this. Furthermore, some secure analysis works, such as return map attack and moving average error attack, are also given to show the security of the proposed scheme. Finally, simulation examples are constructed to verify the theoretical analysis and its application for communication

A slice through a prototype LHC bending magnet

CERN Multimedia

Laurent Guiraud

1998-01-01

This slice through a prototype LHC magnet clearly shows the superconducting cable in several blocks around the central hole – the beam pipe in which the LHC’s accelerated beams will travel. Magnet design is crucial to the LHC’s success and this sample is among the first to be built to the final cable configuration.

Synchronization and Control of Linearly Coupled Singular Systems

Directory of Open Access Journals (Sweden)

Fang Qingxiang

2013-01-01

Full Text Available The synchronization and control problem of linearly coupled singular systems is investigated. The uncoupled dynamical behavior at each node is general and can be chaotic or, otherwise the coupling matrix is not assumed to be symmetrical. Some sufficient conditions for globally exponential synchronization are derived based on Lyapunov stability theory. These criteria, which are in terms of linear matrix inequality (LMI, indicate that the left and right eigenvectors corresponding to eigenvalue zero of the coupling matrix play key roles in the stability analysis of the synchronization manifold. The controllers are designed for state feedback control and pinning control, respectively. Finally, a numerical example is provided to illustrate the effectiveness of the proposed conditions.

LHC collimator controls for a safe LHC operation

International Nuclear Information System (INIS)

Redaelli, S.; Assmann, R.; Losito, R.; Donze, M.; Masi, A.

2012-01-01

The Large Hadron Collider (LHC) collimation system is designed to protect the machine against beam losses and consists of 108 collimators, 100 of which are movable, located along the 27 km long ring and in the transfer lines. The cleaning performance and machine protection role of the system depend critically on accurate jaw positioning. A fully redundant control system has been developed to ensure that the collimators dynamically follow optimum settings in all phases of the LHC operational cycle. Jaw positions and collimator gaps are interlocked against dump limits defined redundantly as functions of time, beam energy and the β functions, which describe the focusing property of the beams. In this paper, the architectural choices that guarantee a safe LHC operation are presented. Hardware and software implementations that ensure the required performance are described. (authors)

Searches for new physics in diboson resonances with the ATLAS detector at the LHC

CERN Document Server

Mastrandrea, Paolo; The ATLAS collaboration

2015-01-01

Resonant production of two massive bosons (WW, WZ, ZZ and HH) is a smoking gun signature for physics beyond the Standard Model. Searches for diboson resonances have been performed in final states with different numbers of leptons and jets including fat-jets with jet substructure. This talk highlights ATLAS searches for diboson resonances with LHC Run 1 data. First LHC Run-2 results will be included if available.

Synchronization coupled systems to complex networks

CERN Document Server

Boccaletti, Stefano; del Genio, Charo I; Amann, Andreas

2018-01-01

A modern introduction to synchronization phenomena, this text presents recent discoveries and the current state of research in the field, from low-dimensional systems to complex networks. The book describes some of the main mechanisms of collective behaviour in dynamical systems, including simple coupled systems, chaotic systems, and systems of infinite-dimension. After introducing the reader to the basic concepts of nonlinear dynamics, the book explores the main synchronized states of coupled systems and describes the influence of noise and the occurrence of synchronous motion in multistable and spatially-extended systems. Finally, the authors discuss the underlying principles of collective dynamics on complex networks, providing an understanding of how networked systems are able to function as a whole in order to process information, perform coordinated tasks, and respond collectively to external perturbations. The demonstrations, numerous illustrations and application examples will help advanced graduate s...

Using permanent magnets to boost the dipole field for the High-Energy LHC

CERN Document Server

Zimmermann, Frank

2012-01-01

The High-Energy LHC (HE-LHC) will be a new accelerator in the LHC tunnel based on novel dipole magnets, with a field up to 20 T, which are proposed to be realized by a hybrid-coil design, comprising blocks made from Nb- Ti, Nb$_{3}$Sn and HTS, respectively. Without the HTS the field would be only 15 T. In this note we propose and study the possibility of replacing the inner HTS layer by (weaker) permanent magnets that might contribute a field of 1-2 T, so that the final field would reach 16-17 T. Advantages would be the lower price of permanent magnets compared with HTS magnets and their availability in principle.

The latest from the LHC

CERN Multimedia

2009-01-01

View of the LHC tunnel after the repairs.Three weeks ago vacuum leaks occurred in both Sector 8-1 and 2-3 (See previous update). While the cause and exact locations of the leaks are still unknown, it is suspected that they occurred in both cases from a flexible hose in the liquid helium transport circuits, which vented helium into the vacuum insulation. In Sector 8-1 the leaks occurred while it was being maintained at 80 K in order to perform the resistance measurements on the copper part of the superconducting busbars. Less than 24 hours later a similar leak occurred in Sector 2-3 while it was being warmed from superconducting temperatures to 80 K to perform the busbar resistance measurement. Both leaks happened where the final magnet of the sector (known as Q7) joins the electrical feedbox (called the DFBA). The end vacuum subsectors – a 200-metre stretch of the LHC sealed off by vacuum barriers – will be warmed to room temp...

The ATLAS Tile Calorimeter Performance at LHC

CERN Document Server

Molander, S; The ATLAS collaboration

2013-01-01

The Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of the ATLAS experiment at LHC. The TileCal pays a major role in detecting hadrons, jets, hadronic decays of tau leptons and measuring the missing transverse energy. Due to the very good signal to noise ratio it assists the muon spectrometer in the identification and reconstruction of muons, which are also a tool for the in situ energy scale validation. The results presented here stem from the data collection in dedicated calibration runs, in cosmic rays data-taking and in LHC collisions along 3 years of operation. The uniformity, stability and precision of the energy scale, the time measurement capabilities and the robustness of the performance against pile-up are exposed through the usage of hadronic and muon final states and confirm the design expectations.

LHC Report: The beam is back at the LHC

CERN Multimedia

Reyes Alemany

2015-01-01

A series of sector beam tests paved the way for the start-up of the LHC in 2008 and 2009. These tests and the follow-up of the issues that arose were part of the process that led to a smooth start-up with beam.   Given this experience, sector tests were scheduled to take place several weeks before the 2015 start-up. On the weekend of 6-9 March, beam from the SPS was injected into both LHC injection regions, followed by a first pass through the downstream LHC sectors. For the clockwise LHC beam (called “beam 1”) this meant passing through ALICE and into Sector 2-3, while the anticlockwise beam (called “beam 2”) was threaded through LHCb and all the way from Point 8 to Point 6, where it was extracted by the beam dump kickers onto the beam dump block. The dry runs in the previous weeks were mainly targeted at preparation for the sector tests. The systems tested included: injection, timing, synchronisation and beam instrumentation. The beam interlock ...

Average contraction and synchronization of complex switched networks

International Nuclear Information System (INIS)

Wang Lei; Wang Qingguo

2012-01-01

This paper introduces an average contraction analysis for nonlinear switched systems and applies it to investigating the synchronization of complex networks of coupled systems with switching topology. For a general nonlinear system with a time-dependent switching law, a basic convergence result is presented according to average contraction analysis, and a special case where trajectories of a distributed switched system converge to a linear subspace is then investigated. Synchronization is viewed as the special case with all trajectories approaching the synchronization manifold, and is thus studied for complex networks of coupled oscillators with switching topology. It is shown that the synchronization of a complex switched network can be evaluated by the dynamics of an isolated node, the coupling strength and the time average of the smallest eigenvalue associated with the Laplacians of switching topology and the coupling fashion. Finally, numerical simulations illustrate the effectiveness of the proposed methods. (paper)

New results for exponential synchronization of linearly coupled ordinary differential systems

International Nuclear Information System (INIS)

Tong Ping; Chen Shi-Hua

2017-01-01

This paper investigates the exponential synchronization of linearly coupled ordinary differential systems. The intrinsic nonlinear dynamics may not satisfy the QUAD condition or weak-QUAD condition. First, it gives a new method to analyze the exponential synchronization of the systems. Second, two theorems and their corollaries are proposed for the local or global exponential synchronization of the coupled systems. Finally, an application to the linearly coupled Hopfield neural networks and several simulations are provided for verifying the effectiveness of the theoretical results. (paper)

Mechanical Behaviour of the LHC Cryodipoles

CERN Document Server

Buenaventura, A; Skoczen, Blazej

2000-01-01

The LHC cryodipoles are slender and heavy objects more than 15-m long. The major components of the cryodipole assembly are the 28-tonne cold mass, supported on its three Glass-Fibre-Reinforced-Epoxy support posts and the 4-tonne vacuum vessel. The performance of the LHC depends very much upon the accurate positioning of the dipoles and the beam tubes, in particular to maximise the useful beam apertures. The cryodipoles will be conditioned and measured in surface assembly buildings, then handled and transported to their positions in the tunnel and, finally, aligned. This paper presents the static and dynamic studies of the cryodipole in different configurations. The tests and analyses carried out have led to a thorough understanding of the mechanical behaviour of the cryodipoles. From the static analysis, an hyperstatic supporting system is proposed in order to minimise the systematic deflections and the effects due to changing temperature conditions in the tunnel. The dynamic analysis has shown that the cryod...

LHC Report: Cloudy with sunny spells

CERN Multimedia

Lionel Herblin & Mike Lamont for the LHC team

2015-01-01

The LHC is continuing its 25 ns intensity ramp-up and has now reached 1465 bunches per beam. Performance is reasonable and the experiments have seen some long fills with steadily increasing luminosity delivery rates. Some now familiar issues continue to make life interesting.   The image shows the heat load evolution as measured in specially equipped dipoles. (Image: Giovanni Iadarola). Top frame: energy and intensity. Middle frame: measured heat load in W/m. Bottom frame: heat load normalised to total beam intensity. One of the key challenges of 2015 was always expected to be electron clouds. The two scrubbing runs that were performed in the summer successfully qualified the LHC for up to around 1500 bunches. However, the final phase of the scrubbing, which saw the move from regular 25 ns beam to the doublet beam, proved difficult, and the scrubbing team concluded that the machine was not yet well-enough scrubbed for the doublets to be used effectively. The 25 ...

Search for New Particles in Two-Jet Final States in 7 TeV Proton-Proton Collisions with the ATLAS Detector at the LHC

CERN Document Server

Aad, G.; Abdallah, J.; Abdelalim, A.A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; Abramowicz, H.; Abreu, H.; Acerbi, E.; Acharya, B.S.; Ackers, M.; Adams, D.L.; Addy, T.N.; Adelman, J.; Aderholz, M.; Adomeit, S.; Adorisio, C.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J.A.; Aharrouche, M.; Ahlen, S.P.; Ahles, F.; Ahmad, A.; Ahmed, H.; Ahsan, M.; Aielli, G.; Akdogan, T.; Akesson, T.P.A.; Akimoto, G.; Akimov, A.V.; Aktas, A.; Alam, M.S.; Alam, M.A.; Albrand, S.; Aleksa, M.; Aleksandrov, I.N.; Aleppo, M.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Aliyev, M.; Allport, P.P.; Allwood-Spiers, S.E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, J.; Alviggi, M.G.; Amako, K.; Amaral, P.; Ambrosio, G.; Amelung, C.; Ammosov, V.V.; Amorim, A.; Amoros, G.; Amram, N.; Anastopoulos, C.; Andeen, T.; Anders, C.F.; Anderson, K.J.; Andreazza, A.; Andrei, V.; Andrieux, M-L.; Anduaga, X.S.; Angerami, A.; Anghinolfi, F.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonelli, S.; Antos, J.; Antunovic, B.; Anulli, F.; Aoun, S.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A.T.H.; Archambault, J.P.; Arfaoui, S.; Arguin, J-F.; Argyropoulos, T.; Arik, E.; Arik, M.; Armbruster, A.J.; Arms, K.E.; Armstrong, S.R.; Arnaez, O.; Arnault, C.; Artamonov, A.; Arutinov, D.; Asai, M.; Asai, S.; Asfandiyarov, R.; Ask, S.; Asman, B.; Asner, D.; Asquith, L.; Assamagan, K.; Astbury, A.; Astvatsatourov, A.; Atoian, G.; Aubert, B.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Austin, N.; Avolio, G.; Avramidou, R.; Axen, D.; Ay, C.; Azuelos, G.; Azuma, Y.; Baak, M.A.; Baccaglioni, G.; Bacci, C.; Bach, A.M.; Bachacou, H.; Bachas, K.; Bachy, G.; Backes, M.; Badescu, E.; Bagnaia, P.; Bai, Y.; Bailey, D.C.; Bain, T.; Baines, J.T.; Baker, O.K.; Baker, M.D.; Baker, S; Baltasar Dos Santos Pedrosa, F.; Banas, E.; Banerjee, P.; Banerjee, S.; Banfi, D.; Bangert, A.; Bansal, V.; Baranov, S.P.; Baranov, S.; Barashkou, A.; Barbaro Galtieri, A.; Barber, T.; Barberio, E.L.; Barberis, D.; Barbero, M.; Bardin, D.Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B.M.; Barnett, R.M.; Baroncelli, A.; Barone, M.; Barr, A.J.; Barreiro, F.; Barreiro Guimaraes da Costa, J.; Barrillon, P.; Bartoldus, R.; Bartsch, D.; Bates, R.L.; Batkova, L.; Batley, J.R.; Battaglia, A.; Battistin, M.; Battistoni, G.; Bauer, F.; Bawa, H.S.; Bazalova, M.; Beare, B.; Beau, T.; Beauchemin, P.H.; Beccherle, R.; Bechtle, P.; Beck, G.A.; Beck, H.P.; Beckingham, M.; Becks, K.H.; Beddall, A.J.; Beddall, A.; Bednyakov, V.A.; Bee, C.; Begel, M.; Behar Harpaz, S.; Behera, P.K.; Beimforde, M.; Belanger-Champagne, C.; Belhorma, B.; Bell, P.J.; Bell, W.H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, G.; Bellomo, M.; Belloni, A.; Belotskiy, K.; Beltramello, O.; Ben Ami, S.; Benary, O.; Benchekroun, D.; Benchouk, C.; Bendel, M.; Benedict, B.H.; Benekos, N.; Benhammou, Y.; Benincasa, G.P.; Benjamin, D.P.; Benoit, M.; Bensinger, J.R.; Benslama, K.; Bentvelsen, S.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernardet, K.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertin, A.; Bertinelli, F.; Bertolucci, F.; Bertolucci, S.; Besana, M.I.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R.M.; Bianco, M.; Biebel, O.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Binder, M.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bischof, R.; Bitenc, U.; Black, K.M.; Blair, R.E.; Blanchard, J-B; Blanchot, G.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Boaretto, C.; Bobbink, G.J.; Bocci, A.; Bocian, D.; Bock, R.; Boddy, C.R.; Boehler, M.; Boek, J.; Boelaert, N.; Boser, S.; Bogaerts, J.A.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Bondarenko, V.G.; Bondioli, M.; Boonekamp, M.; Boorman, G.; Booth, C.N.; Booth, P.; Booth, J.R.A.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borroni, S.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Botterill, D.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E.V.; Boulahouache, C.; Bourdarios, C.; Boveia, A.; Boyd, J.; Boyko, I.R.; Bozhko, N.I.; Bozovic-Jelisavcic, I.; Braccini, S.; Bracinik, J.; Braem, A.; Brambilla, E.; Branchini, P.; Brandenburg, G.W.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J.E.; Braun, H.M.; Brelier, B.; Bremer, J.; Brenner, R.; Bressler, S.; Breton, D.; Brett, N.D.; Bright-Thomas, P.G.; Britton, D.; Brochu, F.M.; Brock, I.; Brock, R.; Brodbeck, T.J.; Brodet, E.; Broggi, F.; Bromberg, C.; Brooijmans, G.; Brooks, W.K.; Brown, G.; Brubaker, E.; Bruckman de Renstrom, P.A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Buanes, T.; Bucci, F.; Buchanan, J.; Buchanan, N.J.; Buchholz, P.; Buckingham, R.M.; Buckley, A.G.; Budagov, I.A.; Budick, B.; Buscher, V.; Bugge, L.; Buira-Clark, D.; Buis, E.J.; Bulekov, O.; Bunse, M.; Buran, T.; Burckhart, H.; Burdin, S.; Burgess, T.; Burke, S.; Busato, E.; Bussey, P.; Buszello, C.P.; Butin, F.; Butler, B.; Butler, J.M.; Buttar, C.M.; Butterworth, J.M.; Byatt, T.; Caballero, J.; Cabrera Urban, S.; Caccia, M.; Caforio, D.; Cakir, O.; Calafiura, P.; Calderini, G.; Calfayan, P.; Calkins, R.; Caloba, L.P.; Caloi, R.; Calvet, D.; Camard, A.; Camarri, P.; Cambiaghi, M.; Cameron, D.; Cammin, J.; Campana, S.; Campanelli, M.; Canale, V.; Canelli, F.; Canepa, A.; Cantero, J.; Capasso, L.; Capeans Garrido, M.D.M.; Caprini, I.; Caprini, M.; Caprio, M.; Capriotti, D.; Capua, M.; Caputo, R.; Caramarcu, C.; Cardarelli, R.; Carli, T.; Carlino, G.; Carminati, L.; Caron, B.; Caron, S.; Carpentieri, C.; Carrillo Montoya, G.D.; Carron Montero, S.; Carter, A.A.; Carter, J.R.; Carvalho, J.; Casadei, D.; Casado, M.P.; Cascella, M.; Caso, C.; Castaneda Hernandez, A.M.; Castaneda-Miranda, E.; Castillo Gimenez, V.; Castro, N.F.; Cataldi, G.; Cataneo, F.; Catinaccio, A.; Catmore, J.R.; Cattai, A.; Cattani, G.; Caughron, S.; Cauz, D.; Cavallari, A.; Cavalleri, P.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Cazzato, A.; Ceradini, F.; Cerna, C.; Cerqueira, A.S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cervetto, M.; Cetin, S.A.; Cevenini, F.; Chafaq, A.; Chakraborty, D.; Chan, K.; Chapman, J.D.; Chapman, J.W.; Chareyre, E.; Charlton, D.G.; Chavda, V.; Cheatham, S.; Chekanov, S.; Chekulaev, S.V.; Chelkov, G.A.; Chen, H.; Chen, L.; Chen, S.; Chen, T.; Chen, X.; Cheng, S.; Cheplakov, A.; Chepurnov, V.F.; Cherkaoui El Moursli, R.; Tcherniatine, V.; Chesneanu, D.; Cheu, E.; Cheung, S.L.; Chevalier, L.; Chevallier, F.; Chiarella, V.; Chiefari, G.; Chikovani, L.; Childers, J.T.; Chilingarov, A.; Chiodini, G.; Chizhov, M.V.; Choudalakis, G.; Chouridou, S.; Christidi, I.A.; Christov, A.; Chromek-Burckhart, D.; Chu, M.L.; Chudoba, J.; Ciapetti, G.; Ciftci, A.K.; Ciftci, R.; Cinca, D.; Cindro, V.; Ciobotaru, M.D.; Ciocca, C.; Ciocio, A.; Cirilli, M.; Citterio, M.; Clark, A.; Clark, P.J.; Cleland, W.; Clemens, J.C.; Clement, B.; Clement, C.; Clifft, R.W.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coe, P.; Coelli, S.; Coggeshall, J.; Cogneras, E.; Cojocaru, C.D.; Colas, J.; Cole, B.; Colijn, A.P.; Collard, C.; Collins, N.J.; Collins-Tooth, C.; Collot, J.; Colon, G.; Coluccia, R.; Comune, G.; Conde Muino, P.; Coniavitis, E.; Conidi, M.C.; Consonni, M.; Constantinescu, S.; Conta, C.; Conventi, F.; Cook, J.; Cooke, M.; Cooper, B.D.; Cooper-Sarkar, A.M.; Cooper-Smith, N.J.; Copic, K.; Cornelissen, T.; Corradi, M.; Correard, S.; Corriveau, F.; Corso-Radu, A.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M.J.; Costanzo, D.; Costin, T.; Cote, D.; Coura Torres, R.; Courneyea, L.; Cowan, G.; Cowden, C.; Cox, B.E.; Cranmer, K.; Cranshaw, J.; Cristinziani, M.; Crosetti, G.; Crupi, R.; Crepe-Renaudin, S.; Cuenca Almenar, C.; Cuhadar Donszelmann, T.; Cuneo, S.; Curatolo, M.; Curtis, C.J.; Cwetanski, P.; Czirr, H.; Czyczula, Z.; D'Auria, S.; D'Onofrio, M.; D'Orazio, A.; Da Rocha Gesualdi Mello, A.; Da Silva, P.V.M.; Da Via, C; Dabrowski, W.; Dahlhoff, A.; Dai, T.; Dallapiccola, C.; Dallison, S.J.; Dalmau, J.; Daly, C.H.; Dam, M.; Dameri, M.; Danielsson, H.O.; Dankers, R.; Dannheim, D.; Dao, V.; Darbo, G.; Darlea, G.L.; Daum, C.; Dauvergne, J.P.; Davey, W.; Davidek, T.; Davidson, N.; Davidson, R.; Davies, M.; Davison, A.R.; Dawe, E.; Dawson, I.; Dawson, J.W.; Daya, R.K.; De, K.; de Asmundis, R.; De Castro, S.; De Castro Faria Salgado, P.E.; De Cecco, S.; de Graat, J.; De Groot, N.; de Jong, P.; De La Cruz-Burelo, E.; De La Taille, C.; De Lotto, B.; De Mora, L.; De Nooij, L.; De Oliveira Branco, M.; De Pedis, D.; de Saintignon, P.; De Salvo, A.; De Sanctis, U.; De Santo, A.; De Vivie De Regie, J.B.; De Zorzi, G.; Dean, S.; Dedes, G.; Dedovich, D.V.; Defay, P.O.; Degenhardt, J.; Dehchar, M.; Deile, M.; Del Papa, C.; Del Peso, J.; Del Prete, T.; Dell'Acqua, A.; Dell'Asta, L.; Della Pietra, M.; della Volpe, D.; Delmastro, M.; Delpierre, P.; Delruelle, N.; Delsart, P.A.; Deluca, C.; Demers, S.; Demichev, M.; Demirkoz, B.; Deng, J.; Deng, W.; Denisov, S.P.; Dennis, C.; Derkaoui, J.E.; Derue, F.; Dervan, P.; Desch, K.; Deviveiros, P.O.; Dewhurst, A.; DeWilde, B.; Dhaliwal, S.; Dhullipudi, R.; Di Ciaccio, A.; Di Ciaccio, L.; Di Domenico, A.; Di Girolamo, A.; Di Girolamo, B.; Di Luise, S.; Di Mattia, A.; Di Nardo, R.; Di Simone, A.; Di Sipio, R.; Diaz, M.A.; Diaz Gomez, M.M.; Diblen, F.; Diehl, E.B.; Dietl, H.; Dietrich, J.; Dietzsch, T.A.; Diglio, S.; Dindar Yagci, K.; Dingfelder, J.; Dionisi, C.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djilkibaev, R.; Djobava, T.; do Vale, M.A.B.; Do Valle Wemans, A.; Doan, T.K.O.; Dobbs, M.; Dobinson, R.; Dobos, D.; Dobson, E.; Dobson, M.; Dodd, J.; Dogan, O.B.; Doglioni, C.; Doherty, T.; Doi, Y.; Dolejsi, J.; Dolenc, I.; Dolezal, Z.; Dolgoshein, B.A.; Dohmae, T.; Donega, M.; Donini, J.; Dopke, J.; Doria, A.; Dos Anjos, A.; Dosil, M.; Dotti, A.; Dova, M.T.; Dowell, J.D.; Doxiadis, A.; Doyle, A.T.; Drasal, Z.; Drees, J.; Dressnandt, N.; Drevermann, H.; Driouichi, C.; Dris, M.; Drohan, J.G.; Dubbert, J.; Dubbs, T.; Dube, S.; Duchovni, E.; Duckeck, G.; Dudarev, A.; Dudziak, F.; Duhrssen, M.; Duerdoth, I.P.; Duflot, L.; Dufour, M-A.; Dunford, M.; Duran Yildiz, H.; Dushkin, A.; Duxfield, R.; Dwuznik, M.; Dydak, F.; Dzahini, D.; Duren, M.; Ebenstein, W.L.; Ebke, J.; Eckert, S.; Eckweiler, S.; Edmonds, K.; Edwards, C.A.; Efthymiopoulos, I.; Egorov, K.; Ehrenfeld, W.; Ehrich, T.; Eifert, T.; Eigen, G.; Einsweiler, K.; Eisenhandler, E.; Ekelof, T.; El Kacimi, M.; Ellert, M.; Elles, S.; Ellinghaus, F.; Ellis, K.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Ely, R.; Emeliyanov, D.; Engelmann, R.; Engl, A.; Epp, B.; Eppig, A.; Erdmann, J.; Ereditato, A.; Eremin, V.; Eriksson, D.; Ermoline, I.; Ernst, J.; Ernst, M.; Ernwein, J.; Errede, D.; Errede, S.; Ertel, E.; Escalier, M.; Escobar, C.; Espinal Curull, X.; Esposito, B.; Etienne, F.; Etienvre, A.I.; Etzion, E.; Evans, H.; Evdokimov, V.N.; Fabbri, L.; Fabre, C.; Facius, K.; Fakhrutdinov, R.M.; Falciano, S.; Falou, A.C.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farley, J.; Farooque, T.; Farrington, S.M.; Farthouat, P.; Fasching, D.; Fassnacht, P.; Fassouliotis, D.; Fatholahzadeh, B.; Fayard, L.; Fazio, S.; Febbraro, R.; Federic, P.; Fedin, O.L.; Fedorko, I.; Fedorko, W.; Fehling-Kaschek, M.; Feligioni, L.; Felzmann, C.U.; Feng, C.; Feng, E.J.; Fenyuk, A.B.; Ferencei, J.; Ferguson, D.; Ferland, J.; Fernandes, B.; Fernando, W.; Ferrag, S.; Ferrando, J.; Ferrara, V.; Ferrari, A.; Ferrari, P.; Ferrari, R.; Ferrer, A.; Ferrer, M.L.; Ferrere, D.; Ferretti, C.; Ferretto Parodi, A.; Ferro, F.; Fiascaris, M.; Fiedler, F.; Filipcic, A.; Filippas, A.; Filthaut, F.; Fincke-Keeler, M.; Fiolhais, M.C.N.; Fiorini, L.; Firan, A.; Fischer, G.; Fischer, P.; Fisher, M.J.; Fisher, S.M.; Flammer, J.; Flechl, M.; Fleck, I.; Fleckner, J.; Fleischmann, P.; Fleischmann, S.; Flick, T.; Flores Castillo, L.R.; Flowerdew, M.J.; Fohlisch, F.; Fokitis, M.; Fonseca Martin, T.; Fopma, J.; Forbush, D.A.; Formica, A.; Forti, A.; Fortin, D.; Foster, J.M.; Fournier, D.; Foussat, A.; Fowler, A.J.; Fowler, K.; Fox, H.; Francavilla, P.; Franchino, S.; Francis, D.; Franklin, M.; Franz, S.; Fraternali, M.; Fratina, S.; Freestone, J.; French, S.T.; Froeschl, R.; Froidevaux, D.; Frost, J.A.; Fukunaga, C.; Fullana Torregrosa, E.; Fuster, J.; Gabaldon, C.; Gabizon, O.; Gadfort, T.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Galea, C.; Gallas, E.J.; Gallas, M.V.; Gallo, V.; Gallop, B.J.; Gallus, P.; Galyaev, E.; Gan, K.K.; Gao, Y.S.; Gapienko, V.A.; Gaponenko, A.; Garcia-Sciveres, M.; Garcia, C.; Garcia Navarro, J.E.; Gardner, R.W.; Garelli, N.; Garitaonandia, H.; Garonne, V.; Garvey, J.; Gatti, C.; Gaudio, G.; Gaumer, O.; Gautard, V.; Gauzzi, P.; Gavrilenko, I.L.; Gay, C.; Gaycken, G.; Gayde, J-C.; Gazis, E.N.; Ge, P.; Gee, C.N.P.; Geich-Gimbel, Ch.; Gellerstedt, K.; Gemme, C.; Genest, M.H.; Gentile, S.; Georgatos, F.; George, S.; Gerlach, P.; Gershon, A.; Geweniger, C.; Ghazlane, H.; Ghez, P.; Ghodbane, N.; Giacobbe, B.; Giagu, S.; Giakoumopoulou, V.; Giangiobbe, V.; Gianotti, F.; Gibbard, B.; Gibson, A.; Gibson, S.M.; Gieraltowski, G.F.; Gilbert, L.M.; Gilchriese, M.; Gildemeister, O.; Gilewsky, V.; Gillberg, D.; Gillman, A.R.; Gingrich, D.M.; Ginzburg, J.; Giokaris, N.; Giordani, M.P.; Giordano, R.; Giorgi, F.M.; Giovannini, P.; Giraud, P.F.; Girtler, P.; Giugni, D.; Giusti, P.; Gjelsten, B.K.; Gladilin, L.K.; Glasman, C.; Glatzer, J; Glazov, A.; Glitza, K.W.; Glonti, G.L.; Gnanvo, K.G.; Godfrey, J.; Godlewski, J.; Goebel, M.; Gopfert, T.; Goeringer, C.; Gossling, C.; Gottfert, T.; Goggi, V.; Goldfarb, S.; Goldin, D.; Golling, T.; Gollub, N.P.; Golovnia, S.N.; Gomes, A.; Gomez Fajardo, L.S.; Goncalo, R.; Gonella, L.; Gong, C.; Gonidec, A.; Gonzalez, S.; Gonzalez de la Hoz, S.; Gonzalez Silva, M.L.; Gonzalez-Pineiro, B.; Gonzalez-Sevilla, S.; Goodson, J.J.; Goossens, L.; Gorbounov, P.A.; Gordon, H.A.; Gorelov, I.; Gorfine, G.; Gorini, B.; Gorini, E.; Gorisek, A.; Gornicki, E.; Gorokhov, S.A.; Gorski, B.T.; Goryachev, V.N.; Gosdzik, B.; Gosselink, M.; Gostkin, M.I.; Gouanere, M.; Gough Eschrich, I.; Gouighri, M.; Goujdami, D.; Goulette, M.P.; Goussiou, A.G.; Goy, C.; Grabowska-Bold, I.; Grabski, V.; Grafstrom, P.; Grah, C.; Grahn, K-J.; Grancagnolo, F.; Grancagnolo, S.; Grassi, V.; Gratchev, V.; Grau, N.; Gray, H.M.; Gray, J.A.; Graziani, E.; Grebenyuk, O.G.; Green, B.; Greenfield, D.; Greenshaw, T.; Greenwood, Z.D.; Gregor, I.M.; Grenier, P.; Grewal, A.; Griesmayer, E.; Griffiths, J.; Grigalashvili, N.; Grillo, A.A.; Grimm, K.; Grinstein, S.; Gris, P.L.Y.; Grishkevich, Y.V.; Grivaz, J.F.; Groer, L.S.; Grognuz, J.; Groh, M.; Groll, M.; Gross, E.; Grosse-Knetter, J.; Groth-Jensen, J.; Gruwe, M.; Grybel, K.; Guarino, V.J.; Guicheney, C.; Guida, A.; Guillemin, T.; Guler, H.; Gunther, J.; Guo, B.; Gupta, A.; Gusakov, Y.; Gushchin, V.N.; Gutierrez, A.; Gutierrez, P.; Guttman, N.; Gutzwiller, O.; Guyot, C.; Gwenlan, C.; Gwilliam, C.B.; Haas, A.; Haas, S.; Haber, C.; Haboubi, G.; Hackenburg, R.; Hadavand, H.K.; Hadley, D.R.; Haeberli, C.; Haefner, P.; Hartel, R.; Hahn, F.; Haider, S.; Hajduk, Z.; Hakobyan, H.; Haller, J.; Hallewell, G.D.; Hamacher, K.; Hamilton, A.; Hamilton, S.; Han, H.; Han, L.; Hanagaki, K.; Hance, M.; Handel, C.; Hanke, P.; Hansen, C.J.; Hansen, J.R.; Hansen, J.B.; Hansen, J.D.; Hansen, P.H.; Hansl-Kozanecka, T.; Hansson, P.; Hara, K.; Hare, G.A.; Harenberg, T.; Harper, R.; Harrington, R.D.; Harris, O.M.; Harrison, K; Hart, J.C.; Hartert, J.; Hartjes, F.; Haruyama, T.; Harvey, A.; Hasegawa, S.; Hasegawa, Y.; Hashemi, K.; Hassani, S.; Hatch, M.; Hauff, D.; Haug, S.; Hauschild, M.; Hauser, R.; Havranek, M.; Hawes, B.M.; Hawkes, C.M.; Hawkings, R.J.; Hawkins, D.; Hayakawa, T.; Hayward, H.S.; Haywood, S.J.; Hazen, E.; He, M.; Head, S.J.; Hedberg, V.; Heelan, L.; Heim, S.; Heinemann, B.; Heinemann, F.E.W.; Heisterkamp, S.; Helary, L.; Heldmann, M.; Heller, M.; Hellman, S.; Helsens, C.; Hemperek, T.; Henderson, R.C.W.; Hendriks, P.J.; Henke, M.; Henrichs, A.; Henriques Correia, A.M.; Henrot-Versille, S.; Henry-Couannier, F.; Hensel, C.; Henss, T.; Hernandez Jimenez, Y.; Hershenhorn, A.D.; Herten, G.; Hertenberger, R.; Hervas, L.; Hessey, N.P.; Hidvegi, A.; Higon-Rodriguez, E.; Hill, D.; Hill, J.C.; Hill, N.; Hiller, K.H.; Hillert, S.; Hillier, S.J.; Hinchliffe, I.; Hindson, D.; Hines, E.; Hirose, M.; Hirsch, F.; Hirschbuehl, D.; Hobbs, J.; Hod, N.; Hodgkinson, M.C.; Hodgson, P.; Hoecker, A.; Hoeferkamp, M.R.; Hoffman, J.; Hoffmann, D.; Hohlfeld, M.; Holder, M.; Hollins, T.I.; Hollyman, G.; Holmes, A.; Holmgren, S.O.; Holy, T.; Holzbauer, J.L.; Homer, R.J.; Homma, Y.; Horazdovsky, T.; Horn, C.; Horner, S.; Horvat, S.; Hostachy, J-Y.; Hott, T.; Hou, S.; Houlden, M.A.; Hoummada, A.; Howell, D.F.; Hrivnac, J.; Hruska, I.; Hryn'ova, T.; Hsu, P.J.; Hsu, S.C.; Huang, G.S.; Hubacek, Z.; Hubaut, F.; Huegging, F.; Huffman, T.B.; Hughes, E.W.; Hughes, G.; Hughes-Jones, R.E.; Huhtinen, M.; Hurst, P.; Hurwitz, M.; Husemann, U.; Huseynov, N.; Huston, J.; Huth, J.; Iacobucci, G.; Iakovidis, G.; Ibbotson, M.; Ibragimov, I.; Ichimiya, R.; Iconomidou-Fayard, L.; Idarraga, J.; Idzik, M.; Iengo, P.; Igonkina, O.; Ikegami, Y.; Ikeno, M.; Ilchenko, Y.; Iliadis, D.; Imbault, D.; Imhaeuser, M.; Imori, M.; Ince, T.; Inigo-Golfin, J.; Ioannou, P.; Iodice, M.; Ionescu, G.; Irles Quiles, A.; Ishii, K.; Ishikawa, A.; Ishino, M.; Ishmukhametov, R.; Isobe, T.; Issakov, V.; Issever, C.; Istin, S.; Itoh, Y.; Ivashin, A.V.; Iwanski, W.; Iwasaki, H.; Izen, J.M.; Izzo, V.; Jackson, B.; Jackson, J.N.; Jackson, P.; Jaekel, M.R.; Jahoda, M.; Jain, V.; Jakobs, K.; Jakobsen, S.; Jakubek, J.; Jana, D.K.; Jankowski, E.; Jansen, E.; Jantsch, A.; Janus, M.; Jared, R.C.; Jarlskog, G.; Jeanty, L.; Jelen, K.; Jen-La Plante, I.; Jenni, P.; Jeremie, A.; Jez, P.; Jezequel, S.; Ji, H.; Ji, W.; Jia, J.; Jiang, Y.; Jimenez Belenguer, M.; Jin, G.; Jin, S.; Jinnouchi, O.; Joffe, D.; Johansen, L.G.; Johansen, M.; Johansson, K.E.; Johansson, P.; Johnert, S.; Johns, K.A.; Jon-And, K.; Jones, G.; Jones, M.; Jones, R.W.L.; Jones, T.W.; Jones, T.J.; Jonsson, O.; Joo, K.K.; Joos, D.; Joram, C.; Jorge, P.M.; Jorgensen, S.; Joseph, J.; Juranek, V.; Jussel, P.; Kabachenko, V.V.; Kabana, S.; Kaci, M.; Kaczmarska, A.; Kadlecik, P.; Kado, M.; Kagan, H.; Kagan, M.; Kaiser, S.; Kajomovitz, E.; Kalinin, S.; Kalinovskaya, L.V.; Kama, S.; Kanaya, N.; Kaneda, M.; Kantserov, V.A.; Kanzaki, J.; Kaplan, B.; Kapliy, A.; Kaplon, J.; Kar, D.; Karagounis, M.; Karagoz, M.; Karnevskiy, M.; Karr, K.; Kartvelishvili, V.; Karyukhin, A.N.; Kashif, L.; Kasmi, A.; Kass, R.D.; Kastanas, A.; Kastoryano, M.; Kataoka, M.; Kataoka, Y.; Katsoufis, E.; Katzy, J.; Kaushik, V.; Kawagoe, K.; Kawamoto, T.; Kawamura, G.; Kayl, M.S.; Kayumov, F.; Kazanin, V.A.; Kazarinov, M.Y.; Kazi, S.I.; Keates, J.R.; Keeler, R.; Keener, P.T.; Kehoe, R.; Keil, M.; Kekelidze, G.D.; Kelly, M.; Kennedy, J.; Kenney, C.J.; Kenyon, M.; Kepka, O.; Kerschen, N.; Kersevan, B.P.; Kersten, S.; Kessoku, K.; Ketterer, C.; Khakzad, M.; Khalil-zada, F.; Khandanyan, H.; Khanov, A.; Kharchenko, D.; Khodinov, A.; Kholodenko, A.G.; Khomich, A.; Khoriauli, G.; Khovanskiy, N.; Khovanskiy, V.; Khramov, E.; Khubua, J.; Kilvington, G.; Kim, H.; Kim, M.S.; Kim, P.C.; Kim, S.H.; Kimura, N.; Kind, O.; Kind, P.; King, B.T.; King, M.; Kirk, J.; Kirsch, G.P.; Kirsch, L.E.; Kiryunin, A.E.; Kisielewska, D.; Kisielewski, B.; Kittelmann, T.; Kiver, A.M.; Kiyamura, H.; Kladiva, E.; Klaiber-Lodewigs, J.; Klein, M.; Klein, U.; Kleinknecht, K.; Klemetti, M.; Klier, A.; Klimentov, A.; Klingenberg, R.; Klinkby, E.B.; Klioutchnikova, T.; Klok, P.F.; Klous, S.; Kluge, E.E.; Kluge, T.; Kluit, P.; Kluth, S.; Knecht, N.S.; Kneringer, E.; Knobloch, J.; Ko, B.R.; Kobayashi, T.; Kobel, M.; Koblitz, B.; Kocian, M.; Kocnar, A.; Kodys, P.; Koneke, K.; Konig, A.C.; Koenig, S.; Konig, S.; Kopke, L.; Koetsveld, F.; Koevesarki, P.; Koffas, T.; Koffeman, E.; Kohn, F.; Kohout, Z.; Kohriki, T.; Koi, T.; Kokott, T.; Kolachev, G.M.; Kolanoski, H.; Kolesnikov, V.; Koletsou, I.; Koll, J.; Kollar, D.; Kollefrath, M.; Kolos, S.; Kolya, S.D.; Komar, A.A.; Komaragiri, J.R.; Kondo, T.; Kono, T.; Kononov, A.I.; Konoplich, R.; Konovalov, S.P.; Konstantinidis, N.; Kootz, A.; Koperny, S.; Kopikov, S.V.; Korcyl, K.; Kordas, K.; Koreshev, V.; Korn, A.; Korol, A.; Korolkov, I.; Korolkova, E.V.; Korotkov, V.A.; Kortner, O.; Kostka, P.; Kostyukhin, V.V.; Kotamaki, M.J.; Kotov, S.; Kotov, V.M.; Kotov, K.Y.; Kourkoumelis, C.; Koutsman, A.; Kowalewski, R.; Kowalski, H.; Kowalski, T.Z.; Kozanecki, W.; Kozhin, A.S.; Kral, V.; Kramarenko, V.A.; Kramberger, G.; Krasel, O.; Krasny, M.W.; Krasznahorkay, A.; Kraus, J.; Kreisel, A.; Krejci, F.; Kretzschmar, J.; Krieger, N.; Krieger, P.; Krobath, G.; Kroeninger, K.; Kroha, H.; Kroll, J.; Kroseberg, J.; Krstic, J.; Kruchonak, U.; Kruger, H.; Krumshteyn, Z.V.; Kruth, A.; Kubota, T.; Kuehn, S.; Kugel, A.; Kuhl, T.; Kuhn, D.; Kukhtin, V.; Kulchitsky, Y.; Kuleshov, S.; Kummer, C.; Kuna, M.; Kundu, N.; Kunkle, J.; Kupco, A.; Kurashige, H.; Kurata, M.; Kurchaninov, L.L.; Kurochkin, Y.A.; Kus, V.; Kuykendall, W.; Kuze, M.; Kuzhir, P.; Kvasnicka, O.; Kwee, R.; La Rosa, A.; La Rotonda, L.; Labarga, L.; Labbe, J.; Lacasta, C.; Lacava, F.; Lacker, H.; Lacour, D.; Lacuesta, V.R.; Ladygin, E.; Lafaye, R.; Laforge, B.; Lagouri, T.; Lai, S.; Lamanna, M.; Lambacher, M.; Lampen, C.L.; Lampl, W.; Lancon, E.; Landgraf, U.; Landon, M.P.J.; Landsman, H.; Lane, J.L.; Lange, C.; Lankford, A.J.; Lanni, F.; Lantzsch, K.; Lanza, A.; Lapin, V.V.; Laplace, S.; Lapoire, C.; Laporte, J.F.; Lari, T.; Larionov, A.V.; Larner, A.; Lasseur, C.; Lassnig, M.; Lau, W.; Laurelli, P.; Lavorato, A.; Lavrijsen, W.; Laycock, P.; Lazarev, A.B.; Lazzaro, A.; Le Dortz, O.; Le Guirriec, E.; Le Maner, C.; Le Menedeu, E.; Le Vine, M.; Leahu, M.; Lebedev, A.; Lebel, C.; Lechowski, M.; LeCompte, T.; Ledroit-Guillon, F.; Lee, H.; Lee, J.S.H.; Lee, S.C.; Lefebvre, M.; Legendre, M.; Leger, A.; LeGeyt, B.C.; Legger, F.; Leggett, C.; Lehmacher, M.; Lehmann Miotto, G.; Lehto, M.; Lei, X.; Leitner, R.; Lellouch, D.; Lellouch, J.; Leltchouk, M.; Lendermann, V.; Leney, K.J.C.; Lenz, T.; Lenzen, G.; Lenzi, B.; Leonhardt, K.; Lepidis, J.; Leroy, C.; Lessard, J-R.; Lesser, J.; Lester, C.G.; Leung Fook Cheong, A.; Leveque, J.; Levin, D.; Levinson, L.J.; Levitski, M.S.; Lewandowska, M.; Leyton, M.; Li, H.; Li, X.; Liang, Z.; Liang, Z.; Liberti, B.; Lichard, P.; Lichtnecker, M.; Lie, K.; Liebig, W.; Lifshitz, R.; Lilley, J.N.; Lim, H.; Limosani, A.; Limper, M.; Lin, S.C.; Linde, F.; Linnemann, J.T.; Lipeles, E.; Lipinsky, L.; Lipniacka, A.; Liss, T.M.; Lissauer, D.; Lister, A.; Litke, A.M.; Liu, C.; Liu, D.; Liu, H.; Liu, J.B.; Liu, M.; Liu, S.; Liu, T.; Liu, Y.; Livan, M.; Livermore, S.S.A.; Lleres, A.; Lloyd, S.L.; Lobodzinska, E.; Loch, P.; Lockman, W.S.; Lockwitz, S.; Loddenkoetter, T.; Loebinger, F.K.; Loginov, A.; Loh, C.W.; Lohse, T.; Lohwasser, K.; Lokajicek, M.; Loken, J.; Long, R.E.; Lopes, L.; Lopez Mateos, D.; Losada, M.; Loscutoff, P.; Losty, M.J.; Lou, X.; Lounis, A.; Loureiro, K.F.; Lovas, L.; Love, J.; Love, P.A.; Lowe, A.J.; Lu, F.; Lu, J.; Lu, L.; Lubatti, H.J.; Luci, C.; Lucotte, A.; Ludwig, A.; Ludwig, D.; Ludwig, I.; Ludwig, J.; Luehring, F.; Luijckx, G.; Lumb, D.; Luminari, L.; Lund, E.; Lund-Jensen, B.; Lundberg, B.; Lundberg, J.; Lundquist, J.; Lupi, A.; Lutz, G.; Lynn, D.; Lynn, J.; Lys, J.; Lytken, E.; Ma, H.; Ma, L.L.; Maass en, M.; Macana Goia, J.A.; Maccarrone, G.; Macchiolo, A.; Macek, B.; Machado Miguens, J.; Macina, D.; Mackeprang, R.; MacQueen, D.; Madaras, R.J.; Mader, W.F.; Maenner, R.; Maeno, T.; Mattig, P.; Mattig, S.; Magalhaes Martins, P.J.; Magnoni, L.; Magradze, E.; Magrath, C.A.; Mahalalel, Y.; Mahboubi, K.; Mahmood, A.; Mahout, G.; Maiani, C.; Maidantchik, C.; Maio, A.; Majewski, S.; Makida, Y.; Makouski, M.; Makovec, N.; Mal, P.; Malecki, Pa.; Malecki, P.; Maleev, V.P.; Malek, F.; Mallik, U.; Malon, D.; Maltezos, S.; Malyshev, V.; Malyukov, S.; Mambelli, M.; Mameghani, R.; Mamuzic, J.; Manabe, A.; Manara, A.; Mandelli, L.; Mandic, I.; Mandrysch, R.; Maneira, J.; Mangeard, P.S.; Mangin-Brinet, M.; Manjavidze, I.D.; Mann, A.; Mann, W.A.; Manning, P.M.; Manousakis-Katsikakis, A.; Mansoulie, B.; Manz, A.; Mapelli, A.; Mapelli, L.; March, L.; Marchand, J.F.; Marchese, F.; Marchesotti, M.; Marchiori, G.; Marcisovsky, M.; Marin, A.; Marino, C.P.; Marroquim, F.; Marshall, R.; Marshall, Z.; Martens, F.K.; Marti-Garcia, S.; Martin, A.J.; Martin, A.J.; Martin, B.; Martin, B.; Martin, F.F.; Martin, J.P.; Martin, Ph.; Martin, T.A.; Martin dit Latour, B.; Martinez, M.; Martinez Outschoorn, V.; Martini, A.; Martyniuk, A.C.; Marzano, F.; Marzin, A.; Masetti, L.; Mashimo, T.; Mashinistov, R.; Masik, J.; Maslennikov, A.L.; Mass, M.; Massa, I.; Massaro, G.; Massol, N.; Mastroberardino, A.; Masubuchi, T.; Mathes, M.; Matricon, P.; Matsumoto, H.; Matsunaga, H.; Matsushita, T.; Mattravers, C.; Maugain, J.M.; Maxfield, S.J.; May, E.N.; Mayer, J.K.; Mayne, A.; Mazini, R.; Mazur, M.; Mazzanti, M.; Mazzoni, E.; Mc Donald, J.; Mc Kee, S.P.; McCarn, A.; McCarthy, R.L.; McCarthy, T.G.; McCubbin, N.A.; McFarlane, K.W.; McGarvie, S.; McGlone, H.; Mchedlidze, G.; McLaren, R.A.; McMahon, S.J.; McMahon, T.R.; McMahon, T.J.; McPherson, R.A.; Meade, A.; Mechnich, J.; Mechtel, M.; Medinnis, M.; Meera-Lebbai, R.; Meguro, T.; Mehdiyev, R.; Mehlhase, S.; Mehta, A.; Meier, K.; Meinhardt, J.; Meirose, B.; Melachrinos, C.; Mellado Garcia, B.R.; Mendoza Navas, L.; Meng, Z.; Mengarelli, A.; Menke, S.; Menot, C.; Meoni, E.; Merkl, D.; Mermod, P.; Merola, L.; Meroni, C.; Merritt, F.S.; Messina, A.M.; Messmer, I.; Metcalfe, J.; Mete, A.S.; Meuser, S.; Meyer, C.; Meyer, J-P.; Meyer, J.; Meyer, J.; Meyer, T.C.; Meyer, W.T.; Miao, J.; Michal, S.; Micu, L.; Middleton, R.P.; Miele, P.; Migas, S.; Migliaccio, A.; Mijovic, L.; Mikenberg, G.; Mikestikova, M.; Mikulec, B.; Mikuz, M.; Miller, D.W.; Miller, R.J.; Mills, W.J.; Mills, C.; Milov, A.; Milstead, D.A.; Milstein, D.; Mima, S.; Minaenko, A.A.; Minano, M.; Minashvili, I.A.; Mincer, A.I.; Mindur, B.; Mineev, M.; Ming, Y.; Mir, L.M.; Mirabelli, G.; Miralles Verge, L.; Misawa, S.; Miscetti, S.; Misiejuk, A.; Mitra, A.; Mitrevski, J.; Mitrofanov, G.Y.; Mitsou, V.A.; Mitsui, S.; Miyagawa, P.S.; Miyazaki, K.; Mjornmark, J.U.; Mladenov, D.; Moa, T.; Moch, M.; Mockett, P.; Moed, S.; Moeller, V.; Monig, K.; Moser, N.; Mohn, B.; Mohr, W.; Mohrdieck-Mock, S.; Moisseev, A.M.; Moles-Valls, R.; Molina-Perez, J.; Moneta, L.; Monk, J.; Monnier, E.; Montesano, S.; Monticelli, F.; Moore, R.W.; Moorhead, G.F.; Mora Herrera, C.; Moraes, A.; Morais, A.; Morel, J.; Morello, G.; Moreno, D.; Moreno Llacer, M.; Morettini, P.; Morgan, D.; Morii, M.; Morin, J.; Morita, Y.; Morley, A.K.; Mornacchi, G.; Morone, M-C.; Morozov, S.V.; Morris, J.D.; Moser, H.G.; Mosidze, M.; Moss, J.; Moszczynski, A.; Mount, R.; Mountricha, E.; Mouraviev, S.V.; Moye, T.H.; Moyse, E.J.W.; Mudrinic, M.; Mueller, F.; Mueller, J.; Mueller, K.; Muller, T.A.; Muenstermann, D.; Muijs, A.; Muir, A.; Munar, A.; Munwes, Y.; Murakami, K.; Murillo Garcia, R.; Murray, W.J.; Mussche, I.; Musto, E.; Myagkov, A.G.; Myska, M.; Nadal, J.; Nagai, K.; Nagano, K.; Nagasaka, Y.; Nairz, A.M.; Naito, D.; Nakamura, K.; Nakano, I.; Nanava, G.; Napier, A.; Nash, M.; Nasteva, I.; Nation, N.R.; Nattermann, T.; Naumann, T.; Nauyock, F.; Navarro, G.; Nderitu, S.K.; Neal, H.A.; Nebot, E.; Nechaeva, P.; Negri, A.; Negri, G.; Negroni, S.; Nelson, A.; Nelson, S.; Nelson, T.K.; Nemecek, S.; Nemethy, P.; Nepomuceno, A.A.; Nessi, M.; Nesterov, S.Y.; Neubauer, M.S.; Neukermans, L.; Neusiedl, A.; Neves, R.M.; Nevski, P.; Newcomer, F.M.; Nicholson, C.; Nickerson, R.B.; Nicolaidou, R.; Nicolas, L.; Nicoletti, G.; Nicquevert, B.; Niedercorn, F.; Nielsen, J.; Niinikoski, T.; Nikiforov, A.; Nikolaenko, V.; Nikolaev, K.; Nikolic-Audit, I.; Nikolopoulos, K.; Nilsen, H.; Nilsson, P.; Ninomiya, Y.; Nisati, A.; Nishiyama, T.; Nisius, R.; Nodulman, L.; Nomachi, M.; Nomidis, I.; Nomoto, H.; Nordberg, M.; Nordkvist, B.; Norniella Francisco, O.; Norton, P.R.; Notz, D.; Novakova, J.; Nozaki, M.; Nozicka, M.; Nugent, I.M.; Nuncio-Quiroz, A.E.; Nunes Hanninger, G.; Nunnemann, T.; Nurse, E.; Nyman, T.; O'Neale, S.W.; O'Neil, D.C.; O'Shea, V.; Oakham, F.G.; Oberlack, H.; Ocariz, J.; Ochi, A.; Oda, S.; Odaka, S.; Odier, J.; Odino, G.A.; Ogren, H.; Oh, A.; Oh, S.H.; Ohm, C.C.; Ohshima, T.; Ohshita, H.; Ohska, T.K.; Ohsugi, T.; Okada, S.; Okawa, H.; Okumura, Y.; Okuyama, T.; Olcese, M.; Olchevski, A.G.; Oliveira, M.; Oliveira Damazio, D.; Oliver, C.; Oliver, J.; Oliver Garcia, E.; Olivito, D.; Olszewski, A.; Olszowska, J.; Omachi, C.; Onofre, A.; Onyisi, P.U.E.; Oram, C.J.; Ordonez, G.; Oreglia, M.J.; Orellana, F.; Oren, Y.; Orestano, D.; Orlov, I.; Oropeza Barrera, C.; Orr, R.S.; Ortega, E.O.; Osculati, B.; Ospanov, R.; Osuna, C.; Otero y Garzon, G.; Ottersbach, J.P; Ottewell, B.; Ouchrif, M.; Ould-Saada, F.; Ouraou, A.; Ouyang, Q.; Owen, M.; Owen, S.; Oyarzun, A; Oye, O.K.; Ozcan, V.E.; Ozone, K.; Ozturk, N.; Pacheco Pages, A.; Padilla Aranda, C.; Paganis, E.; Paige, F.; Pajchel, K.; Palestini, S.; Palla, J.; Pallin, D.; Palma, A.; Palmer, J.D.; Palmer, M.J.; Pan, Y.B.; Panagiotopoulou, E.; Panes, B.; Panikashvili, N.; Panin, V.N.; Panitkin, S.; Pantea, D.; Panuskova, M.; Paolone, V.; Paoloni, A.; Papadopoulou, Th.D.; Paramonov, A.; Park, S.J.; Park, W.; Parker, M.A.; Parker, S.I.; Parodi, F.; Parsons, J.A.; Parzefall, U.; Pasqualucci, E.; Passeri, A.; Pastore, F.; Pastore, Fr.; Pasztor, G.; Pataraia, S.; Patel, N.; Pater, J.R.; Patricelli, S.; Pauly, T.; Peak, L.S.; Pecsy, M.; Pedraza Morales, M.I.; Peeters, S.J.M.; Peleganchuk, S.V.; Peng, H.; Pengo, R.; Penson, A.; Penwell, J.; Perantoni, M.; Perez, K.; Perez Codina, E.; Perez Garcia-Estan, M.T.; Perez Reale, V.; Peric, I.; Perini, L.; Pernegger, H.; Perrino, R.; Perrodo, P.; Persembe, S.; Perus, P.; Peshekhonov, V.D.; Petereit, E.; Peters, O.; Petersen, B.A.; Petersen, J.; Petersen, T.C.; Petit, E.; Petridou, C.; Petrolo, E.; Petrucci, F.; Petschull, D; Petteni, M.; Pezoa, R.; Pfeifer, B.; Phan, A.; Phillips, A.W.; Piacquadio, G.; Piccaro, E.; Piccinini, M.; Pickford, A.; Piegaia, R.; Pilcher, J.E.; Pilkington, A.D.; Pina, J.; Pinamonti, M.; Pinfold, J.L.; Ping, J.; Pinto, B.; Pirotte, O.; Pizio, C.; Placakyte, R.; Plamondon, M.; Plano, W.G.; Pleier, M.A.; Pleskach, A.V.; Poblaguev, A.; Poddar, S.; Podlyski, F.; Poffenberger, P.; Poggioli, L.; Poghosyan, T.; Pohl, M.; Polci, F.; Polesello, G.; Policicchio, A.; Polini, A.; Poll, J.; Polychronakos, V.; Pomarede, D.M.; Pomeroy, D.; Pommes, K.; Ponsot, P.; Pontecorvo, L.; Pope, B.G.; Popeneciu, G.A.; Popescu, R.; Popovic, D.S.; Poppleton, A.; Popule, J.; Portell Bueso, X.; Porter, R.; Posch, C.; Pospelov, G.E.; Pospisil, S.; Potekhin, M.; Potrap, I.N.; Potter, C.J.; Potter, C.T.; Potter, K.P.; Poulard, G.; Poveda, J.; Prabhu, R.; Pralavorio, P.; Prasad, S.; Prata, M.; Pravahan, R.; Pretzl, K.; Pribyl, L.; Price, D.; Price, L.E.; Price, M.J.; Prichard, P.M.; Prieur, D.; Primavera, M.; Prokofiev, K.; Prokoshin, F.; Protopopescu, S.; Proudfoot, J.; Prudent, X.; Przysiezniak, H.; Psoroulas, S.; Ptacek, E.; Puigdengoles, C.; Purdham, J.; Purohit, M.; Puzo, P.; Pylypchenko, Y.; Qi, M.; Qian, J.; Qian, W.; Qian, Z.; Qin, Z.; Qing, D.; Quadt, A.; Quarrie, D.R.; Quayle, W.B.; Quinonez, F.; Raas, M.; Radeka, V.; Radescu, V.; Radics, B.; Rador, T.; Ragusa, F.; Rahal, G.; Rahimi, A.M.; Rahm, D.; Raine, C.; Raith, B.; Rajagopalan, S.; Rajek, S.; Rammensee, M.; Rammes, M.; Ramstedt, M.; Ratoff, P.N.; Rauscher, F.; Rauter, E.; Raymond, M.; Read, A.L.; Rebuzzi, D.M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reeves, K.; Reichold, A.; Reinherz-Aronis, E.; Reinsch, A; Reisinger, I.; Reljic, D.; Rembser, C.; Ren, Z.L.; Renkel, P.; Rensch, B.; Rescia, S.; Rescigno, M.; Resconi, S.; Resende, B.; Reznicek, P.; Rezvani, R.; Richards, A.; Richards, R.A.; Richter, R.; Richter-Was, E.; Ridel, M.; Rieke, S.; Rijpstra, M.; Rijssenbeek, M.; Rimoldi, A.; Rinaldi, L.; Rios, R.R.; Riu, I.; Rivoltella, G.; Rizatdinova, F.; Rizvi, E.; Roa Romero, D.A.; Robertson, S.H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, JEM; Robinson, M.; Robson, A.; Rocha de Lima, J.G.; Roda, C.; Roda Dos Santos, D.; Rodier, S.; Rodriguez, D.; Rodriguez Garcia, Y.; Roe, S.; Rohne, O.; Rojo, V.; Rolli, S.; Romaniouk, A.; Romanov, V.M.; Romeo, G.; Romero Maltrana, D.; Roos, L.; Ros, E.; Rosati, S.; Rosenbaum, G.A.; Rosenberg, E.I.; Rosendahl, P.L.; Rosselet, L.; Rossetti, V.; Rossi, L.P.; Rossi, L.; Rotaru, M.; Rothberg, J.; Rottlander, I.; Rousseau, D.; Royon, C.R.; Rozanov, A.; Rozen, Y.; Ruan, X.; Ruckert, B.; Ruckstuhl, N.; Rud, V.I.; Rudolph, G.; Ruhr, F.; Ruggieri, F.; Ruiz-Martinez, A.; Rulikowska-Zarebska, E.; Rumiantsev, V.; Rumyantsev, L.; Runge, K.; Runolfsson, O.; Rurikova, Z.; Rusakovich, N.A.; Rust, D.R.; Rutherfoord, J.P.; Ruwiedel, C.; Ruzicka, P.; Ryabov, Y.F.; Ryadovikov, V.; Ryan, P.; Rybkin, G.; Rzaeva, S.; Saavedra, A.F.; Sadrozinski, H.F-W.; Sadykov, R.; Safai Tehrani, F.; Sakamoto, H.; Sala, P.; Salamanna, G.; Salamon, A.; Saleem, M.; Salihagic, D.; Salnikov, A.; Salt, J.; Salto Bauza, O.; Salvachua Ferrando, B.M.; Salvatore, D.; Salvatore, F.; Salvucci, A.; Salzburger, A.; Sampsonidis, D.; Samset, B.H.; Sandaker, H.; Sander, H.G.; Sanders, M.P.; Sandhoff, M.; Sandhu, P.; Sandoval, T.; Sandstroem, R.; Sandvoss, S.; Sankey, D.P.C.; Sanny, B.; Sansoni, A.; Santamarina Rios, C.; Santoni, C.; Santonico, R.; Santos, H.; Saraiva, J.G.; Sarangi, T.; Sarkisyan-Grinbaum, E.; Sarri, F.; Sartisohn, G.; Sasaki, O.; Sasaki, T.; Sasao, N.; Satsounkevitch, I.; Sauvage, G.; Savard, P.; Savine, A.Y.; Savinov, V.; Savva, P.; Sawyer, L.; Saxon, D.H.; Says, L.P.; Sbarra, C.; Sbrizzi, A.; Scallon, O.; Scannicchio, D.A.; Schaarschmidt, J.; Schacht, P.; Schafer, U.; Schaetzel, S.; Schaffer, A.C.; Schaile, D.; Schaller, M.; Schamberger, R.D.; Schamov, A.G.; Scharf, V.; Schegelsky, V.A.; Scheirich, D.; Schernau, M.; Scherzer, M.I.; Schiavi, C.; Schieck, J.; Schioppa, M.; Schlenker, S.; Schlereth, J.L.; Schmidt, E.; Schmidt, M.P.; Schmieden, K.; Schmitt, C.; Schmitz, M.; Scholte, R.C.; Schoning, A.; Schott, M.; Schouten, D.; Schovancova, J.; Schram, M.; Schreiner, A.; Schroeder, C.; Schroer, N.; Schroers, M.; Schroff, D.; Schuh, S.; Schuler, G.; Schultes, J.; Schultz-Coulon, H.C.; Schumacher, J.W.; Schumacher, M.; Schumm, B.A.; Schune, Ph.; Schwanenberger, C.; Schwartzman, A.; Schweiger, D.; Schwemling, Ph.; Schwienhorst, R.; Schwierz, R.; Schwindling, J.; Scott, W.G.; Searcy, J.; Sedykh, E.; Segura, E.; Seidel, S.C.; Seiden, A.; Seifert, F.; Seixas, J.M.; Sekhniaidze, G.; Seliverstov, D.M.; Sellden, B.; Sellers, G.; Seman, M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Seuster, R.; Severini, H.; Sevior, M.E.; Sfyrla, A.; Shabalina, E.; Shamim, M.; Shan, L.Y.; Shank, J.T.; Shao, Q.T.; Shapiro, M.; Shatalov, P.B.; Shaver, L.; Shaw, C.; Shaw, K.; Sherman, D.; Sherwood, P.; Shibata, A.; Shield, P.; Shimizu, S.; Shimojima, M.; Shin, T.; Shmeleva, A.; Shochet, M.J.; Shupe, M.A.; Sicho, P.; Sidoti, A.; Siebel, A.; Siebel, M.; Siegert, F; Siegrist, J.; Sijacki, Dj.; Silbert, O.; Silva, J.; Silver, Y.; Silverstein, D.; Silverstein, S.B.; Simak, V.; Simic, Lj.; Simion, S.; Simmons, B.; Simonyan, M.; Sinervo, P.; Sinev, N.B.; Sipica, V.; Siragusa, G.; Sisakyan, A.N.; Sivoklokov, S.Yu.; Sjolin, J.; Sjursen, T.B.; Skinnari, L.A.; Skovpen, K.; Skubic, P.; Skvorodnev, N.; Slater, M.; Slavicek, T.; Sliwa, K.; Sloan, T.J.; Sloper, J.; Smakhtin, V.; Smirnov, S.Yu.; Smirnov, Y.; Smirnova, L.N.; Smirnova, O.; Smith, B.C.; Smith, D.; Smith, K.M.; Smizanska, M.; Smolek, K.; Snesarev, A.A.; Snow, S.W.; Snow, J.; Snuverink, J.; Snyder, S.; Soares, M.; Sobie, R.; Sodomka, J.; Soffer, A.; Solans, C.A.; Solar, M.; Solc, J.; Solfaroli Camillocci, E.; Solodkov, A.A.; Solovyanov, O.V.; Soluk, R.; Sondericker, J.; Soni, N.; Sopko, V.; Sopko, B.; Sorbi, M.; Sosebee, M.; Soukharev, A.; Spagnolo, S.; Spano, F.; Speckmayer, P.; Spencer, E.; Spighi, R.; Spigo, G.; Spila, F.; Spiriti, E.; Spiwoks, R.; Spogli, L.; Spousta, M.; Spreitzer, T.; Spurlock, B.; St. Denis, R.D.; Stahl, T.; Stahlman, J.; Stamen, R.; Stancu, S.N.; Stanecka, E.; Stanek, R.W.; Stanescu, C.; Stapnes, S.; Starchenko, E.A.; Stark, J.; Staroba, P.; Starovoitov, P.; Stastny, J.; Staude, A.; Stavina, P.; Stavropoulos, G.; Steele, G.; Stefanidis, E.; Steinbach, P.; Steinberg, P.; Stekl, I.; Stelzer, B.; Stelzer, H.J.; Stelzer-Chilton, O.; Stenzel, H.; Stevenson, K.; Stewart, G.A.; Stiller, W.; Stockmanns, T.; Stockton, M.C.; Stodulski, M.; Stoerig, K.; Stoicea, G.; Stonjek, S.; Strachota, P.; Stradling, A.R.; Straessner, A.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strang, M.; Strauss, M.; Strizenec, P.; Strohmer, R.; Strom, D.M.; Strong, J.A.; Stroynowski, R.; Strube, J.; Stugu, B.; Stumer, I.; Sturm, P.; Soh, D.A.; Su, D.; Subramania, S.; Sugaya, Y.; Sugimoto, T.; Suhr, C.; Suita, K.; Suk, M.; Sulin, V.V.; Sultansoy, S.; Sumida, T.; Sun, X.H.; Sundermann, J.E.; Suruliz, K.; Sushkov, S.; Susinno, G.; Sutton, M.R.; Suzuki, Y.; Sviridov, Yu.M.; Swedish, S.; Sykora, I.; Sykora, T.; Szczygiel, R.R.; Szeless, B.; Szymocha, T.; Sanchez, J.; Ta, D.; Taboada Gameiro, S.; Tackmann, K.; Taffard, A.; Tafirout, R.; Taga, A.; Takahashi, Y.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Talby, M.; Talyshev, A.; Tamsett, M.C.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tanaka, S.; Tanaka, Y.; Tani, K.; Tappern, G.P.; Tapprogge, S.; Tardif, D.; Tarem, S.; Tarrade, F.; Tartarelli, G.F.; Tas, P.; Tasevsky, M.; Tassi, E.; Tatarkhanov, M.; Taylor, C.; Taylor, F.E.; Taylor, G.; Taylor, G.N.; Taylor, R.P.; Taylor, W.; Teixeira Dias Castanheira, M.; Teixeira-Dias, P.; Temming, K.K.; Ten Kate, H.; Teng, P.K.; Tennenbaum-Katan, Y.D.; Terada, S.; Terashi, K.; Terron, J.; Terwort, M.; Testa, M.; Teuscher, R.J.; Tevlin, C.M.; Thadome, J.; Therhaag, J.; Theveneaux-Pelzer, T.; Thioye, M.; Thoma, S.; Thomas, J.P.; Thompson, E.N.; Thompson, P.D.; Thompson, P.D.; Thompson, R.J.; Thompson, A.S.; Thomson, E.; Thun, R.P.; Tic, T.; Tikhomirov, V.O.; Tikhonov, Y.A.; Timmermans, C.J.W.P.; Tipton, P.; Tique Aires Viegas, F.J.; Tisserant, S.; Tobias, J.; Toczek, B.; Todorov, T.; Todorova-Nova, S.; Toggerson, B.; Tojo, J.; Tokar, S.; Tokunaga, K.; Tokushuku, K.; Tollefson, K.; Tomasek, L.; Tomasek, M.; Tomoto, M.; Tompkins, D.; Tompkins, L.; Toms, K.; Tonazzo, A.; Tong, G.; Tonoyan, A.; Topfel, C.; Topilin, N.D.; Torchiani, I.; Torrence, E.; Torro Pastor, E.; Toth, J.; Touchard, F.; Tovey, D.R.; Traynor, D.; Trefzger, T.; Treis, J.; Tremblet, L.; Tricoli, A.; Trigger, I.M.; Trincaz-Duvoid, S.; Trinh, T.N.; Tripiana, M.F.; Triplett, N.; Trischuk, W.; Trivedi, A.; Trocme, B.; Troncon, C.; Trottier-McDonald, M.; Trzupek, A.; Tsarouchas, C.; Tseng, J.C-L.; Tsiakiris, M.; Tsiareshka, P.V.; Tsionou, D.; Tsipolitis, G.; Tsiskaridze, V.; Tskhadadze, E.G.; Tsukerman, I.I.; Tsulaia, V.; Tsung, J.W.; Tsuno, S.; Tsybychev, D.; Tuggle, J.M.; Turala, M.; Turecek, D.; Turk Cakir, I.; Turlay, E.; Tuts, P.M.; Twomey, M.S.; Tylmad, M.; Tyndel, M.; Typaldos, D.; Tyrvainen, H.; Tzamarioudaki, E.; Tzanakos, G.; Uchida, K.; Ueda, I.; Ueno, R.; Ugland, M.; Uhlenbrock, M.; Uhrmacher, M.; Ukegawa, F.; Unal, G.; Underwood, D.G.; Undrus, A.; Unel, G.; Unno, Y.; Urbaniec, D.; Urkovsky, E.; Urquijo, P.; Urrejola, P.; Usai, G.; Uslenghi, M.; Vacavant, L.; Vacek, V.; Vachon, B.; Vahsen, S.; Valderanis, C.; Valenta, J.; Valente, P.; Valentinetti, S.; Valkar, S.; Valladolid Gallego, E.; Vallecorsa, S.; Valls Ferrer, J.A.; Van Berg, R.; van der Graaf, H.; van der Kraaij, E.; van der Poel, E.; van der Ster, D.; Van Eijk, B.; van Eldik, N.; van Gemmeren, P.; van Kesteren, Z.; van Vulpen, I.; Vandelli, W.; Vandoni, G.; Vaniachine, A.; Vankov, P.; Vannucci, F.; Varela Rodriguez, F.; Vari, R.; Varnes, E.W.; Varouchas, D.; Vartapetian, A.; Varvell, K.E.; Vasilyeva, L.; Vassilakopoulos, V.I.; Vazeille, F.; Vegni, G.; Veillet, J.J.; Vellidis, C.; Veloso, F.; Veness, R.; Veneziano, S.; Ventura, A.; Ventura, D.; Ventura, S.; Venturi, M.; Venturi, N.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J.C.; Vertogardov, L.; Vetterli, M.C.; Vichou, I.; Vickey, T.; Viehhauser, G.H.A.; Viel, S.; Villa, M.; Villani, E.G.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M.G.; Vinek, E.; Vinogradov, V.B.; Virchaux, M.; Viret, S.; Virzi, J.; Vitale, A.; Vitells, O.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vlasak, M.; Vlasov, N.; Vogel, A.; Vogt, H.; Vokac, P.; Volpi, M.; Volpini, G.; von der Schmitt, H.; von Loeben, J.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorobiev, A.P.; Vorwerk, V.; Vos, M.; Voss, R.; Voss, T.T.; Vossebeld, J.H.; Vovenko, A.S.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vu Anh, T.; Vudragovic, D.; Vuillermet, R.; Vukotic, I.; Wagner, W.; Wagner, P.; Wahlen, H.; Walbersloh, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wall, R.; Waller, P.; Wang, C.; Wang, H.; Wang, J.; Wang, J.C.; Wang, S.M.; Warburton, A.; Ward, C.P.; Warsinsky, M.; Wastie, R.; Watkins, P.M.; Watson, A.T.; Watson, M.F.; Watts, G.; Watts, S.; Waugh, A.T.; Waugh, B.M.; Webel, M.; Weber, J.; Weber, M.; Weber, M.S.; Weber, P.; Weidberg, A.R.; Weingarten, J.; Weiser, C.; Wellenstein, H.; Wellisch, H.P.; Wells, P.S.; Wen, M.; Wenaus, T.; Wendler, S.; Weng, Z.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Werth, M.; Werthenbach, U.; Wessels, M.; Whalen, K.; Wheeler-Ellis, S.J.; Whitaker, S.P.; White, A.; White, M.J.; White, S.; Whitehead, S.R.; Whiteson, D.; Whittington, D.; Wicek, F.; Wicke, D.; Wickens, F.J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik, L.A.M.; Wildauer, A.; Wildt, M.A.; Wilhelm, I.; Wilkens, H.G.; Will, J.Z.; Williams, E.; Williams, H.H.; Willis, W.; Willocq, S.; Wilson, J.A.; Wilson, M.G.; Wilson, A.; Wingerter-Seez, I.; Winkelmann, S.; Winklmeier, F.; Wittgen, M.; Woehrling, E.; Wolter, M.W.; Wolters, H.; Wosiek, B.K.; Wotschack, J.; Woudstra, M.J.; Wraight, K.; Wright, C.; Wright, D.; Wrona, B.; Wu, S.L.; Wu, X.; Wuestenfeld, J.; Wulf, E.; Wunstorf, R.; Wynne, B.M.; Xaplanteris, L.; Xella, S.; Xie, S.; Xie, Y.; Xu, C.; Xu, D.; Xu, G.; Xu, N.; Yabsley, B.; Yamada, M.; Yamamoto, A.; Yamamoto, K.; Yamamoto, S.; Yamamura, T.; Yamaoka, J.; Yamazaki, T.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, S.; Yang, U.K.; Yang, Y.; Yang, Y.; Yang, Z.; Yao, W-M.; Yao, Y.; Yasu, Y.; Ye, J.; Ye, S.; Yilmaz, M.; Yoosoofmiya, R.; Yorita, K.; Yoshida, R.; Young, C.; Youssef, S.P.; Yu, D.; Yu, J.; Yu, J.; Yuan, J.; Yuan, L.; Yurkewicz, A.; Zaets, V.G.; Zaidan, R.; Zaitsev, A.M.; Zajacova, Z.; Zalite, Yo.K.; Zambrano, V.; Zanello, L.; Zarzhitsky, P.; Zaytsev, A.; Zdrazil, M.; Zeitnitz, C.; Zeller, M.; Zema, P.F.; Zemla, A.; Zendler, C.; Zenin, A.V.; Zenin, O.; Zenis, T.; Zenonos, Z.; Zenz, S.; Zerwas, D.; Zevi della Porta, G.; Zhan, Z.; Zhang, H.; Zhang, J.; Zhang, Q.; Zhang, X.; Zhao, L.; Zhao, T.; Zhao, Z.; Zhemchugov, A.; Zheng, S.; Zhong, J.; Zhou, B.; Zhou, N.; Zhou, Y.; Zhu, C.G.; Zhu, H.; Zhu, Y.; Zhuang, X.; Zhuravlov, V.; Zilka, B.; Zimmermann, R.; Zimmermann, S.; Zimmermann, S.; Ziolkowski, M.; Zitoun, R.; Zivkovic, L.; Zmouchko, V.V.; Zobernig, G.; Zoccoli, A.; Zolnierowski, Y.; Zsenei, A.; zur Nedden, M.; Zutshi, V.

2010-01-01

A search for new heavy particles manifested as narrow resonances in two-jet final states is presented. The data were produced in 7 TeV proton-proton collisions by the Large Hadron Collider (LHC) and correspond to an integrated luminosity of 315 nb^-1 collected by the ATLAS detector. No resonances were observed. Upper limits were set on the product of cross section and detector acceptance for excited-quark (q*) production as a function of q* mass. These exclude at the 95% CL the q* mass interval 0.40 < mq* < 1.26 TeV, extending the reach of previous experiments.

Search for new particles in two-jet final states in 7 TeV proton-proton collisions with the ATLAS detector at the LHC.

Science.gov (United States)

Aad, G; Abbott, B; Abdallah, J; Abdelalim, A A; Abdesselam, A; Abdinov, O; Abi, B; Abolins, M; Abramowicz, H; Abreu, H; Acerbi, E; Acharya, B S; Ackers, M; Adams, D L; Addy, T N; Adelman, J; Aderholz, M; Adomeit, S; Adorisio, C; Adragna, P; Adye, T; Aefsky, S; Aguilar-Saavedra, J A; Aharrouche, M; Ahlen, S P; Ahles, F; Ahmad, A; Ahmed, H; Ahsan, M; Aielli, G; Akdogan, T; Akesson, T P A; Akimoto, G; Akimov, A V; Aktas, A; Alam, M S; Alam, M A; Albrand, S; Aleksa, M; Aleksandrov, I N; Aleppo, M; Alessandria, F; Alexa, C; Alexander, G; Alexandre, G; Alexopoulos, T; Alhroob, M; Aliev, M; Alimonti, G; Alison, J; Aliyev, M; Allport, P P; Allwood-Spiers, S E; Almond, J; Aloisio, A; Alon, R; Alonso, A; Alonso, J; Alviggi, M G; Amako, K; Amaral, P; Ambrosio, G; Amelung, C; Ammosov, V V; Amorim, A; Amorós, G; Amram, N; Anastopoulos, C; Andeen, T; Anders, C F; Anderson, K J; Andreazza, A; Andrei, V; Andrieux, M-L; Anduaga, X S; Angerami, A; Anghinolfi, F; Anjos, N; Annovi, A; Antonaki, A; Antonelli, M; Antonelli, S; Antos, J; Antunovic, B; Anulli, F; Aoun, S; Arabidze, G; Aracena, I; Arai, Y; Arce, A T H; Archambault, J P; Arfaoui, S; Arguin, J-F; Argyropoulos, T; Arik, E; Arik, M; Armbruster, A J; Arms, K E; Armstrong, S R; Arnaez, O; Arnault, C; Artamonov, A; Arutinov, D; Asai, M; Asai, S; Asfandiyarov, R; Ask, S; Asman, B; Asner, D; Asquith, L; Assamagan, K; Astbury, A; Astvatsatourov, A; Atoian, G; Aubert, B; Auerbach, B; Auge, E; Augsten, K; Aurousseau, M; Austin, N; Avolio, G; Avramidou, R; Axen, D; Ay, C; Azuelos, G; Azuma, Y; Baak, M A; Baccaglioni, G; Bacci, C; Bach, A M; Bachacou, H; Bachas, K; Bachy, G; Backes, M; Badescu, E; Bagnaia, P; Bai, Y; Bailey, D C; Bain, T; Baines, J T; Baker, O K; Baker, M D; Baker, S; Baltasar Dos Santos Pedrosa, F; Banas, E; Banerjee, P; Banerjee, S; Banfi, D; Bangert, A; Bansal, V; Baranov, S P; Baranov, S; Barashkou, A; Barbaro Galtieri, A; Barber, T; Barberio, E L; Barberis, D; Barbero, M; Bardin, D Y; Barillari, T; Barisonzi, M; Barklow, T; Barlow, N; Barnett, B M; Barnett, R M; Baroncelli, A; Barone, M; Barr, A J; Barreiro, F; Barreiro Guimarães da Costa, J; Barrillon, P; Bartoldus, R; Bartsch, D; Bates, R L; Batkova, L; Batley, J R; Battaglia, A; Battistin, M; Battistoni, G; Bauer, F; Bawa, H S; Bazalova, M; Beare, B; Beau, T; Beauchemin, P H; Beccherle, R; Bechtle, P; Beck, G A; Beck, H P; Beckingham, M; Becks, K H; Beddall, A J; Beddall, A; Bednyakov, V A; Bee, C; Begel, M; Behar Harpaz, S; Behera, P K; Beimforde, M; Belanger-Champagne, C; Belhorma, B; Bell, P J; Bell, W H; Bella, G; Bellagamba, L; Bellina, F; Bellomo, G; Bellomo, M; Belloni, A; Belotskiy, K; Beltramello, O; Ben Ami, S; Benary, O; Benchekroun, D; Benchouk, C; Bendel, M; Benedict, B H; Benekos, N; Benhammou, Y; Benincasa, G P; Benjamin, D P; Benoit, M; Bensinger, J R; Benslama, K; Bentvelsen, S; Beretta, M; Berge, D; Bergeaas Kuutmann, E; Berger, N; Berghaus, F; Berglund, E; Beringer, J; Bernardet, K; Bernat, P; Bernhard, R; Bernius, C; Berry, T; Bertin, A; Bertinelli, F; Bertolucci, F; Bertolucci, S; Besana, M I; Besson, N; Bethke, S; Bhimji, W; Bianchi, R M; Bianco, M; Biebel, O; Biesiada, J; Biglietti, M; Bilokon, H; Binder, M; Bindi, M; Binet, S; Bingul, A; Bini, C; Biscarat, C; Bischof, R; Bitenc, U; Black, K M; Blair, R E; Blanchard, J-B; Blanchot, G; Blocker, C; Blocki, J; Blondel, A; Blum, W; Blumenschein, U; Boaretto, C; Bobbink, G J; Bocci, A; Bocian, D; Bock, R; Boddy, C R; Boehler, M; Boek, J; Boelaert, N; Böser, S; Bogaerts, J A; Bogouch, A; Bohm, C; Bohm, J; Boisvert, V; Bold, T; Boldea, V; Bondarenko, V G; Bondioli, M; Boonekamp, M; Boorman, G; Booth, C N; Booth, P; Booth, J R A; Bordoni, S; Borer, C; Borisov, A; Borissov, G; Borjanovic, I; Borroni, S; Bos, K; Boscherini, D; Bosman, M; Boterenbrood, H; Botterill, D; Bouchami, J; Boudreau, J; Bouhova-Thacker, E V; Boulahouache, C; Bourdarios, C; Boveia, A; Boyd, J; Boyko, I R; Bozhko, N I; Bozovic-Jelisavcic, I; Braccini, S; Bracinik, J; Braem, A; Brambilla, E; Branchini, P; Brandenburg, G W; Brandt, A; Brandt, G; Brandt, O; Bratzler, U; Brau, B; Brau, J E; Braun, H M; Brelier, B; Bremer, J; Brenner, R; Bressler, S; Breton, D; Brett, N D; Bright-Thomas, P G; Britton, D; Brochu, F M; Brock, I; Brock, R; Brodbeck, T J; Brodet, E; Broggi, F; Bromberg, C; Brooijmans, G; Brooks, W K; Brown, G; Brubaker, E; Bruckman de Renstrom, P A; Bruncko, D; Bruneliere, R; Brunet, S; Bruni, A; Bruni, G; Bruschi, M; Buanes, T; Bucci, F; Buchanan, J; Buchanan, N J; Buchholz, P; Buckingham, R M; Buckley, A G; Budagov, I A; Budick, B; Büscher, V; Bugge, L; Buira-Clark, D; Buis, E J; Bulekov, O; Bunse, M; Buran, T; Burckhart, H; Burdin, S; Burgess, T; Burke, S; Busato, E; Bussey, P; Buszello, C P; Butin, F; Butler, B; Butler, J M; Buttar, C M; Butterworth, J M; Byatt, T; Caballero, J; Cabrera Urbán, S; Caccia, M; Caforio, D; Cakir, O; Calafiura, P; Calderini, G; Calfayan, P; Calkins, R; Caloba, L P; Caloi, R; Calvet, D; Camard, A; Camarri, P; Cambiaghi, M; Cameron, D; Cammin, J; Campana, S; Campanelli, M; Canale, V; Canelli, F; Canepa, A; Cantero, J; Capasso, L; Capeans Garrido, M D M; Caprini, I; Caprini, M; Caprio, M; Capriotti, D; Capua, M; Caputo, R; Caramarcu, C; Cardarelli, R; Carli, T; Carlino, G; Carminati, L; Caron, B; Caron, S; Carpentieri, C; Carrillo Montoya, G D; Carron Montero, S; Carter, A A; Carter, J R; Carvalho, J; Casadei, D; Casado, M P; Cascella, M; Caso, C; Castaneda Hernandez, A M; Castaneda-Miranda, E; Castillo Gimenez, V; Castro, N F; Cataldi, G; Cataneo, F; Catinaccio, A; Catmore, J R; Cattai, A; Cattani, G; Caughron, S; Cauz, D; Cavallari, A; Cavalleri, P; Cavalli, D; Cavalli-Sforza, M; Cavasinni, V; Cazzato, A; Ceradini, F; Cerna, C; Cerqueira, A S; Cerri, A; Cerrito, L; Cerutti, F; Cervetto, M; Cetin, S A; Cevenini, F; Chafaq, A; Chakraborty, D; Chan, K; Chapman, J D; Chapman, J W; Chareyre, E; Charlton, D G; Chavda, V; Cheatham, S; Chekanov, S; Chekulaev, S V; Chelkov, G A; Chen, H; Chen, L; Chen, S; Chen, T; Chen, X; Cheng, S; Cheplakov, A; Chepurnov, V F; Cherkaoui El Moursli, R; Tcherniatine, V; Chesneanu, D; Cheu, E; Cheung, S L; Chevalier, L; Chevallier, F; Chiarella, V; Chiefari, G; Chikovani, L; Childers, J T; Chilingarov, A; Chiodini, G; Chizhov, M V; Choudalakis, G; Chouridou, S; Christidi, I A; Christov, A; Chromek-Burckhart, D; Chu, M L; Chudoba, J; Ciapetti, G; Ciftci, A K; Ciftci, R; Cinca, D; Cindro, V; Ciobotaru, M D; Ciocca, C; Ciocio, A; Cirilli, M; Citterio, M; Clark, A; Clark, P J; Cleland, W; Clemens, J C; Clement, B; Clement, C; Clifft, R W; Coadou, Y; Cobal, M; Coccaro, A; Cochran, J; Coe, P; Coelli, S; Coggeshall, J; Cogneras, E; Cojocaru, C D; Colas, J; Cole, B; Colijn, A P; Collard, C; Collins, N J; Collins-Tooth, C; Collot, J; Colon, G; Coluccia, R; Comune, G; Conde Muiño, P; Coniavitis, E; Conidi, M C; Consonni, M; Constantinescu, S; Conta, C; Conventi, F; Cook, J; Cooke, M; Cooper, B D; Cooper-Sarkar, A M; Cooper-Smith, N J; Copic, K; Cornelissen, T; Corradi, M; Correard, S; Corriveau, F; Corso-Radu, A; Cortes-Gonzalez, A; Cortiana, G; Costa, G; Costa, M J; Costanzo, D; Costin, T; Côté, D; Coura Torres, R; Courneyea, L; Cowan, G; Cowden, C; Cox, B E; Cranmer, K; Cranshaw, J; Cristinziani, M; Crosetti, G; Crupi, R; Crépé-Renaudin, S; Cuenca Almenar, C; Cuhadar Donszelmann, T; Cuneo, S; Curatolo, M; Curtis, C J; Cwetanski, P; Czirr, H; Czyczula, Z; D'Auria, S; D'Onofrio, M; D'Orazio, A; Da Rocha Gesualdi Mello, A; Da Silva, P V M; Da Via, C; Dabrowski, W; Dahlhoff, A; Dai, T; Dallapiccola, C; Dallison, S J; Dalmau, J; Daly, C H; Dam, M; Dameri, M; Danielsson, H O; Dankers, R; Dannheim, D; Dao, V; Darbo, G; Darlea, G L; Daum, C; Dauvergne, J P; Davey, W; Davidek, T; Davidson, N; Davidson, R; Davies, M; Davison, A R; Dawe, E; Dawson, I; Dawson, J W; Daya, R K; De, K; de Asmundis, R; De Castro, S; De Castro Faria Salgado, P E; De Cecco, S; de Graat, J; De Groot, N; de Jong, P; De La Cruz-Burelo, E; De La Taille, C; De Lotto, B; De Mora, L; De Nooij, L; De Oliveira Branco, M; De Pedis, D; de Saintignon, P; De Salvo, A; De Sanctis, U; De Santo, A; De Vivie De Regie, J B; De Zorzi, G; Dean, S; Dedes, G; Dedovich, D V; Defay, P O; Degenhardt, J; Dehchar, M; Deile, M; Del Papa, C; Del Peso, J; Del Prete, T; Dell'acqua, A; Dell'asta, L; Della Pietra, M; Della Volpe, D; Delmastro, M; Delpierre, P; Delruelle, N; Delsart, P A; Deluca, C; Demers, S; Demichev, M; Demirkoz, B; Deng, J; Deng, W; Denisov, S P; Dennis, C; Derkaoui, J E; Derue, F; Dervan, P; Desch, K; Deviveiros, P O; Dewhurst, A; Dewilde, B; Dhaliwal, S; Dhullipudi, R; Di Ciaccio, A; Di Ciaccio, L; Di Domenico, A; Di Girolamo, A; Di Girolamo, B; Di Luise, S; Di Mattia, A; Di Nardo, R; Di Simone, A; Di Sipio, R; Diaz, M A; Diaz Gomez, M M; Diblen, F; Diehl, E B; Dietl, H; Dietrich, J; Dietzsch, T A; Diglio, S; Dindar Yagci, K; Dingfelder, J; Dionisi, C; Dita, P; Dita, S; Dittus, F; Djama, F; Djilkibaev, R; Djobava, T; do Vale, M A B; Do Valle Wemans, A; Doan, T K O; Dobbs, M; Dobinson, R; Dobos, D; Dobson, E; Dobson, M; Dodd, J; Dogan, O B; Doglioni, C; Doherty, T; Doi, Y; Dolejsi, J; Dolenc, I; Dolezal, Z; Dolgoshein, B A; Dohmae, T; Donega, M; Donini, J; Dopke, J; Doria, A; Dos Anjos, A; Dosil, M; Dotti, A; Dova, M T; Dowell, J D; Doxiadis, A; Doyle, A T; Drasal, Z; Drees, J; Dressnandt, N; Drevermann, H; Driouichi, C; Dris, M; Drohan, J G; Dubbert, J; Dubbs, T; Dube, S; Duchovni, E; Duckeck, G; Dudarev, A; Dudziak, F; Dührssen, M; Duerdoth, I P; Duflot, L; Dufour, M-A; Dunford, M; Duran Yildiz, H; Dushkin, A; Duxfield, R; Dwuznik, M; Dydak, F; Dzahini, D; Düren, M; Ebenstein, W L; Ebke, J; Eckert, S; Eckweiler, S; Edmonds, K; Edwards, C A; Efthymiopoulos, I; Egorov, K; Ehrenfeld, W; Ehrich, T; Eifert, T; Eigen, G; Einsweiler, K; Eisenhandler, E; Ekelof, T; El Kacimi, M; Ellert, M; Elles, S; Ellinghaus, F; Ellis, K; Ellis, N; Elmsheuser, J; Elsing, M; Ely, R; Emeliyanov, D; Engelmann, R; Engl, A; Epp, B; Eppig, A; Erdmann, J; Ereditato, A; Eremin, V; Eriksson, D; Ermoline, I; Ernst, J; Ernst, M; Ernwein, J; Errede, D; Errede, S; Ertel, E; Escalier, M; Escobar, C; Espinal Curull, X; Esposito, B; Etienne, F; Etienvre, A I; Etzion, E; Evans, H; Evdokimov, V N; Fabbri, L; Fabre, C; Facius, K; Fakhrutdinov, R M; Falciano, S; Falou, A C; Fang, Y; Fanti, M; Farbin, A; Farilla, A; Farley, J; Farooque, T; Farrington, S M; Farthouat, P; Fasching, D; Fassnacht, P; Fassouliotis, D; Fatholahzadeh, B; Fayard, L; Fazio, S; Febbraro, R; Federic, P; Fedin, O L; Fedorko, I; Fedorko, W; Fehling-Kaschek, M; Feligioni, L; Felzmann, C U; Feng, C; Feng, E J; Fenyuk, A B; Ferencei, J; Ferguson, D; Ferland, J; Fernandes, B; Fernando, W; Ferrag, S; Ferrando, J; Ferrara, V; Ferrari, A; Ferrari, P; Ferrari, R; Ferrer, A; Ferrer, M L; Ferrere, D; Ferretti, C; Ferretto Parodi, A; Ferro, F; Fiascaris, M; Fiedler, F; Filipčič, A; Filippas, A; Filthaut, F; Fincke-Keeler, M; Fiolhais, M C N; Fiorini, L; Firan, A; Fischer, G; Fischer, P; Fisher, M J; Fisher, S M; Flammer, J; Flechl, M; Fleck, I; Fleckner, J; Fleischmann, P; Fleischmann, S; Flick, T; Flores Castillo, L R; Flowerdew, M J; Föhlisch, F; Fokitis, M; Fonseca Martin, T; Fopma, J; Forbush, D A; Formica, A; Forti, A; Fortin, D; Foster, J M; Fournier, D; Foussat, A; Fowler, A J; Fowler, K; Fox, H; Francavilla, P; Franchino, S; Francis, D; Franklin, M; Franz, S; Fraternali, M; Fratina, S; Freestone, J; French, S T; Froeschl, R; Froidevaux, D; Frost, J A; Fukunaga, C; Fullana Torregrosa, E; Fuster, J; Gabaldon, C; Gabizon, O; Gadfort, T; Gadomski, S; Gagliardi, G; Gagnon, P; Galea, C; Gallas, E J; Gallas, M V; Gallo, V; Gallop, B J; Gallus, P; Galyaev, E; Gan, K K; Gao, Y S; Gapienko, V A; Gaponenko, A; Garcia-Sciveres, M; García, C; García Navarro, J E; Gardner, R W; Garelli, N; Garitaonandia, H; Garonne, V; Garvey, J; Gatti, C; Gaudio, G; Gaumer, O; Gautard, V; Gauzzi, P; Gavrilenko, I L; Gay, C; Gaycken, G; Gayde, J-C; Gazis, E N; Ge, P; Gee, C N P; Geich-Gimbel, Ch; Gellerstedt, K; Gemme, C; Genest, M H; Gentile, S; Georgatos, F; George, S; Gerlach, P; Gershon, A; Geweniger, C; Ghazlane, H; Ghez, P; Ghodbane, N; Giacobbe, B; Giagu, S; Giakoumopoulou, V; Giangiobbe, V; Gianotti, F; Gibbard, B; Gibson, A; Gibson, S M; Gieraltowski, G F; Gilbert, L M; Gilchriese, M; Gildemeister, O; Gilewsky, V; Gillberg, D; Gillman, A R; Gingrich, D M; Ginzburg, J; Giokaris, N; Giordani, M P; Giordano, R; Giorgi, F M; Giovannini, P; Giraud, P F; Girtler, P; Giugni, D; Giusti, P; Gjelsten, B K; Gladilin, L K; Glasman, C; Glatzer, J; Glazov, A; Glitza, K W; Glonti, G L; Gnanvo, K G; Godfrey, J; Godlewski, J; Goebel, M; Göpfert, T; Goeringer, C; Gössling, C; Göttfert, T; Goggi, V; Goldfarb, S; Goldin, D; Golling, T; Gollub, N P; Golovnia, S N; Gomes, A; Gomez Fajardo, L S; Gonçalo, R; Gonella, L; Gong, C; Gonidec, A; Gonzalez, S; González de la Hoz, S; Gonzalez Silva, M L; Gonzalez-Pineiro, B; Gonzalez-Sevilla, S; Goodson, J J; Goossens, L; Gorbounov, P A; Gordon, H A; Gorelov, I; Gorfine, G; Gorini, B; Gorini, E; Gorišek, A; Gornicki, E; Gorokhov, S A; Gorski, B T; Goryachev, V N; Gosdzik, B; Gosselink, M; Gostkin, M I; Gouanère, M; Gough Eschrich, I; Gouighri, M; Goujdami, D; Goulette, M P; Goussiou, A G; Goy, C; Grabowska-Bold, I; Grabski, V; Grafström, P; Grah, C; Grahn, K-J; Grancagnolo, F; Grancagnolo, S; Grassi, V; Gratchev, V; Grau, N; Gray, H M; Gray, J A; Graziani, E; Grebenyuk, O G; Green, B; Greenfield, D; Greenshaw, T; Greenwood, Z D; Gregor, I M; Grenier, P; Grewal, A; Griesmayer, E; Griffiths, J; Grigalashvili, N; Grillo, A A; Grimm, K; Grinstein, S; Gris, P L Y; Grishkevich, Y V; Grivaz, J-F; Groer, L S; Grognuz, J; Groh, M; Groll, M; Gross, E; Grosse-Knetter, J; Groth-Jensen, J; Gruwe, M; Grybel, K; Guarino, V J; Guicheney, C; Guida, A; Guillemin, T; Guler, H; Gunther, J; Guo, B; Gupta, A; Gusakov, Y; Gushchin, V N; Gutierrez, A; Gutierrez, P; Guttman, N; Gutzwiller, O; Guyot, C; Gwenlan, C; Gwilliam, C B; Haas, A; Haas, S; Haber, C; Haboubi, G; Hackenburg, R; Hadavand, H K; Hadley, D R; Haeberli, C; Haefner, P; Härtel, R; Hahn, F; Haider, S; Hajduk, Z; Hakobyan, H; Haller, J; Hallewell, G D; Hamacher, K; Hamilton, A; Hamilton, S; Han, H; Han, L; Hanagaki, K; Hance, M; Handel, C; Hanke, P; Hansen, C J; Hansen, J R; Hansen, J B; Hansen, J D; Hansen, P H; Hansl-Kozanecka, T; Hansson, P; Hara, K; Hare, G A; Harenberg, T; Harper, R; Harrington, R D; Harris, O M; Harrison, K; Hart, J C; Hartert, J; Hartjes, F; Haruyama, T; Harvey, A; Hasegawa, S; Hasegawa, Y; Hashemi, K; Hassani, S; Hatch, M; Hauff, D; Haug, S; Hauschild, M; Hauser, R; Havranek, M; Hawes, B M; Hawkes, C M; Hawkings, R J; Hawkins, D; Hayakawa, T; Hayward, H S; Haywood, S J; Hazen, E; He, M; Head, S J; Hedberg, V; Heelan, L; Heim, S; Heinemann, B; Heinemann, F E W; Heisterkamp, S; Helary, L; Heldmann, M; Heller, M; Hellman, S; Helsens, C; Hemperek, T; Henderson, R C W; Hendriks, P J; Henke, M; Henrichs, A; Henriques Correia, A M; Henrot-Versille, S; Henry-Couannier, F; Hensel, C; Henss, T; Hernández Jiménez, Y; Hershenhorn, A D; Herten, G; Hertenberger, R; Hervas, L; Hessey, N P; Hidvegi, A; Higón-Rodriguez, E; Hill, D; Hill, J C; Hill, N; Hiller, K H; Hillert, S; Hillier, S J; Hinchliffe, I; Hindson, D; Hines, E; Hirose, M; Hirsch, F; Hirschbuehl, D; Hobbs, J; Hod, N; Hodgkinson, M C; Hodgson, P; Hoecker, A; Hoeferkamp, M R; Hoffman, J; Hoffmann, D; Hohlfeld, M; Holder, M; Hollins, T I; Hollyman, G; Holmes, A; Holmgren, S O; Holy, T; Holzbauer, J L; Homer, R J; Homma, Y; Horazdovsky, T; Horn, C; Horner, S; Horvat, S; Hostachy, J-Y; Hott, T; Hou, S; Houlden, M A; Hoummada, A; Howell, D F; Hrivnac, J; Hruska, I; Hryn'ova, T; Hsu, P J; Hsu, S-C; Huang, G S; Hubacek, Z; Hubaut, F; Huegging, F; Huffman, T B; Hughes, E W; Hughes, G; Hughes-Jones, R E; Huhtinen, M; Hurst, P; Hurwitz, M; Husemann, U; Huseynov, N; Huston, J; Huth, J; Iacobucci, G; Iakovidis, G; Ibbotson, M; Ibragimov, I; Ichimiya, R; Iconomidou-Fayard, L; Idarraga, J; Idzik, M; Iengo, P; Igonkina, O; Ikegami, Y; Ikeno, M; Ilchenko, Y; Iliadis, D; Imbault, D; Imhaeuser, M; Imori, M; Ince, T; Inigo-Golfin, J; Ioannou, P; Iodice, M; Ionescu, G; Irles Quiles, A; Ishii, K; Ishikawa, A; Ishino, M; Ishmukhametov, R; Isobe, T; Issakov, V; Issever, C; Istin, S; Itoh, Y; Ivashin, A V; Iwanski, W; Iwasaki, H; Izen, J M; Izzo, V; Jackson, B; Jackson, J N; Jackson, P; Jaekel, M R; Jahoda, M; Jain, V; Jakobs, K; Jakobsen, S; Jakubek, J; Jana, D K; Jankowski, E; Jansen, E; Jantsch, A; Janus, M; Jared, R C; Jarlskog, G; Jeanty, L; Jelen, K; Jen-La Plante, I; Jenni, P; Jeremie, A; Jež, P; Jézéquel, S; Ji, H; Ji, W; Jia, J; Jiang, Y; Jimenez Belenguer, M; Jin, G; Jin, S; Jinnouchi, O; Joffe, D; Johansen, L G; Johansen, M; Johansson, K E; Johansson, P; Johnert, S; Johns, K A; Jon-And, K; Jones, G; Jones, M; Jones, R W L; Jones, T W; Jones, T J; Jonsson, O; Joo, K K; Joos, D; Joram, C; Jorge, P M; Jorgensen, S; Joseph, J; Juranek, V; Jussel, P; Kabachenko, V V; Kabana, S; Kaci, M; Kaczmarska, A; Kadlecik, P; Kado, M; Kagan, H; Kagan, M; Kaiser, S; Kajomovitz, E; Kalinin, S; Kalinovskaya, L V; Kama, S; Kanaya, N; Kaneda, M; Kantserov, V A; Kanzaki, J; Kaplan, B; Kapliy, A; Kaplon, J; Kar, D; Karagounis, M; Karagoz, M; Karnevskiy, M; Karr, K; Kartvelishvili, V; Karyukhin, A N; Kashif, L; Kasmi, A; Kass, R D; Kastanas, A; Kastoryano, M; Kataoka, M; Kataoka, Y; Katsoufis, E; Katzy, J; Kaushik, V; Kawagoe, K; Kawamoto, T; Kawamura, G; Kayl, M S; Kayumov, F; Kazanin, V A; Kazarinov, M Y; Kazi, S I; Keates, J R; Keeler, R; Keener, P T; Kehoe, R; Keil, M; Kekelidze, G D; Kelly, M; Kennedy, J; Kenney, C J; Kenyon, M; Kepka, O; Kerschen, N; Kerševan, B P; Kersten, S; Kessoku, K; Ketterer, C; Khakzad, M; Khalil-Zada, F; Khandanyan, H; Khanov, A; Kharchenko, D; Khodinov, A; Kholodenko, A G; Khomich, A; Khoriauli, G; Khovanskiy, N; Khovanskiy, V; Khramov, E; Khubua, J; Kilvington, G; Kim, H; Kim, M S; Kim, P C; Kim, S H; Kimura, N; Kind, O; Kind, P; King, B T; King, M; Kirk, J; Kirsch, G P; Kirsch, L E; Kiryunin, A E; Kisielewska, D; Kisielewski, B; Kittelmann, T; Kiver, A M; Kiyamura, H; Kladiva, E; Klaiber-Lodewigs, J; Klein, M; Klein, U; Kleinknecht, K; Klemetti, M; Klier, A; Klimentov, A; Klingenberg, R; Klinkby, E B; Klioutchnikova, T; Klok, P F; Klous, S; Kluge, E-E; Kluge, T; Kluit, P; Kluth, S; Knecht, N S; Kneringer, E; Knobloch, J; Ko, B R; Kobayashi, T; Kobel, M; Koblitz, B; Kocian, M; Kocnar, A; Kodys, P; Köneke, K; König, A C; Koenig, S; König, S; Köpke, L; Koetsveld, F; Koevesarki, P; Koffas, T; Koffeman, E; Kohn, F; Kohout, Z; Kohriki, T; Koi, T; Kokott, T; Kolachev, G M; Kolanoski, H; Kolesnikov, V; Koletsou, I; Koll, J; Kollar, D; Kollefrath, M; Kolos, S; Kolya, S D; Komar, A A; Komaragiri, J R; Kondo, T; Kono, T; Kononov, A I; Konoplich, R; Konovalov, S P; Konstantinidis, N; Kootz, A; Koperny, S; Kopikov, S V; Korcyl, K; Kordas, K; Koreshev, V; Korn, A; Korol, A; Korolkov, I; Korolkova, E V; Korotkov, V A; Kortner, O; Kostka, P; Kostyukhin, V V; Kotamäki, M J; Kotov, S; Kotov, V M; Kotov, K Y; Kourkoumelis, C; Koutsman, A; Kowalewski, R; Kowalski, H; Kowalski, T Z; Kozanecki, W; Kozhin, A S; Kral, V; Kramarenko, V A; Kramberger, G; Krasel, O; Krasny, M W; Krasznahorkay, A; Kraus, J; Kreisel, A; Krejci, F; Kretzschmar, J; Krieger, N; Krieger, P; Krobath, G; Kroeninger, K; Kroha, H; Kroll, J; Kroseberg, J; Krstic, J; Kruchonak, U; Krüger, H; Krumshteyn, Z V; Kruth, A; Kubota, T; Kuehn, S; Kugel, A; Kuhl, T; Kuhn, D; Kukhtin, V; Kulchitsky, Y; Kuleshov, S; Kummer, C; Kuna, M; Kundu, N; Kunkle, J; Kupco, A; Kurashige, H; Kurata, M; Kurchaninov, L L; Kurochkin, Y A; Kus, V; Kuykendall, W; Kuze, M; Kuzhir, P; Kvasnicka, O; Kwee, R; La Rosa, A; La Rotonda, L; Labarga, L; Labbe, J; Lacasta, C; Lacava, F; Lacker, H; Lacour, D; Lacuesta, V R; Ladygin, E; Lafaye, R; Laforge, B; Lagouri, T; Lai, S; Lamanna, M; Lambacher, M; Lampen, C L; Lampl, W; Lancon, E; Landgraf, U; Landon, M P J; Landsman, H; Lane, J L; Lange, C; Lankford, A J; Lanni, F; Lantzsch, K; Lanza, A; Lapin, V V; Laplace, S; Lapoire, C; Laporte, J F; Lari, T; Larionov, A V; Larner, A; Lasseur, C; Lassnig, M; Lau, W; Laurelli, P; Lavorato, A; Lavrijsen, W; Laycock, P; Lazarev, A B; Lazzaro, A; Le Dortz, O; Le Guirriec, E; Le Maner, C; Le Menedeu, E; Le Vine, M; Leahu, M; Lebedev, A; Lebel, C; Lechowski, M; Lecompte, T; Ledroit-Guillon, F; Lee, H; Lee, J S H; Lee, S C; Lefebvre, M; Legendre, M; Leger, A; Legeyt, B C; Legger, F; Leggett, C; Lehmacher, M; Lehmann Miotto, G; Lehto, M; Lei, X; Leitner, R; Lellouch, D; Lellouch, J; Leltchouk, M; Lendermann, V; Leney, K J C; Lenz, T; Lenzen, G; Lenzi, B; Leonhardt, K; Lepidis, J; Leroy, C; Lessard, J-R; Lesser, J; Lester, C G; Leung Fook Cheong, A; Levêque, J; Levin, D; Levinson, L J; Levitski, M S; Lewandowska, M; Leyton, M; Li, H; Li, X; Liang, Z; Liang, Z; Liberti, B; Lichard, P; Lichtnecker, M; Lie, K; Liebig, W; Lifshitz, R; Lilley, J N; Lim, H; Limosani, A; Limper, M; Lin, S C; Linde, F; Linnemann, J T; Lipeles, E; Lipinsky, L; Lipniacka, A; Liss, T M; Lissauer, D; Lister, A; Litke, A M; Liu, C; Liu, D; Liu, H; Liu, J B; Liu, M; Liu, S; Liu, T; Liu, Y; Livan, M; Livermore, S S A; Lleres, A; Lloyd, S L; Lobodzinska, E; Loch, P; Lockman, W S; Lockwitz, S; Loddenkoetter, T; Loebinger, F K; Loginov, A; Loh, C W; Lohse, T; Lohwasser, K; Lokajicek, M; Loken, J; Long, R E; Lopes, L; Lopez Mateos, D; Losada, M; Loscutoff, P; Losty, M J; Lou, X; Lounis, A; Loureiro, K F; Lovas, L; Love, J; Love, P A; Lowe, A J; Lu, F; Lu, J; Lu, L; Lubatti, H J; Luci, C; Lucotte, A; Ludwig, A; Ludwig, D; Ludwig, I; Ludwig, J; Luehring, F; Luijckx, G; Lumb, D; Luminari, L; Lund, E; Lund-Jensen, B; Lundberg, B; Lundberg, J; Lundquist, J; Lupi, A; Lutz, G; Lynn, D; Lynn, J; Lys, J; Lytken, E; Ma, H; Ma, L L; Maassen, M; Macana Goia, J A; Maccarrone, G; Macchiolo, A; Maček, B; Machado Miguens, J; Macina, D; Mackeprang, R; Macqueen, D; Madaras, R J; Mader, W F; Maenner, R; Maeno, T; Mättig, P; Mättig, S; Magalhaes Martins, P J; Magnoni, L; Magradze, E; Magrath, C A; Mahalalel, Y; Mahboubi, K; Mahmood, A; Mahout, G; Maiani, C; Maidantchik, C; Maio, A; Majewski, S; Makida, Y; Makouski, M; Makovec, N; Mal, P; Malecki, Pa; Malecki, P; Maleev, V P; Malek, F; Mallik, U; Malon, D; Maltezos, S; Malyshev, V; Malyukov, S; Mambelli, M; Mameghani, R; Mamuzic, J; Manabe, A; Manara, A; Mandelli, L; Mandić, I; Mandrysch, R; Maneira, J; Mangeard, P S; Mangin-Brinet, M; Manjavidze, I D; Mann, A; Mann, W A; Manning, P M; Manousakis-Katsikakis, A; Mansoulie, B; Manz, A; Mapelli, A; Mapelli, L; March, L; Marchand, J F; Marchese, F; Marchesotti, M; Marchiori, G; Marcisovsky, M; Marin, A; Marino, C P; Marroquim, F; Marshall, R; Marshall, Z; Martens, F K; Marti-Garcia, S; Martin, A J; Martin, A J; Martin, B; Martin, B; Martin, F F; Martin, J P; Martin, Ph; Martin, T A; Martin Dit Latour, B; Martinez, M; Martinez Outschoorn, V; Martini, A; Martyniuk, A C; Marzano, F; Marzin, A; Masetti, L; Mashimo, T; Mashinistov, R; Masik, J; Maslennikov, A L; Mass, M; Massa, I; Massaro, G; Massol, N; Mastroberardino, A; Masubuchi, T; Mathes, M; Matricon, P; Matsumoto, H; Matsunaga, H; Matsushita, T; Mattravers, C; Maugain, J M; Maxfield, S J; May, E N; Mayer, J K; Mayne, A; Mazini, R; Mazur, M; Mazzanti, M; Mazzoni, E; Mc Donald, J; Mc Kee, S P; McCarn, A; McCarthy, R L; McCarthy, T G; McCubbin, N A; McFarlane, K W; McGarvie, S; McGlone, H; McHedlidze, G; McLaren, R A; McMahon, S J; McMahon, T R; McMahon, T J; McPherson, R A; Meade, A; Mechnich, J; Mechtel, M; Medinnis, M; Meera-Lebbai, R; Meguro, T; Mehdiyev, R; Mehlhase, S; Mehta, A; Meier, K; Meinhardt, J; Meirose, B; Melachrinos, C; Mellado Garcia, B R; Mendoza Navas, L; Meng, Z; Mengarelli, A; Menke, S; Menot, C; Meoni, E; Merkl, D; Mermod, P; Merola, L; Meroni, C; Merritt, F S; Messina, A M; Messmer, I; Metcalfe, J; Mete, A S; Meuser, S; Meyer, C; Meyer, J-P; Meyer, J; Meyer, J; Meyer, T C; Meyer, W T; Miao, J; Michal, S; Micu, L; Middleton, R P; Miele, P; Migas, S; Migliaccio, A; Mijović, L; Mikenberg, G; Mikestikova, M; Mikulec, B; Mikuž, M; Miller, D W; Miller, R J; Mills, W J; Mills, C; Milov, A; Milstead, D A; Milstein, D; Mima, S; Minaenko, A A; Miñano, M; Minashvili, I A; Mincer, A I; Mindur, B; Mineev, M; Ming, Y; Mir, L M; Mirabelli, G; Miralles Verge, L; Misawa, S; Miscetti, S; Misiejuk, A; Mitra, A; Mitrevski, J; Mitrofanov, G Y; Mitsou, V A; Mitsui, S; Miyagawa, P S; Miyazaki, K; Mjörnmark, J U; Mladenov, D; Moa, T; Moch, M; Mockett, P; Moed, S; Moeller, V; Mönig, K; Möser, N; Mohn, B; Mohr, W; Mohrdieck-Möck, S; Moisseev, A M; Moles-Valls, R; Molina-Perez, J; Moneta, L; Monk, J; Monnier, E; Montesano, S; Monticelli, F; Moore, R W; Moorhead, G F; Mora Herrera, C; Moraes, A; Morais, A; Morel, J; Morello, G; Moreno, D; Moreno Llácer, M; Morettini, P; Morgan, D; Morii, M; Morin, J; Morita, Y; Morley, A K; Mornacchi, G; Morone, M-C; Morozov, S V; Morris, J D; Moser, H G; Mosidze, M; Moss, J; Moszczynski, A; Mount, R; Mountricha, E; Mouraviev, S V; Moye, T H; Moyse, E J W; Mudrinic, M; Mueller, F; Mueller, J; Mueller, K; Müller, T A; Muenstermann, D; Muijs, A; Muir, A; Munar, A; Munwes, Y; Murakami, K; Murillo Garcia, R; Murray, W J; Mussche, I; Musto, E; Myagkov, A G; Myska, M; Nadal, J; Nagai, K; Nagano, K; Nagasaka, Y; Nairz, A M; Naito, D; Nakamura, K; Nakano, I; Nanava, G; Napier, A; Nash, M; Nasteva, I; Nation, N R; Nattermann, T; Naumann, T; Nauyock, F; Navarro, G; Nderitu, S K; Neal, H A; Nebot, E; Nechaeva, P; Negri, A; Negri, G; Negroni, S; Nelson, A; Nelson, S; Nelson, T K; Nemecek, S; Nemethy, P; Nepomuceno, A A; Nessi, M; Nesterov, S Y; Neubauer, M S; Neukermans, L; Neusiedl, A; Neves, R M; Nevski, P; Newcomer, F M; Nicholson, C; Nickerson, R B; Nicolaidou, R; Nicolas, L; Nicoletti, G; Nicquevert, B; Niedercorn, F; Nielsen, J; Niinikoski, T; Nikiforov, A; Nikolaenko, V; Nikolaev, K; Nikolic-Audit, I; Nikolopoulos, K; Nilsen, H; Nilsson, P; Ninomiya, Y; Nisati, A; Nishiyama, T; Nisius, R; Nodulman, L; Nomachi, M; Nomidis, I; Nomoto, H; Nordberg, M; Nordkvist, B; Norniella Francisco, O; Norton, P R; Notz, D; Novakova, J; Nozaki, M; Nožička, M; Nugent, I M; Nuncio-Quiroz, A-E; Nunes Hanninger, G; Nunnemann, T; Nurse, E; Nyman, T; O'Neale, S W; O'Neil, D C; O'Shea, V; Oakham, F G; Oberlack, H; Ocariz, J; Ochi, A; Oda, S; Odaka, S; Odier, J; Odino, G A; Ogren, H; Oh, A; Oh, S H; Ohm, C C; Ohshima, T; Ohshita, H; Ohska, T K; Ohsugi, T; Okada, S; Okawa, H; Okumura, Y; Okuyama, T; Olcese, M; Olchevski, A G; Oliveira, M; Oliveira Damazio, D; Oliver, C; Oliver, J; Oliver Garcia, E; Olivito, D; Olszewski, A; Olszowska, J; Omachi, C; Onofre, A; Onyisi, P U E; Oram, C J; Ordonez, G; Oreglia, M J; Orellana, F; Oren, Y; Orestano, D; Orlov, I; Oropeza Barrera, C; Orr, R S; Ortega, E O; Osculati, B; Ospanov, R; Osuna, C; Otero Y Garzon, G; Ottersbach, J P; Ottewell, B; Ouchrif, M; Ould-Saada, F; Ouraou, A; Ouyang, Q; Owen, M; Owen, S; Oyarzun, A; Oye, O K; Ozcan, V E; Ozone, K; Ozturk, N; Pacheco Pages, A; Padilla Aranda, C; Paganis, E; Paige, F; Pajchel, K; Palestini, S; Palla, J; Pallin, D; Palma, A; Palmer, J D; Palmer, M J; Pan, Y B; Panagiotopoulou, E; Panes, B; Panikashvili, N; Panin, V N; Panitkin, S; Pantea, D; Panuskova, M; Paolone, V; Paoloni, A; Papadopoulou, T D; Paramonov, A; Park, S J; Park, W; Parker, M A; Parker, S I; Parodi, F; Parsons, J A; Parzefall, U; Pasqualucci, E; Passeri, A; Pastore, F; Pastore, F; Pásztor, G; Pataraia, S; Patel, N; Pater, J R; Patricelli, S; Pauly, T; Peak, L S; Pecsy, M; Pedraza Morales, M I; Peeters, S J M; Peleganchuk, S V; Peng, H; Pengo, R; Penson, A; Penwell, J; Perantoni, M; Perez, K; Perez Codina, E; Pérez García-Estañ, M T; Perez Reale, V; Peric, I; Perini, L; Pernegger, H; Perrino, R; Perrodo, P; Persembe, S; Perus, P; Peshekhonov, V D; Petereit, E; Peters, O; Petersen, B A; Petersen, J; Petersen, T C; Petit, E; Petridou, C; Petrolo, E; Petrucci, F; Petschull, D; Petteni, M; Pezoa, R; Pfeifer, B; Phan, A; Phillips, A W; Piacquadio, G; Piccaro, E; Piccinini, M; Pickford, A; Piegaia, R; Pilcher, J E; Pilkington, A D; Pina, J; Pinamonti, M; Pinfold, J L; Ping, J; Pinto, B; Pirotte, O; Pizio, C; Placakyte, R; Plamondon, M; Plano, W G; Pleier, M-A; Pleskach, A V; Poblaguev, A; Poddar, S; Podlyski, F; Poffenberger, P; Poggioli, L; Poghosyan, T; Pohl, M; Polci, F; Polesello, G; Policicchio, A; Polini, A; Poll, J; Polychronakos, V; Pomarede, D M; Pomeroy, D; Pommès, K; Ponsot, P; Pontecorvo, L; Pope, B G; Popeneciu, G A; Popescu, R; Popovic, D S; Poppleton, A; Popule, J; Portell Bueso, X; Porter, R; Posch, C; Pospelov, G E; Pospisil, S; Potekhin, M; Potrap, I N; Potter, C J; Potter, C T; Potter, K P; Poulard, G; Poveda, J; Prabhu, R; Pralavorio, P; Prasad, S; Prata, M; Pravahan, R; Pretzl, K; Pribyl, L; Price, D; Price, L E; Price, M J; Prichard, P M; Prieur, D; Primavera, M; Prokofiev, K; Prokoshin, F; Protopopescu, S; Proudfoot, J; Prudent, X; Przysiezniak, H; Psoroulas, S; Ptacek, E; Puigdengoles, C; Purdham, J; Purohit, M; Puzo, P; Pylypchenko, Y; Qi, M; Qian, J; Qian, W; Qian, Z; Qin, Z; Qing, D; Quadt, A; Quarrie, D R; Quayle, W B; Quinonez, F; Raas, M; Radeka, V; Radescu, V; Radics, B; Rador, T; Ragusa, F; Rahal, G; Rahimi, A M; Rahm, D; Raine, C; Raith, B; Rajagopalan, S; Rajek, S; Rammensee, M; Rammes, M; Ramstedt, M; Ratoff, P N; Rauscher, F; Rauter, E; Raymond, M; Read, A L; Rebuzzi, D M; Redelbach, A; Redlinger, G; Reece, R; Reeves, K; Reichold, A; Reinherz-Aronis, E; Reinsch, A; Reisinger, I; Reljic, D; Rembser, C; Ren, Z L; Renkel, P; Rensch, B; Rescia, S; Rescigno, M; Resconi, S; Resende, B; Reznicek, P; Rezvani, R; Richards, A; Richards, R A; Richter, R; Richter-Was, E; Ridel, M; Rieke, S; Rijpstra, M; Rijssenbeek, M; Rimoldi, A; Rinaldi, L; Rios, R R; Riu, I; Rivoltella, G; Rizatdinova, F; Rizvi, E; Roa Romero, D A; Robertson, S H; Robichaud-Veronneau, A; Robinson, D; Robinson, J E M; Robinson, M; Robson, A; Rocha de Lima, J G; Roda, C; Roda Dos Santos, D; Rodier, S; Rodriguez, D; Rodriguez Garcia, Y; Roe, S; Røhne, O; Rojo, V; Rolli, S; Romaniouk, A; Romanov, V M; Romeo, G; Romero Maltrana, D; Roos, L; Ros, E; Rosati, S; Rosenbaum, G A; Rosenberg, E I; Rosendahl, P L; Rosselet, L; Rossetti, V; Rossi, L P; Rossi, L; Rotaru, M; Rothberg, J; Rottländer, I; Rousseau, D; Royon, C R; Rozanov, A; Rozen, Y; Ruan, X; Ruckert, B; Ruckstuhl, N; Rud, V I; Rudolph, G; Rühr, F; Ruggieri, F; Ruiz-Martinez, A; Rulikowska-Zarebska, E; Rumiantsev, V; Rumyantsev, L; Runge, K; Runolfsson, O; Rurikova, Z; Rusakovich, N A; Rust, D R; Rutherfoord, J P; Ruwiedel, C; Ruzicka, P; Ryabov, Y F; Ryadovikov, V; Ryan, P; Rybkin, G; Rzaeva, S; Saavedra, A F; Sadrozinski, H F-W; Sadykov, R; Safai Tehrani, F; Sakamoto, H; Sala, P; Salamanna, G; Salamon, A; Saleem, M; Salihagic, D; Salnikov, A; Salt, J; Saltó Bauza, O; Salvachua Ferrando, B M; Salvatore, D; Salvatore, F; Salvucci, A; Salzburger, A; Sampsonidis, D; Samset, B H; Sandaker, H; Sander, H G; Sanders, M P; Sandhoff, M; Sandhu, P; Sandoval, T; Sandstroem, R; Sandvoss, S; Sankey, D P C; Sanny, B; Sansoni, A; Santamarina Rios, C; Santoni, C; Santonico, R; Santos, H; Saraiva, J G; Sarangi, T; Sarkisyan-Grinbaum, E; Sarri, F; Sartisohn, G; Sasaki, O; Sasaki, T; Sasao, N; Satsounkevitch, I; Sauvage, G; Savard, P; Savine, A Y; Savinov, V; Savva, P; Sawyer, L; Saxon, D H; Says, L P; Sbarra, C; Sbrizzi, A; Scallon, O; Scannicchio, D A; Schaarschmidt, J; Schacht, P; Schäfer, U; Schaetzel, S; Schaffer, A C; Schaile, D; Schaller, M; Schamberger, R D; Schamov, A G; Scharf, V; Schegelsky, V A; Scheirich, D; Schernau, M; Scherzer, M I; Schiavi, C; Schieck, J; Schioppa, M; Schlenker, S; Schlereth, J L; Schmidt, E; Schmidt, M P; Schmieden, K; Schmitt, C; Schmitz, M; Scholte, R C; Schöning, A; Schott, M; Schouten, D; Schovancova, J; Schram, M; Schreiner, A; Schroeder, C; Schroer, N; Schroers, M; Schroff, D; Schuh, S; Schuler, G; Schultes, J; Schultz-Coulon, H-C; Schumacher, J W; Schumacher, M; Schumm, B A; Schune, P; Schwanenberger, C; Schwartzman, A; Schweiger, D; Schwemling, P; Schwienhorst, R; Schwierz, R; Schwindling, J; Scott, W G; Searcy, J; Sedykh, E; Segura, E; Seidel, S C; Seiden, A; Seifert, F; Seixas, J M; Sekhniaidze, G; Seliverstov, D M; Sellden, B; Sellers, G; Seman, M; Semprini-Cesari, N; Serfon, C; Serin, L; Seuster, R; Severini, H; Sevior, M E; Sfyrla, A; Shabalina, E; Shamim, M; Shan, L Y; Shank, J T; Shao, Q T; Shapiro, M; Shatalov, P B; Shaver, L; Shaw, C; Shaw, K; Sherman, D; Sherwood, P; Shibata, A; Shield, P; Shimizu, S; Shimojima, M; Shin, T; Shmeleva, A; Shochet, M J; Shupe, M A; Sicho, P; Sidoti, A; Siebel, A; Siebel, M; Siegert, F; Siegrist, J; Sijacki, D; Silbert, O; Silva, J; Silver, Y; Silverstein, D; Silverstein, S B; Simak, V; Simic, Lj; Simion, S; Simmons, B; Simonyan, M; Sinervo, P; Sinev, N B; Sipica, V; Siragusa, G; Sisakyan, A N; Sivoklokov, S Yu; Sjölin, J; Sjursen, T B; Skinnari, L A; Skovpen, K; Skubic, P; Skvorodnev, N; Slater, M; Slavicek, T; Sliwa, K; Sloan, T J; Sloper, J; Smakhtin, V; Smirnov, S Yu; Smirnov, Y; Smirnova, L N; Smirnova, O; Smith, B C; Smith, D; Smith, K M; Smizanska, M; Smolek, K; Snesarev, A A; Snow, S W; Snow, J; Snuverink, J; Snyder, S; Soares, M; Sobie, R; Sodomka, J; Soffer, A; Solans, C A; Solar, M; Solc, J; Solfaroli Camillocci, E; Solodkov, A A; Solovyanov, O V; Soluk, R; Sondericker, J; Soni, N; Sopko, V; Sopko, B; Sorbi, M; Sosebee, M; Soukharev, A; Spagnolo, S; Spanò, F; Speckmayer, P; Spencer, E; Spighi, R; Spigo, G; Spila, F; Spiriti, E; Spiwoks, R; Spogli, L; Spousta, M; Spreitzer, T; Spurlock, B; St Denis, R D; Stahl, T; Stahlman, J; Stamen, R; Stancu, S N; Stanecka, E; Stanek, R W; Stanescu, C; Stapnes, S; Starchenko, E A; Stark, J; Staroba, P; Starovoitov, P; Stastny, J; Staude, A; Stavina, P; Stavropoulos, G; Steele, G; Stefanidis, E; Steinbach, P; Steinberg, P; Stekl, I; Stelzer, B; Stelzer, H J; Stelzer-Chilton, O; Stenzel, H; Stevenson, K; Stewart, G A; Stiller, W; Stockmanns, T; Stockton, M C; Stodulski, M; Stoerig, K; Stoicea, G; Stonjek, S; Strachota, P; Stradling, A R; Straessner, A; Strandberg, J; Strandberg, S; Strandlie, A; Strang, M; Strauss, M; Strizenec, P; Ströhmer, R; Strom, D M; Strong, J A; Stroynowski, R; Strube, J; Stugu, B; Stumer, I; Sturm, P; Soh, D A; Su, D; Subramania, S; Sugaya, Y; Sugimoto, T; Suhr, C; Suita, K; Suk, M; Sulin, V V; Sultansoy, S; Sumida, T; Sun, X H; Sundermann, J E; Suruliz, K; Sushkov, S; Susinno, G; Sutton, M R; Suzuki, Y; Sviridov, Yu M; Swedish, S; Sykora, I; Sykora, T; Szczygiel, R R; Szeless, B; Szymocha, T; Sánchez, J; Ta, D; Taboada Gameiro, S; Tackmann, K; Taffard, A; Tafirout, R; Taga, A; Takahashi, Y; Takai, H; Takashima, R; Takeda, H; Takeshita, T; Talby, M; Talyshev, A; Tamsett, M C; Tanaka, J; Tanaka, R; Tanaka, S; Tanaka, S; Tanaka, Y; Tani, K; Tappern, G P; Tapprogge, S; Tardif, D; Tarem, S; Tarrade, F; Tartarelli, G F; Tas, P; Tasevsky, M; Tassi, E; Tatarkhanov, M; Taylor, C; Taylor, F E; Taylor, G; Taylor, G N; Taylor, R P; Taylor, W; Teixeira Dias Castanheira, M; Teixeira-Dias, P; Temming, K K; Ten Kate, H; Teng, P K; Tennenbaum-Katan, Y D; Terada, S; Terashi, K; Terron, J; Terwort, M; Testa, M; Teuscher, R J; Tevlin, C M; Thadome, J; Therhaag, J; Theveneaux-Pelzer, T; Thioye, M; Thoma, S; Thomas, J P; Thompson, E N; Thompson, P D; Thompson, P D; Thompson, R J; Thompson, A S; Thomson, E; Thun, R P; Tic, T; Tikhomirov, V O; Tikhonov, Y A; Timmermans, C J W P; Tipton, P; Tique Aires Viegas, F J; Tisserant, S; Tobias, J; Toczek, B; Todorov, T; Todorova-Nova, S; Toggerson, B; Tojo, J; Tokár, S; Tokunaga, K; Tokushuku, K; Tollefson, K; Tomasek, L; Tomasek, M; Tomoto, M; Tompkins, D; Tompkins, L; Toms, K; Tonazzo, A; Tong, G; Tonoyan, A; Topfel, C; Topilin, N D; Torchiani, I; Torrence, E; Torró Pastor, E; Toth, J; Touchard, F; Tovey, D R; Traynor, D; Trefzger, T; Treis, J; Tremblet, L; Tricoli, A; Trigger, I M; Trincaz-Duvoid, S; Trinh, T N; Tripiana, M F; Triplett, N; Trischuk, W; Trivedi, A; Trocmé, B; Troncon, C; Trottier-McDonald, M; Trzupek, A; Tsarouchas, C; Tseng, J C-L; Tsiakiris, M; Tsiareshka, P V; Tsionou, D; Tsipolitis, G; Tsiskaridze, V; Tskhadadze, E G; Tsukerman, I I; Tsulaia, V; Tsung, J-W; Tsuno, S; Tsybychev, D; Tuggle, J M; Turala, M; Turecek, D; Turk Cakir, I; Turlay, E; Tuts, P M; Twomey, M S; Tylmad, M; Tyndel, M; Typaldos, D; Tyrvainen, H; Tzamarioudaki, E; Tzanakos, G; Uchida, K; Ueda, I; Ueno, R; Ugland, M; Uhlenbrock, M; Uhrmacher, M; Ukegawa, F; Unal, G; Underwood, D G; Undrus, A; Unel, G; Unno, Y; Urbaniec, D; Urkovsky, E; Urquijo, P; Urrejola, P; Usai, G; Uslenghi, M; Vacavant, L; Vacek, V; Vachon, B; Vahsen, S; Valderanis, C; Valenta, J; Valente, P; Valentinetti, S; Valkar, S; Valladolid Gallego, E; Vallecorsa, S; Valls Ferrer, J A; Van Berg, R; van der Graaf, H; van der Kraaij, E; van der Poel, E; van der Ster, D; Van Eijk, B; van Eldik, N; van Gemmeren, P; van Kesteren, Z; van Vulpen, I; Vandelli, W; Vandoni, G; Vaniachine, A; Vankov, P; Vannucci, F; Varela Rodriguez, F; Vari, R; Varnes, E W; Varouchas, D; Vartapetian, A; Varvell, K E; Vasilyeva, L; Vassilakopoulos, V I; Vazeille, F; Vegni, G; Veillet, J J; Vellidis, C; Veloso, F; Veness, R; Veneziano, S; Ventura, A; Ventura, D; Ventura, S; Venturi, M; Venturi, N; Vercesi, V; Verducci, M; Verkerke, W; Vermeulen, J C; Vertogardov, L; Vetterli, M C; Vichou, I; Vickey, T; Viehhauser, G H A; Viel, S; Villa, M; Villani, E G; Villaplana Perez, M; Vilucchi, E; Vincter, M G; Vinek, E; Vinogradov, V B; Virchaux, M; Viret, S; Virzi, J; Vitale, A; Vitells, O; Vivarelli, I; Vives Vaque, F; Vlachos, S; Vlasak, M; Vlasov, N; Vogel, A; Vogt, H; Vokac, P; Volpi, M; Volpini, G; von der Schmitt, H; von Loeben, J; von Radziewski, H; von Toerne, E; Vorobel, V; Vorobiev, A P; Vorwerk, V; Vos, M; Voss, R; Voss, T T; Vossebeld, J H; Vovenko, A S; Vranjes, N; Vranjes Milosavljevic, M; Vrba, V; Vreeswijk, M; Vu Anh, T; Vudragovic, D; Vuillermet, R; Vukotic, I; Wagner, W; Wagner, P; Wahlen, H; Walbersloh, J; Walder, J; Walker, R; Walkowiak, W; Wall, R; Waller, P; Wang, C; Wang, H; Wang, J; Wang, J C; Wang, S M; Warburton, A; Ward, C P; Warsinsky, M; Wastie, R; Watkins, P M; Watson, A T; Watson, M F; Watts, G; Watts, S; Waugh, A T; Waugh, B M; Webel, M; Weber, J; Weber, M; Weber, M S; Weber, P; Weidberg, A R; Weingarten, J; Weiser, C; Wellenstein, H; Wellisch, H P; Wells, P S; Wen, M; Wenaus, T; Wendler, S; Weng, Z; Wengler, T; Wenig, S; Wermes, N; Werner, M; Werner, P; Werth, M; Werthenbach, U; Wessels, M; Whalen, K; Wheeler-Ellis, S J; Whitaker, S P; White, A; White, M J; White, S; Whitehead, S R; Whiteson, D; Whittington, D; Wicek, F; Wicke, D; Wickens, F J; Wiedenmann, W; Wielers, M; Wienemann, P; Wiglesworth, C; Wiik, L A M; Wildauer, A; Wildt, M A; Wilhelm, I; Wilkens, H G; Will, J Z; Williams, E; Williams, H H; Willis, W; Willocq, S; Wilson, J A; Wilson, M G; Wilson, A; Wingerter-Seez, I; Winkelmann, S; Winklmeier, F; Wittgen, M; Woehrling, E; Wolter, M W; Wolters, H; Wosiek, B K; Wotschack, J; Woudstra, M J; Wraight, K; Wright, C; Wright, D; Wrona, B; Wu, S L; Wu, X; Wuestenfeld, J; Wulf, E; Wunstorf, R; Wynne, B M; Xaplanteris, L; Xella, S; Xie, S; Xie, Y; Xu, C; Xu, D; Xu, G; Xu, N; Yabsley, B; Yamada, M; Yamamoto, A; Yamamoto, K; Yamamoto, S; Yamamura, T; Yamaoka, J; Yamazaki, T; Yamazaki, Y; Yan, Z; Yang, H; Yang, S; Yang, U K; Yang, Y; Yang, Y; Yang, Z; Yao, W-M; Yao, Y; Yasu, Y; Ye, J; Ye, S; Yilmaz, M; Yoosoofmiya, R; Yorita, K; Yoshida, R; Young, C; Youssef, S P; Yu, D; Yu, J; Yu, J; Yuan, J; Yuan, L; Yurkewicz, A; Zaets, V G; Zaidan, R; Zaitsev, A M; Zajacova, Z; Zalite, Yo K; Zambrano, V; Zanello, L; Zarzhitsky, P; Zaytsev, A; Zdrazil, M; Zeitnitz, C; Zeller, M; Zema, P F; Zemla, A; Zendler, C; Zenin, A V; Zenin, O; Zenis, T; Zenonos, Z; Zenz, S; Zerwas, D; Zevi Della Porta, G; Zhan, Z; Zhang, H; Zhang, J; Zhang, Q; Zhang, X; Zhao, L; Zhao, T; Zhao, Z; Zhemchugov, A; Zheng, S; Zhong, J; Zhou, B; Zhou, N; Zhou, Y; Zhu, C G; Zhu, H; Zhu, Y; Zhuang, X; Zhuravlov, V; Zilka, B; Zimmermann, R; Zimmermann, S; Zimmermann, S; Ziolkowski, M; Zitoun, R; Zivković, L; Zmouchko, V V; Zobernig, G; Zoccoli, A; Zolnierowski, Y; Zsenei, A; Zur Nedden, M; Zutshi, V

2010-10-15

A search for new heavy particles manifested as resonances in two-jet final states is presented. The data were produced in 7 TeV proton-proton collisions by the LHC and correspond to an integrated luminosity of 315  nb⁻¹ collected by the ATLAS detector. No resonances were observed. Upper limits were set on the product of cross section and signal acceptance for excited-quark (q*) production as a function of q* mass. These exclude at the 95% C.L. the q* mass interval 0.30m(q*)<1.26  TeV, extending the reach of previous experiments.

Open Science Grid (OSG) Ticket Synchronization: Keeping Your Home Field Advantage In A Distributed Environment

International Nuclear Information System (INIS)

Gross, Kyle; Hayashi, Soichi; Teige, Scott; Quick, Robert

2012-01-01

Large distributed computing collaborations, such as the Worldwide LHC Computing Grid (WLCG), face many issues when it comes to providing a working grid environment for their users. One of these is exchanging tickets between various ticketing systems in use by grid collaborations. Ticket systems such as Footprints, RT, Remedy, and ServiceNow all have different schema that must be addressed in order to provide a reliable exchange of information between support entities and users in different grid environments. To combat this problem, OSG Operations has created a ticket synchronization interface called GOC-TX that relies on web services instead of error-prone email parsing methods of the past. Synchronizing tickets between different ticketing systems allows any user or support entity to work on a ticket in their home environment, thus providing a familiar and comfortable place to provide updates without having to learn another ticketing system. The interface is built in a way that it is generic enough that it can be customized for nearly any ticketing system with a web-service interface with only minor changes. This allows us to be flexible and rapidly bring new ticket synchronization online. Synchronization can be triggered by different methods including mail, web services interface, and active messaging. GOC-TX currently interfaces with Global Grid User Support (GGUS) for WLCG, Remedy at Brookhaven National Lab (BNL), and Request Tracker (RT) at the Virtual Data Toolkit (VDT). Work is progressing on the Fermi National Accelerator Laboratory (FNAL) ServiceNow synchronization. This paper will explain the problems faced by OSG and how they led OSG to create and implement this ticket synchronization system along with the technical details that allow synchronization to be preformed at a production level.

Open Science Grid (OSG) Ticket Synchronization: Keeping Your Home Field Advantage In A Distributed Environment

Science.gov (United States)

Gross, Kyle; Hayashi, Soichi; Teige, Scott; Quick, Robert

2012-12-01

Large distributed computing collaborations, such as the Worldwide LHC Computing Grid (WLCG), face many issues when it comes to providing a working grid environment for their users. One of these is exchanging tickets between various ticketing systems in use by grid collaborations. Ticket systems such as Footprints, RT, Remedy, and ServiceNow all have different schema that must be addressed in order to provide a reliable exchange of information between support entities and users in different grid environments. To combat this problem, OSG Operations has created a ticket synchronization interface called GOC-TX that relies on web services instead of error-prone email parsing methods of the past. Synchronizing tickets between different ticketing systems allows any user or support entity to work on a ticket in their home environment, thus providing a familiar and comfortable place to provide updates without having to learn another ticketing system. The interface is built in a way that it is generic enough that it can be customized for nearly any ticketing system with a web-service interface with only minor changes. This allows us to be flexible and rapidly bring new ticket synchronization online. Synchronization can be triggered by different methods including mail, web services interface, and active messaging. GOC-TX currently interfaces with Global Grid User Support (GGUS) for WLCG, Remedy at Brookhaven National Lab (BNL), and Request Tracker (RT) at the Virtual Data Toolkit (VDT). Work is progressing on the Fermi National Accelerator Laboratory (FNAL) ServiceNow synchronization. This paper will explain the problems faced by OSG and how they led OSG to create and implement this ticket synchronization system along with the technical details that allow synchronization to be preformed at a production level.

Higgs couplings and supersymmetry in the light of early LHC results

International Nuclear Information System (INIS)

Stefaniak, Tim

2014-07-01

We present phenomenological studies investigating the implications of early results from the Large Hadron Collider (LHC) for models beyond the Standard Model (BSM), mostly focusing on Supersymmetry (SUSY). Our work covers different aspects in this wide field of research. We describe the development and basic concepts of the public computer codes HiggsBounds (version 4) and HiggsSignals. These confront the Higgs sector predictions of BSM models with results from LEP, Tevatron and LHC Higgs searches. While HiggsBounds tests the model against experimental null-results, HiggsSignals evaluates the model's chi-squared compatibility with the signal rate and mass measurements of the Higgs boson, that was discovered by the LHC in 2012. We then perform a systematic study of potential deviations in the Higgs couplings from their Standard Model (SM) prediction. No significant deviations are found. Future capabilities of Higgs coupling determination at the later LHC stages and at the International Linear Collider (ILC) are explored. We also study the implications of the Higgs discovery for the Minimal Supersymmetric Standard Model (MSSM), considering either the light or the heavy CP-even Higgs boson as the discovered state. We show that both interpretations are viable and discuss their phenomenology. Finally, we study the LHC signatures of resonant scalar lepton production, which may arise in SUSY models with R-parity violation (RPV). These are confronted with early LHC results, yielding constraints on the relevant RPV operators.

Pinning synchronization of memristor-based neural networks with time-varying delays.

Science.gov (United States)

Yang, Zhanyu; Luo, Biao; Liu, Derong; Li, Yueheng

2017-09-01

In this paper, the synchronization of memristor-based neural networks with time-varying delays via pinning control is investigated. A novel pinning method is introduced to synchronize two memristor-based neural networks which denote drive system and response system, respectively. The dynamics are studied by theories of differential inclusions and nonsmooth analysis. In addition, some sufficient conditions are derived to guarantee asymptotic synchronization and exponential synchronization of memristor-based neural networks via the presented pinning control. Furthermore, some improvements about the proposed control method are also discussed in this paper. Finally, the effectiveness of the obtained results is demonstrated by numerical simulations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Electronic Systems for the Protection of Superconducting Elements in the LHC

OpenAIRE

Denz, R; Rodríguez-Mateos, F

2004-01-01

This paper gives an overview about the electronic systems used in the protection system for the LHC superconducting elements. The final design of a variety of electronic devices, where the production has recently been launched, is presented and discussed.

Physics perspectives with AFTER@LHC (A Fixed Target ExpeRiment at LHC

Directory of Open Access Journals (Sweden)

Massacrier L.

2018-01-01

Full Text Available AFTER@LHC is an ambitious fixed-target project in order to address open questions in the domain of proton and neutron spins, Quark Gluon Plasma and high-x physics, at the highest energy ever reached in the fixed-target mode. Indeed, thanks to the highly energetic 7 TeV proton and 2.76 A.TeV lead LHC beams, center-of-mass energies as large as sNN = 115 GeV in pp/pA and sNN = 72 GeV in AA can be reached, corresponding to an uncharted energy domain between SPS and RHIC. We report two main ways of performing fixed-target collisions at the LHC, both allowing for the usage of one of the existing LHC experiments. In these proceedings, after discussing the projected luminosities considered for one year of data taking at the LHC, we will present a selection of projections for light and heavy-flavour production.

On the synchronization of a class of chaotic systems based on backstepping method

International Nuclear Information System (INIS)

Wang Bo; Wen Guangjun

2007-01-01

This Letter focuses on the synchronization problem of a class of chaotic systems. A synchronization method is presented based on Lyapunov method and backstepping method. Finally some typical numerical examples are given to show the effectiveness of the theoretical results

Prospects for R-Parity Conserving SUSY searches at the LHC

CERN Document Server

Genest, Marie-Helene

2009-01-01

We review the current strategies to search for generic SUSY models with R-parity conservation in the ATLAS and CMS detectors at the LHC. The discovery reach in early data will be presented for the different search channels based on missing transverse momentum from undetected neutralinos and multiple jets. We will also describe the search for models of gauge-mediated supersymmetry breaking for which the NLSP is a neutralino decaying to a photon and a gravitino. Finally, we will present recent work on techniques used to reconstruct the decays of SUSY particles at the LHC in early data, based on the selection of final-state exclusive decay chains.

Adaptive synchronization of the complex dynamical network with non-derivative and derivative coupling

Energy Technology Data Exchange (ETDEWEB)

Xu Yuhua, E-mail: yuhuaxu2004@163.co [College of Information Science and Technology, Donghua University, Shanghai 201620 (China) and Department of Maths, Yunyang Teachers' College, Hubei 442000 (China); Zhou Wuneng, E-mail: wnzhou@163.co [College of Information Science and Technology, Donghua University, Shanghai 201620 (China); Fang Jian' an [College of Information Science and Technology, Donghua University, Shanghai 201620 (China); Sun Wen [School of Mathematics and Information, Yangtze University, Hubei Jingzhou 434023 (China)

2010-04-05

This Letter investigates the synchronization of a general complex dynamical network with non-derivative and derivative coupling. Based on LaSalle's invariance principle, adaptive synchronization criteria are obtained. Analytical result shows that under the designed adaptive controllers, a general complex dynamical network with non-derivative and derivative coupling can asymptotically synchronize to a given trajectory, and several useful criteria for synchronization are given. What is more, the coupling matrix is not assumed to be symmetric or irreducible. Finally, simulations results show the method is effective.

Sliding mode synchronization controller design with neural network for uncertain chaotic systems

Energy Technology Data Exchange (ETDEWEB)

Mou Chen [College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)], E-mail: chenmou@nuaa.edu.cn; Jiang Changsheng; Bin Jiang; Wu Qingxian [College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

2009-02-28

A sliding mode synchronization controller is presented with RBF neural network for two chaotic systems in this paper. The compound disturbance of the synchronization error system consists of nonlinear uncertainties and exterior disturbances of chaotic systems. Based on RBF neural networks, a compound disturbance observer is proposed and the update law of parameters is given to monitor the compound disturbance. The synchronization controller is given based on the output of the compound disturbance observer. The designed controller can make the synchronization error convergent to zero and overcome the disruption of the uncertainty and the exterior disturbance of the system. Finally, an example is given to demonstrate the availability of the proposed synchronization control method.

A TTC to Data Acquisition interface for the ATLAS Tile Hadronic calorimeter at the LHC

CERN Document Server

Valero, Alberto; The ATLAS collaboration; Torres Pais, Jose Gabriel; Soret Medel, Jesús

2017-01-01

TileCal is the central tile hadronic calorimeter of the ATLAS experiment at the Large Hadron Collider (LHC) at CERN. It is a sampling calorimeter where scintillating tiles are embedded in steel absorber plates. The tiles are read-out using almost 10,000 photomultipliers which convert the light into an electrical signal. These signals are digitized and stored in pipelines memories in the front-end electronics. Upon the reception of a trigger signal, the PMT data is transferred to the Read-Out Drivers in the back-end electronics which process and transmits the processed data to the ATLAS Data AcQuisition (DAQ) system. The Timing, Trigger and Control (TTC) system is an optical network used to distribute the clock synchronized with the accelerator, the trigger signals and configuration commands to both the front-end and back-end electronics components. During physics operation, the TTC system is used to configure the electronics and to distribute trigger information used to synchronize the different parts of the ...

HL-LHC alternatives

CERN Document Server

Tomás, R; White, S

2014-01-01

The HL-LHC parameters assume unexplored regimes for hadron colliders in various aspects of accelerator beam dynamics and technology. This paper reviews three alternatives that could potentially improve the LHC performance: (i) the alternative filling scheme 8b+4e, (ii) the use of a 200 MHz RF system in the LHC and (iii) the use of proton cooling methods to reduce the beam emittance (at top energy and at injection). The alternatives are assessed in terms of feasibility, pros and cons, risks versus benefits and the impact on beam availability.

The super-LHC

CERN Document Server

Mangano, Michelangelo L

2010-01-01

We review here the prospects of a long-term upgrade programme for the Large Hadron Collider (LHC), CERN laboratory's new proton-proton collider. The super-LHC, which is currently under evaluation and design, is expected to deliver of the order of ten times the statistics of the LHC. In addition to a non-technical summary of the principal physics arguments for the upgrade, I present a pedagogical introduction to the technological challenges on the accelerator and experimental fronts, and a review of the current status of the planning.

LHC Supertable

International Nuclear Information System (INIS)

Pereira, M.; Lahey, T.E.; Lamont, M.; Mueller, G.J.; Teixeira, D.D.; McCrory, E.S.

2012-01-01

LHC operations generate enormous amounts of data. This data is being stored in many different databases. Hence, it is difficult for operators, physicists, engineers and management to have a clear view on the overall accelerator performance. Until recently the logging database, through its desktop interface TIMBER, was the only way of retrieving information on a fill-by-fill basis. The LHC Supertable has been developed to provide a summary of key LHC performance parameters in a clear, consistent and comprehensive format. The columns in this table represent main parameters that describe the collider operation such as luminosity, beam intensity, emittance, etc. The data is organized in a tabular fill-by-fill manner with different levels of detail. Particular emphasis was placed on data sharing by making data available in various open formats. Typically the contents are calculated for periods of time that map to the accelerator's states or beam modes such as Injection, Stable Beams, etc. Data retrieval and calculation is triggered automatically after the end of each fill. The LHC Supertable project currently publishes 80 columns of data on around 100 fills. (authors)

Probing dark matter at the LHC using vector boson fusion processes.

Science.gov (United States)

Delannoy, Andres G; Dutta, Bhaskar; Gurrola, Alfredo; Johns, Will; Kamon, Teruki; Luiggi, Eduardo; Melo, Andrew; Sheldon, Paul; Sinha, Kuver; Wang, Kechen; Wu, Sean

2013-08-09

Vector boson fusion processes at the Large Hadron Collider (LHC) provide a unique opportunity to search for new physics with electroweak couplings. A feasibility study for the search of supersymmetric dark matter in the final state of two vector boson fusion jets and large missing transverse energy is presented at 14 TeV. Prospects for determining the dark matter relic density are studied for the cases of wino and bino-Higgsino dark matter. The LHC could probe wino dark matter with mass up to approximately 600 GeV with a luminosity of 1000  fb(-1).

Transport and handling LHC components A permanent challenge

CERN Document Server

Bertone, C

2004-01-01

The LHC project, collider and experiments, is an assembly of thousands of elements, large or small, heavy or light, fragile or robust. Each element has its own transport requirements that constitute a real challenge to handle. Even simple manoeuvres could lead to difficulties in integration, routing and execution due to the complex environment and confined underground spaces. Examples of typical LHC elements transport and handling will be detailed such as the 16-m long, 34-t heavy, fragile cryomagnets from the surface to the final destination in the tunnel, or the delicate cryogenic cold-boxes down to pits and detector components. This challenge did not only require a lot of imagination but also a close cooperation between all the involved parties, in particular with colleagues from safety, cryogenics, civil engineering, integration and logistics.

Multiple types of synchronization analysis for discontinuous Cohen-Grossberg neural networks with time-varying delays.

Science.gov (United States)

Li, Jiarong; Jiang, Haijun; Hu, Cheng; Yu, Zhiyong

2018-03-01

This paper is devoted to the exponential synchronization, finite time synchronization, and fixed-time synchronization of Cohen-Grossberg neural networks (CGNNs) with discontinuous activations and time-varying delays. Discontinuous feedback controller and Novel adaptive feedback controller are designed to realize global exponential synchronization, finite time synchronization and fixed-time synchronization by adjusting the values of the parameters ω in the controller. Furthermore, the settling time of the fixed-time synchronization derived in this paper is less conservative and more accurate. Finally, some numerical examples are provided to show the effectiveness and flexibility of the results derived in this paper. Copyright © 2018 Elsevier Ltd. All rights reserved.

On the Impulsive Synchronization Control for a Class of Chaotic Systems

Directory of Open Access Journals (Sweden)

Bo Wang

2014-01-01

Full Text Available The problem on chaos synchronization for a class of chaotic system is addressed. Based on impulsive control theory and by constructing a novel Lyapunov functional, new impulsive synchronization strategies are presented and possess more practical application value. Finally some typical numerical simulation examples are included to demonstrate the effectiveness of the theoretical results.

The second lightest CP-even Higgs boson signals in the NMSSM at the LHC

Science.gov (United States)

Almarashi, M. M.

2018-04-01

We study the signal rates of the second lightest CP-even Higgs boson, h2, of the NMSSM produced in gluon fusion, in association with bottom quarks and in association with top quarks, which is not the SM-like Higgs boson, at the LHC. We evaluate the production rates of h2 in the SM fermionic and bosonic final states in addition to a1a1, h1h1 and Za1 final states. It is observed that the size of the signal rates in some regions of the NMSSM parameter space is quite large and that could help extracting h2 signals at the LHC through a variety of decay channels.

Generalized Combination Complex Synchronization for Fractional-Order Chaotic Complex Systems

Directory of Open Access Journals (Sweden)

Cuimei Jiang

2015-07-01

Full Text Available Based on two fractional-order chaotic complex drive systems and one fractional-order chaotic complex response system with different dimensions, we propose generalized combination complex synchronization. In this new synchronization scheme, there are two complex scaling matrices that are non-square matrices. On the basis of the stability theory of fractional-order linear systems, we design a general controller via active control. Additionally, by virtue of two complex scaling matrices, generalized combination complex synchronization between fractional-order chaotic complex systems and real systems is investigated. Finally, three typical examples are given to demonstrate the effectiveness and feasibility of the schemes.

The relationship between synchronization and percolation for regular networks

Science.gov (United States)

Li, Zhe; Ren, Tao; Xu, Yanjie; Jin, Jianyu

2018-02-01

Synchronization and percolation are two essential phenomena in complex dynamical networks. They have been studied widely, but previously treated as unrelated. In this paper, the relationship between synchronization and percolation are revealed for regular networks. Firstly, we discovered a bridge between synchronization and percolation by using the eigenvalues of the Laplacian matrix to describe the synchronizability and using the eigenvalues of the adjacency matrix to describe the percolation threshold. Then, we proposed a method to find the relationship for regular networks based on the topology of networks. Particularly, if the degree distribution of the network is subject to delta function, we show that only the eigenvalues of the adjacency matrix need to be calculated. Finally, several examples are provided to demonstrate how to apply our proposed method to discover the relationship between synchronization and percolation for regular networks.

Synchronization in chains of light-controlled oscillators

International Nuclear Information System (INIS)

Avila, G M RamIrez; Guisset, J L; Deneubourg, J L

2005-01-01

Using light-controlled oscillators (LCOs) and a mathematical model of them introduced in [1], we have analyzed a population of LCOs arranged in chains with nonperiodic (linear configuration) and periodic (ring configuration) boundary conditions in which we have solved numerically the corresponding equations for a broad interval of coupling strength values and for chains between 2 and 25 LCOs. We have considered three different situations, viz. identical LCOs, identical LCOs with simplifications (LCOs considered as integrate-and-fire (IF) oscillators), and finally nonidentical LCOs. We study synchronization under two criteria: the first takes into account the simultaneity of flashing events (phase difference criterion), and the second considers period-locking as a criterion for synchronization. For each case, we have identified regions of synchronization in the plane coupling strength versus number of oscillators. We observe different behaviors depending on the values of these variables

HL-LHC updates in Japan

CERN Multimedia

Antonella Del Rosso

2014-01-01

At a recent meeting in Japan, updates on the High Luminosity LHC (HL-LHC) project were presented, including the progress made so far and the deadlines still to be met for the upgraded machine to be operational from 2020.   New magnets made with advanced superconductor Nb3Sn in the framework of the HL-LHC project. These magnets are currently under construction at CERN by the TE-MSC group. The LHC is the world’s most powerful particle accelerator, and in 2015 it will reach yet another new record for the energy of its colliding beams. One key factor of its discovery potential is its ability to produce collisions described in mathematical terms by the parameter known as “luminosity”. In 2025, the HL-LHC project will allow the total number of collisions in the LHC to increase by a factor of 10. The first step in this rich upgrade programme is the delivery of the Preliminary Design Report (PDR), which is also a key milestone of the HiLumi LHC Design Study partly fund...

LS1 Report: the electric atmosphere of the LHC

CERN Multimedia

Simon Baird

2013-01-01

In the LHC, testing of the main magnet (dipole and quadrupole) circuits has been completed. At the same time, the extensive tests of all the other circuits up to current levels corresponding to 7 TeV beam operation have been performed, and now the final ElQA (Electrical Quality Assurance) tests of the electrical circuits are proceeding.   In Sectors 4-5 and 5-6, where the ElQA checks have been finished, the process of removing and storing the helium has started (see the article Heatwave warning for the LHC, in this issue). This is the first step in warming up the whole machine to room temperature so that the main LS1 activities, SMACC (Super Conducting Magnet and Circuit Consolidation) and the R2E (Radiation Two Electronics) programmes, which are scheduled to start on 19 April and 22 March respectively, can get under way. As far as the LHC injectors are concerned, LINAC2 and the PS Booster are in shutdown mode, having completed their preparatory hardware test programmes, and shutdown work has alr...

The TOTEM GEM Telescope (T2) at the LHC

International Nuclear Information System (INIS)

Quinto, M.; Berretti, M.; David, E.; Garcia, F.; Greco, V.; Heino, J.; Hilden, T.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Oliveri, E.; Ropelewski, L.; Scribano, A.; Turini, N.; Stenis, M. van

2011-01-01

The TOTEM T2 telescope will measure inelastically produced charged particles in the forward region of the LHC Interaction Point 5. Each arm of the telescope consists in a set of 20 triple-GEM (Gas Electron Multiplier) detectors with tracking and trigger capabilities. The GEM technology has been considered for the design of TOTEM very forward T2 telescopes thanks to its characteristics: large active areas, good position and timing resolution, excellent rate capability and radiation hardness. Each of the four T2 half arms has been fully assembled and equipped with electronics at CERN and systematically tested in the SPS beam line H8 in 2008/09. After some optimization, the operation of the GEM chambers was fully satisfactory and the T2 telescopes were installed and commissioned in their final positions at the LHC interaction point. During the first LHC run (December 2009) the T2 telescopes have collected data, at 900 GeV and 2.36 TeV. We will present here the performances of the detector and the preliminary results obtained using the data collected.

The TOTEM GEM Telescope (T2) at the LHC

Energy Technology Data Exchange (ETDEWEB)

Quinto, M. [INFN Sezione di Bari, Via E.Orabona n 4, 70126 Bari (Italy); Berretti, M. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); David, E. [CERN, PH Department, 1211 Geneva 23, Geneva (Switzerland); Garcia, F. [University of Helsinki, Institute of Physics and Department of Physical Sciences, Helsinki (Finland); Greco, V. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Heino, J.; Hilden, T.; Kurvinen, K. [University of Helsinki, Institute of Physics and Department of Physical Sciences, Helsinki (Finland); Lami, S. [INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Latino, G. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Lauhakangas, R. [University of Helsinki, Institute of Physics and Department of Physical Sciences, Helsinki (Finland); Oliveri, E. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Ropelewski, L. [CERN, PH Department, 1211 Geneva 23, Geneva (Switzerland); Scribano, A.; Turini, N. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Stenis, M. van [CERN, PH Department, 1211 Geneva 23, Geneva (Switzerland)

2011-06-15

The TOTEM T2 telescope will measure inelastically produced charged particles in the forward region of the LHC Interaction Point 5. Each arm of the telescope consists in a set of 20 triple-GEM (Gas Electron Multiplier) detectors with tracking and trigger capabilities. The GEM technology has been considered for the design of TOTEM very forward T2 telescopes thanks to its characteristics: large active areas, good position and timing resolution, excellent rate capability and radiation hardness. Each of the four T2 half arms has been fully assembled and equipped with electronics at CERN and systematically tested in the SPS beam line H8 in 2008/09. After some optimization, the operation of the GEM chambers was fully satisfactory and the T2 telescopes were installed and commissioned in their final positions at the LHC interaction point. During the first LHC run (December 2009) the T2 telescopes have collected data, at 900 GeV and 2.36 TeV. We will present here the performances of the detector and the preliminary results obtained using the data collected.

LHC luminosity upgrade detector challenges

CERN Multimedia

CERN. Geneva; de Roeck, Albert; Bortoletto, Daniela; Wigmans, Richard; Riegler, Werner; Smith, Wesley H

2006-01-01

LHC luminosity upgrade: detector challenges The upgrade of the LHC machine towards higher luminosity (1035 cm -2s-1) has been studied over the last few years. These studies have investigated scenarios to achieve the increase in peak luminosity by an order of magnitude, as well as the physics potential of such an upgrade and the impact of a machine upgrade on the LHC DETECTORS. This series of lectures will cover the following topics: • Physics motivation and machine scenarios for an order of magnitude increase in the LHC peak luminosity (lecture 1) • Detector challenges including overview of ideas for R&D programs by the LHC experiments: tracking and calorimetry, other new detector developments (lectures 2-4) • Electronics, trigger and data acquisition challenges (lecture 5) Note: the much more ambitious LHC energy upgrade will not be covered

LHC Luminosity Performance

CERN Document Server

AUTHOR|(CDS)2091107; Fuchsberger, Kajetan; Papotti, Giulia

This thesis adresses several approaches with the common goal of assessing, understanding and improving the luminosity of the Large Hadron Collider (LHC). To better exploit existing margins for maximum luminosity while fulfilling the requirements of the LHC experiments, new techniques for luminosity levelling are studied and developed to an operational state, such as changing the crossing angle or $\\beta^*$ (beam size) at the interaction points with the beams in collisions. In 2017 LHC operation, the crossing angle reduction in collisions improved the integrated luminosity by $\\mathrm{\\sim} 2\\,\\mathrm{fb^{-1}}$ ($\\mathrm{\\sim} 4\\,\\mathrm{\\%}$ of the yearly production). For additional diagnostics, a new method for measuring beam sizes and orbits for each circulating bunch using the luminosity measurement during beam separation scans is shown. The results of these Emittance Scans improved the understanding of the LHC luminosity reach and of the orbit offsets introduced by beam-beam long-range effects.

Superconducting magnet tests and measurements for the LHC

International Nuclear Information System (INIS)

Chohan, V.; )

2011-01-01

By end of 2007, the LHC construction, installation and interconnection phases had come to a close with the cooling down of the 8 sectors progressively in 2007-8; the first beams were successfully circulated at injection energies in Sept. 2008 in both rings. For the testing of the 1706 LHC lattice magnets in cryogenic conditions and its successful completion by end 2006, considerable challenges had to be overcome since 2002 to assure certain semi-routine operation at the purpose built tests facility at CERN. In particular, the majority of staff for tests and measurement purposes was provided by India on a rotating, one-year-stay basis, as part of the CERN-India Collaboration for LHC. This was complemented by some CERN accelerator operation staff. From only 95 dipoles tested in year 2003, the completion of tests of all 1706 magnets by early 2007 was made possible by the efforts and innovative ideas in improving and managing the work flow as well as the test rates which came from the Operation team; amongst these, certain novel ideas to stream-line the test procedures as proposed and implemented successfully by the Indian Associates deserve a special mention. This presentation will give an insight to this as well an overall view of the operation related issues in light of different tests and, measurements, constraints and limits. Finally, an indication of how the tests and measurements have contributed to the LHC running will be given. (author)

Chamonix 2016: setting the future course for the LHC and the accelerator complex

CERN Multimedia

Mike Lamont

2016-01-01

The LHC Performance Workshop took place in Chamonix between Tuesday, 25 and Thursday, 28 January. The programme included a review of the machine’s performance in 2015, a forward look at Run 2, and discussion of the status of the LHC injectors upgrade (LIU) and HL-LHC projects. The final session was dedicated to the 2019-2020 long shutdown (LS2).   The 2016 LHC Performance Workshop participants. Last year was the first year of operations following the major maintenance work of the 2013 – 2014 long shutdown (LS1). It was a tough but ultimately successful year. An analysis of operations and efficiency was performed with the aim of identifying possible improvements for 2016. The performance of key systems – e.g. machine protection, collimation, RF, transverse damper, magnetic circuits and beam diagnostics – has been good but nonetheless efforts are still being made to provide, for example, better reliability, improved functionality and monitoring. A number of c...

LHC preparations change gear

International Nuclear Information System (INIS)

Anon.

1995-01-01

After the formal approval by CERN Council in December (January, page 1) of the LHC protonproton collider for CERN's 27- kilometre LEP tunnel, preparations for the new machine change gear. Lyndon Evans becomes LHC Project Leader, and CERN's internal structure will soon be reorganized to take account of the project becoming a definite commitment. On the experimental side, the full Technical Proposals for the big general purpose ATLAS and CMS detectors were aired at a major meeting of the LHC Committee at CERN in January. These Technical Proposals are impressive documents each of some several hundred pages. (Summaries of the detector designs will appear in forthcoming issues of the CERN Courier.) The ALICE heavy ion experiment is not far behind, and plans for other LHC experiments are being developed. Playing an important role in this groundwork has been the Detector Research and Development Committee (DRDC), founded in 1990 to foster detector development for the LHC experimental programme and structured along the lines of a traditional CERN Experiments Committee. Established under the Director Generalship of Carlo Rubbia and initially steered by Research Director Walter Hoogland, the DRDC has done sterling work in blazing a trail for LHC experiments. Acknowledging that the challenge of LHC experimentation needs technological breakthroughs as well as specific detector subsystems, DRDC proposals have covered a wide front, covering readout electronics and computing as well as detector technology. Its first Chairman was Enzo larocci, succeeded in 1993 by Michal Turala. DRDC's role was to evaluate proposals, and make recommendations to CERN's Research Board for approval and resource allocation, not an easy task when the LHC project itself had yet to be formally approved. Over the years, a comprehensive portfolio of detector development has been built up, much of which has either led to specific LHC detector subsystems for traditional detector tasks

First complete NLL BFKL calculation of Mueller Navelet jets at LHC

Energy Technology Data Exchange (ETDEWEB)

Wallon, Samuel [Laboratoire de Physique Theorique d' Orsay - LPT, Bat. 210, Univ. Paris-Sud 11, 91405 Orsay Cedex (France); UPMC Univ. Paris 06 (France); Colferai, Dimitri [Dipartimento di Fisica, Universita di Firenze, Via G. Sansone 1, IT-50019 Firenze (Italy); Istituto Nazionale di Fisica Nucleare - INFN, Sezione di Firenze, Via G.Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Schwennsen, Florian [Deutsches Elektronen-Synchrotron - DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Szymanowski, Lech [Soltan Institute for Nuclear Studies, Hoza 69, 00691, Warsaw (Poland)

2010-07-01

We calculate cross section and azimuthal de-correlation of Mueller Navelet jets at the LHC in the complete next-lo-leading order BFKL framework, i.e. including next-to-leading corrections to the Green's function as well as next-to-leading corrections to the Mueller Navelet vertices. The obtained results for standard observables proposed for studies of Mueller Navelet jets show that both sources of corrections are of equal, big importance for final magnitude and final behavior of observables. The astonishing conclusion of our analysis is that the observables obtained within the complete next-lo-leading order BFKL framework of the present work are quite similar to the same observables obtained within next-to-leading logarithm DGLAP type treatment. This fact sheds doubts on general belief that the studies of Mueller Navelet jets at the LHC will lead to clear discrimination between the BFKL and the DGLAP dynamics. (author)

Status of the 11 T Nb$_{3}$Sn Dipole Project for the LHC

Energy Technology Data Exchange (ETDEWEB)

Savary, F.; et al.

2015-01-01

The planned upgrade of the LHC collimation system includes additional collimators in the LHC lattice. The longitudinal space for the collimators could be obtained by replacing some LHC main dipoles with shorter but stronger dipoles compatible with the LHC lattice and main systems. A joint development program with the goal of building a 5.5 m long two-in-one aperture Nb_3Sn dipole prototype suitable for installation in the LHC is being conducted by FNAL and CERN magnet groups. As part of the first phase of the program, 1 m long and 2 m long single aperture models are being built and tested, and the collared coils from these magnets will be assembled and tested in two-in-one configuration in both laboratories. In parallel with the short model magnet activities, the work has started on the production line in view of the scale-up to 5.5 m long prototype magnet. The development of the final cryo-assembly comprising two 5.5 m long 11 T dipole cold masses and the warm collimator in the middle, fully compatible with the LHC main systems and the existing machine interfaces, has also started at CERN. This paper summarizes the progress made at CERN and FNAL towards the construction of 5.5 m long 11 T Nb_3Sn dipole prototype and the present status of the activities related to the integration of the 11 T dipole and collimator in the LHC.

Finite-Time and Fixed-Time Cluster Synchronization With or Without Pinning Control.

Science.gov (United States)

Liu, Xiwei; Chen, Tianping

2018-01-01

In this paper, the finite-time and fixed-time cluster synchronization problem for complex networks with or without pinning control are discussed. Finite-time (or fixed-time) synchronization has been a hot topic in recent years, which means that the network can achieve synchronization in finite-time, and the settling time depends on the initial values for finite-time synchronization (or the settling time is bounded by a constant for any initial values for fixed-time synchronization). To realize the finite-time and fixed-time cluster synchronization, some simple distributed protocols with or without pinning control are designed and the effectiveness is rigorously proved. Several sufficient criteria are also obtained to clarify the effects of coupling terms for finite-time and fixed-time cluster synchronization. Especially, when the cluster number is one, the cluster synchronization becomes the complete synchronization problem; when the network has only one node, the coupling term between nodes will disappear, and the synchronization problem becomes the simplest master-slave case, which also includes the stability problem for nonlinear systems like neural networks. All these cases are also discussed. Finally, numerical simulations are presented to demonstrate the correctness of obtained theoretical results.

The LHC is safe

CERN Document Server

CERN. Geneva; Alvarez-Gaumé, Luís

2008-01-01

Concerns have been expressed from time to time about the safety of new high-energy colliders, and the LHC has been no exception. The LHC Safety Assessment Group (LSAG)(*) was asked last year by the CERN management to review previous LHC safety analyses in light of additional experimental results and theoretical understanding. LSAG confirms, updates and extends previous conclusions that there is no basis for any conceivable threat from the LHC. Indeed, recent theoretical and experimental developments reinforce this conclusion. In this Colloquium, the basic arguments presented by LSAG will be reviewed. Cosmic rays of much higher effective centre-of-mass energies have been bombarding the Earth and other astronomical objects for billions of years, and their continued existence shows that the Earth faces no dangers from exotic objects such as hypothetical microscopic black holes that might be produced by the LHC - as discussed in a detailed paper by Giddings and Mangano(**). Measurements of strange particle produc...

A word from the DG: LHC commissionning 
enters the home straight

CERN Multimedia

2007-01-01

In an age of blogs there are seemingly no secrets, so by the time Lyn Evans gave his talk on the status of LHC commissioning on 13 September, everyone seemed to know about plug-in modules, beam position monitors and transmitters embedded in ping-pong balls. All the on-line speculation made for interesting reading, and is a clear sign of the growing interest there is in CERN as we approach LHC start-up. We are now entering the final phase of commissioning, and things are going well given the unprecedented complexity of the task in hand. Following the cool-down, powering and warm-up of Sector 7-8 earlier this year, we have learned a great deal about what it means to commission the LHC. There have inevitably been hitches, including the plug-in modules, or PIMs. When the LHC is cooled down, each sector shrinks by about 10 metres in length, and this has to be absorbed by bellows between components and a system of sliding copper fingers (PIM) that ensure electrical connectivity ar...

Thermal Runaway of the 13 kA Busbar Joints in the LHC

CERN Document Server

Verweij, A P

2010-01-01

Triggered by the incident in the LHC in September 2008, the thermo-electrical stability of the 10,000 soldered busbar joints in the 13 kA circuits of the LHC has been re-assessed. For this purpose the computer model QP3 has been developed. In this paper the results of some calculations are presented, and it is shown how the results have been used to improve the quench detection system and ensure safe future operation. First the layout of the 13 kA circuits, the geometry of the soldered joints and the quench detection system will be described. Special focus is put on several types of defects in the joint that have been found in the LHC. The difference between slow and fast thermal run-away will be discussed, focusing on quench propagation and reduced thermal and electrical contacts between the various parts of the joint. It is shown that an enhancement of the LHC quench detection system with a much lower threshold will greatly reduce the risk of burn-out of the joint. Finally it is discussed that protection is...

FPGA Implementation of Burst-Mode Synchronization for SOQSPK-TG

Science.gov (United States)

2014-06-01

is normalized to π. The proposed burst-mode architecture is written in VHDL and verified using Modelsim. The VHDL design is implemented on a Xilinx...Document Number: SET 2014-0043 412TW-PA-14298 FPGA Implementation of Burst-Mode Synchronization for SOQSPK-TG June 2014 Final Report Test...To) 9/11 -- 8/14 4. TITLE AND SUBTITLE FPGA Implementation of Burst-Mode Synchronization for SOQSPK-TG 5a. CONTRACT NUMBER: W900KK-11-C-0032 5b

CMAC-based adaptive backstepping synchronization of uncertain chaotic systems

International Nuclear Information System (INIS)

Lin, C.-M.; Peng, Y.-F.; Lin, M.-H.

2009-01-01

This study proposes an adaptive backstepping control system for synchronizing uncertain chaotic system by using cerebellar model articulation controller (CMAC). CMAC is a nonlinear network with simple computation, good generalization capability and fast learning property. The proposed CMAC-based adaptive backstepping control (CABC) system uses backstepping method and adaptive cerebellar model articulation controller (ACMAC) for synchronizing uncertain chaotic system. Finally, simulation results for the Genesio system are presented to illustrate the effectiveness of the proposed control system.

Non-linear advanced control of the LHC inner triplet heat exchanger test unit

International Nuclear Information System (INIS)

Vinuela, E. Blanco; Cubillos, J. Casas; Prada Moraga, C. de; Cristea, S.

2002-01-01

The future Large Hadron Collider (LHC) at CERN will include eight interaction region final focus magnet systems, the so-called 'Inner Triplet', one on each side of the four beam collision points. The Inner Triplets will be cooled in a static bath of pressurized He II nominally at 1.9 K. This temperature is a control parameter and has very severe constraints in order to avoid the transition from the superconducting to normal resistive state. The main difference in these special zones with respect to a regular LHC cell is higher dynamic heat load unevenly distributed which modifies largely the process characteristics and hence the controller performance. Several control strategies have already been tested at CERN in a pilot plant (LHC String Test) which reproduced a LHC half-cell. In order to validate a common control structure along the whole LHC ring, a Nonlinear Model Predictive Control (NMPC) has been developed and implemented in the Inner Triplet Heat Exchanger Unit (IT-HXTU) at CERN. Automation of the Inner Triplet setup and the advanced control techniques deployed based on the Model Based Predictive Control (MBPC) principle are presented

Upgrade of the ATLAS Hadronic Tile Calorimeter for the High Luminosity LHC

Science.gov (United States)

Tortajada, Ignacio Asensi

2018-01-01

The Large Hadron Collider (LHC) has envisaged a series of upgrades towards a High Luminosity LHC (HL-LHC) delivering five times the LHC nominal instantaneous luminosity. The ATLAS Phase II upgrade, in 2024, will accommodate the upgrade of the detector and data acquisition system for the HL-LHC. The Tile Calorimeter (TileCal) will undergo a major replacement of its on- and off-detector electronics. In the new architecture, all signals will be digitized and then transferred directly to the off-detector electronics, where the signals will be reconstructed, stored, and sent to the first level of trigger at the rate of 40 MHz. This will provide better precision of the calorimeter signals used by the trigger system and will allow the development of more complex trigger algorithms. Changes to the electronics will also contribute to the reliability and redundancy of the system. Three different front-end options are presently being investigated for the upgrade, two of them based on ASICs, and a final solution will be chosen after extensive laboratory and test beam studies that are in progress. A hybrid demonstrator module is being developed using the new electronics while conserving compatibility with the current system. The status of the developments will be presented, including results from the several tests with particle beams.

A Simple Hybrid Synchronization for a Class of Chaotic Financial Systems

Directory of Open Access Journals (Sweden)

Jiming Zheng

2017-01-01

Full Text Available It is an important to achieve the hybrid synchronization of the chaotic financial system. Chaos synchronization is equivalent to the error system which is asymptotically stable. The hybrid synchronization for a class of finance chaotic systems is discussed. First, a simple single variable controller is obtained to synchronize two identical chaotic financial systems with different initial conditions. Second, a novel algorithm is proposed to determine the variables of the master system that should antisynchronize with corresponding variables of the slave system and use this algorithm to determine the corresponding variables in the chaotic financial systems. The hybrid synchronization of the chaotic financial systems is realized by a simple controller. At the same time, different controllers can implement the chaotic financial system hybrid synchronization. In comparison with the existing results, the obtained controllers in this paper are simpler than those of the existing results. Finally, numerical simulations show the effectiveness of the proposed results.

Main improvements of LHC Cryogenics Operation during Run 2 (2015-2018)

Science.gov (United States)

Delprat, L.; Bradu, B.; Brodzinski, K.; Ferlin, G.; Hafi, K.; Herblin, L.; Rogez, E.; Suraci, A.

2017-12-01

After the successful Run 1 (2010-2012), the LHC entered its first Long Shutdown period (LS1, 2013-2014). During LS1 the LHC cryogenic system went under a complete maintenance and consolidation program. The LHC resumed operation in 2015 with an increased beam energy from 4 TeV to 6.5 TeV. Prior to the new physics Run 2 (2015-2018), the LHC was progressively cooled down from ambient to the 1.9 K operation temperature. The LHC has resumed operation with beams in April 2015. Operational margins on the cryogenic capacity were reduced compared to Run 1, mainly due to the observed higher than expected electron-cloud heat load coming from increased beam energy and intensity. Maintaining and improving the cryogenic availability level required the implementation of a series of actions in order to deal with the observed heat loads. This paper describes the results from the process optimization and update of the control system, thus allowing the adjustment of the non-isothermal heat load at 4.5 - 20 K and the optimized dynamic behaviour of the cryogenic system versus the electron-cloud thermal load. Effects from the new regulation settings applied for operation on the electrical distribution feed-boxes and inner triplets will be discussed. The efficiency of the preventive and corrective maintenance, as well as the benefits and issues of the present cryogenic system configuration for Run 2 operational scenario will be described. Finally, the overall availability results and helium management of the LHC cryogenic system during the 2015-2016 operational period will be presented.

LHC status report

CERN Multimedia

CERN Bulletin

2010-01-01

Following the great success of the first 3.5 TeV collisions in all four LHC experiments on 30 March, the focus of the LHC commissioning teams has turned to consolidating the beam injection and acceleration procedures.   During the last two weeks, the operators have adopted a cycle of beam commissioning studies by day and the preparation and delivery of collisions during the night shifts. The injection and acceleration processes for the beams are by now well established and almost all feedback systems, which are an essential ingredient for establishing reliable and safe machine operation, have been commissioned. Thanks to special current settings for the quadrupoles that are situated near the collision points, the LHC luminosity at high energy has been increased by a factor of 5 in three of the four experiments. Similar improvements are under way for the fourth experiment. The next steps include adjustments of the LHC machine protection and collimation devices, which will ensure 'stable beam' co...

Switched generalized function projective synchronization of two identical/different hyperchaotic systems with uncertain parameters

International Nuclear Information System (INIS)

Li Hongmin; Li Chunlai

2012-01-01

In this paper, we investigate two switched synchronization schemes, namely partial and complete switched generalized function projective synchronization, by using the adaptive control method. Partial switched synchronization of chaotic systems means that the state variables of the drive system synchronize with partial different state variables of the response system, whereas complete switched synchronization of chaotic systems means that all the state variables of the drive system synchronize with complete different state variables of the response system. Because the switched synchronization scheme exists in many combinations, it is a promising type of synchronization as it provides greater security in secure communications. Based on the Lyapunov stability theory, the adaptive control laws and the parameter update laws are derived to make the states of two identical/different hyperchaotic systems asymptotically synchronized up to a desired scaling function. Finally, numerical simulations are performed to verify and illustrate the analytical results.

Superconduction in limiting-power synchronous generators. State, lines of development, problems

Energy Technology Data Exchange (ETDEWEB)

Lorenzen, H W; Sergl, J

1976-01-01

The limiting power of conventional 2-pole rotary current synchronous generators is estimated. The limiting power may be raised by using superconducting materials for the field winding. After a short description of superconductive materials, the construction of a synchronous generator with a superconducting field winding is described. Finally, some problems in calculating the magnetic field and the transient behavior are discussed.

Mark the date! LHC inauguration and LHC-Fest CERN, Tuesday 21 October 2008

CERN Document Server

2008-01-01

"For a long time we will remember the year 2008, an important year for CERN. as it marks the achievement of the LHC, a great tool for future discoveries, and the completion of exceptional works that demanded the commitment and motivation of many… a remarkable motivation," declared Director-General Robert Aymar during a recent interview. To celebrate this historical milestone in this very important "Big Science" project, CERN has organised two events on October 21: the LHC official inauguration and the LHC-fest. The LHC official inauguration will take place from 14h00 to 18h00, at Point 18 of the Laboratory, in the presence of the highest representatives from the member states of CERN and representatives from the other communities and authorities of the countries participating in the LHC adventure. 300 members from the international press are also expected, giving a total of 1500 guests. The ceremony will be broadcast live in the Lab...

Chaos synchronization communication using extremely unsymmetrical bidirectional injections.

Science.gov (United States)

Zhang, Wei Li; Pan, Wei; Luo, Bin; Zou, Xi Hua; Wang, Meng Yao; Zhou, Zhi

2008-02-01

Chaos synchronization and message transmission between two semiconductor lasers with extremely unsymmetrical bidirectional injections (EUBIs) are discussed. By using EUBIs, synchronization is realized through injection locking. Numerical results show that if the laser subjected to strong injection serves as the receiver, chaos pass filtering (CPF) of the system is similar to that of unidirectional coupled systems. Moreover, if the other laser serves as the receiver, a stronger CPF can be obtained. Finally, we demonstrate that messages can be extracted successfully from either of the two transmission directions of the system.

The LHC at level best

CERN Multimedia

Katarina Anthony

2013-01-01

On 10 March, a team of CERN surveyors descended into the LHC tunnel. Their aim: to take measurements of the height of the LHC magnets to see how geological shifts might be affecting the machine and to take reference positions of the machine before the interconnects are opened.    CERN surveyors take levelling measurements of the LHC magnets during LS1. The LHC tunnel is renowned for its geological stability: set between layers of sandstone and molasse, it has allowed the alignment of the world’s largest accelerators to be within sub-millimetre precision. But even the most stable of tunnels can be affected by geological events. To ensure the precise alignment of the LHC, the CERN survey team performs regular measurements of the vertical position of the magnets (a process known as “levelling”). Over the past month, the team has been taking measurements of the LHC before the temperature of the magnets reaches 100 K, beyond which there may be some mechanic...

The High Luminosity LHC Project

Science.gov (United States)

Rossi, Lucio

The High Luminosity LHC is one of the major scientific project of the next decade. It aims at increasing the luminosity reach of LHC by a factor five for peak luminosity and a factor ten in integrated luminosity. The project, now fully approved and funded, will be finished in ten years and will prolong the life of LHC until 2035-2040. It implies deep modifications of the LHC for about 1.2 km around the high luminosity insertions of ATLAS and CMS and relies on new cutting edge technologies. We are developing new advanced superconducting magnets capable of reaching 12 T field; superconducting RF crab cavities capable to rotate the beams with great accuracy; 100 kA and hundred meter long superconducting links for removing the power converter out of the tunnel; new collimator concepts, etc... Beside the important physics goals, the High Luminosity LHC project is an ideal test bed for new technologies for the next hadron collider for the post-LHC era.

Synchronization of metronomes

Science.gov (United States)

Pantaleone, James

2002-10-01

Synchronization is a common phenomenon in physical and biological systems. We examine the synchronization of two (and more) metronomes placed on a freely moving base. The small motion of the base couples the pendulums causing synchronization. The synchronization is generally in-phase, with antiphase synchronization occurring only under special conditions. The metronome system provides a mechanical realization of the popular Kuramoto model for synchronization of biological oscillators, and is excellent for classroom demonstrations and an undergraduate physics lab.

QCD in gauge-boson production at the LHC

CERN Document Server

Schott, Matthias; The ATLAS collaboration

2018-01-01

Measurements of the Drell-Yan production of W and Z/gamma* bosons at the LHC provide a benchmark of our understanding of perturbative QCD and probe the proton structure in a unique way. The ATLAS and CMS collaborations have performed several high precision measurements at different center-of-mass energies, ranging from single to triple differential cross sections. These measurements are the key in improving physics modelling uncertainties of electroweak precision measurements at the LHC. Moreover, perturbative QCD can be tested further in a multi-scale environment, when studying the production of jets in association with single and di-bosons final states. In this talk, we review the latest measurements, discuss the compatibility between the experiments and compare the results to the state-of-the-art QCD calculations and Monte Carlo simulations, as well their potential impact on improving our understanding PDFs.

LHC Commissioning and First Operation

OpenAIRE

Myers, S

2010-01-01

A description is given of the repair of the LHC after the accident of September 2008. The LHC hardware and beam commissioning and initial operation are reviewed both in terms of beam and hardware performance. The implemented machine protection measures and their impact on LHC operation are presented.

Support for the LHC experiments

CERN Document Server

Butin, François; Gastal, M; Lacarrère, D; Macina, D; Perrot, A L; Tsesmelis, E; Wilhelmsson, M; CERN. Geneva. TS Department

2008-01-01

Experimental Area Teams have been put in place and charged with the general co-ordination and management of the LHC experimental areas and of the zones in the LHC tunnel hosting near-beam detectors of the experiments. This organization is responsible for the in situ co-ordination of work with the aim of providing a structure that enables the experiment collaborations and accelerator groups to carry out their work effectively and safely. This presentation will review some key elements in the support given to the LHC experimental areas and, given the track record and successful implementation during the LHC installation and commissioning phase, will argue that such an organization structure will be required also for the period of LHC exploitation for physics.

Large Cryogenic Infrastructure for LHC Superconducting Magnet and Cryogenic Component Tests: Layout, Commissioning and Operational Experience

International Nuclear Information System (INIS)

Calzas, C.; Chanat, D.; Knoops, S.; Sanmarti, M.; Serio, L.

2004-01-01

The largest cryogenic test facility at CERN, located at Zone 18, is used to validate and to test all main components working at cryogenic temperature in the LHC (Large Hadron Collider) before final installation in the machine tunnel. In total about 1300 main dipoles, 400 main quadrupoles, 5 RF-modules, eight 1.8 K refrigeration units will be tested in the coming years.The test facility has been improved and upgraded over the last few years and the first 18 kW refrigerator for the LHC machine has been added to boost the cryogenic capacity for the area via a 25,000 liter liquid helium dewar. The existing 6 kW refrigerator, used for the LHC Test String experiments, will also be employed to commission LHC cryogenic components.We report on the design and layout of the test facility as well as the commissioning and the first 10,000 hours operational experience of the test facility and the 18 kW LHC refrigerator

Modelling and Measurements of Bunch Profiles at the LHC Flat Bottom

CERN Document Server

Papadopoulou, Stefania; Muller, Juan; Papaphilippou, Yannis; Trad, Georges

2016-01-01

At the LHC flat bottom the interplay between a series of effects (i.e. intrabeam scattering, longitudinal beam manipulations, non-linearities of the machine, etc) can lead to a population of the tails of the beam distributions, which may become non-Gaussian. This paper presents observations of the evolution of particle distributions in the LHC flat bottom. Novel distribution functions are employed to represent the beam profiles, and used as a guideline for generalising emittance growth rate estimations due to IBS. Finally, an attempt is made to benchmark an IBS Monte-Carlo simulation code, able to track 3D particle distributions, with the measured beam profile evolutions.

Fixed-Time Stability Analysis of Permanent Magnet Synchronous Motors with Novel Adaptive Control

Directory of Open Access Journals (Sweden)

Maoxing Liu

2017-01-01

Full Text Available We firstly investigate the fixed-time stability analysis of uncertain permanent magnet synchronous motors with novel control. Compared with finite-time stability where the convergence rate relies on the initial permanent magnet synchronous motors state, the settling time of fixed-time stability can be adjusted to desired values regardless of initial conditions. Novel adaptive stability control strategy for the permanent magnet synchronous motors is proposed, with which we can stabilize permanent magnet synchronous motors within fixed time based on the Lyapunov stability theory. Finally, some simulation and comparison results are given to illustrate the validity of the theoretical results.

Physics Validation of the LHC Software

CERN Multimedia

CERN. Geneva

2004-01-01

The LHC Software will be confronted to unprecedented challenges as soon as the LHC will turn on. We summarize the main Software requirements coming from the LHC detectors, triggers and physics, and we discuss several examples of Software components developed by the experiments and the LCG project (simulation, reconstruction, etc.), their validation, and their adequacy for LHC physics.

From lag synchronization to pattern formation in one-dimensional open flow models

International Nuclear Information System (INIS)

Liu Zengrong; Luo Jigui

2006-01-01

In this paper, the relation between synchronization and pattern formation in one-dimensional discrete and continuous open flow models is investigated in detail. Firstly a sufficient condition for globally asymptotical stability of lag/anticipating synchronization among lattices of these models is proved by analytic method. Then, by analyzing and simulating lag/anticipating synchronization in discrete case, three kinds of pattern of wave (it is called wave pattern) travelling in the lattices are discovered. Finally, a proper definition for these kinds of pattern is proposed

The LHC

CERN Multimedia

2002-01-01

The LHC will use the latest technologies on an enormous scale. 8000 superconducting magnets will keep the beams on track. The entire 27 km ring will be cooled by 700 000 litres of liquid helium to a temperature of -271 degrees Celsius , making the LHC the world's largest superconducting installation. Conventional superconducting wire will form the magnet coils, while high-temperature superconductors will carry a total of 2 300 000 amperes from the power supplies into the magnet cryostat

Synchronous and Cogged Fan Belt Performance Assessment

Energy Technology Data Exchange (ETDEWEB)

Cutler, Dylan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dean, Jesse [National Renewable Energy Lab. (NREL), Golden, CO (United States); Acosta, Jason [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2014-02-01

The GSA Regional GPG Team commissioned the National Renewable Energy Laboratory (NREL) to perform monitoring of cogged V-belts and synchronous belts on both a constant volume and a variable air volume fan at the Byron G. Rodgers Federal Building and U.S. Courthouse in Denver, Colorado. These motor/fan combinations were tested with their original, standard V-belts (appropriately tensioned by an operation and maintenance professional) to obtain a baseline for standard operation. They were then switched to the cogged V-belts, and finally to synchronous belts. The power consumption by the motor was normalized for both fan speed and air density changes. This was necessary to ensure that the power readings were not influenced by a change in rotational fan speed or by the power required to push denser air. Finally, energy savings and operation and maintenance savings were compiled into an economic life-cycle cost analysis of the different belt options.

Installation of the LHC transfer lines begins

CERN Multimedia

Patrice Loïez

2003-01-01

The first of 700 magnets has been installed in one of the two transfer tunnels built to transfer the SPS beam into the LHC. The start of this first installation phase of the LHC transfer lines provides the opportunity to launch a new and highly original modular system for transporting and installing all kinds of magnets in very narrow tunnels. The system is based on very compact bogies, up to four of which can be coupled together to form a convoy. The wheels are fitted with individual motors enabling them to swivel through an angle of 90° and the convoy to move laterally. In this way the magnet is delivered directly to its installation point, but beneath the beamline. It is then raised into its final position in the beamline using air cushions, which form an integrated part of the transport system. Here we see the transport vehicle alongside the magnet supports. Visible in the background is the first magnet in place.

The Mechanical Design for the LHC Collimators

CERN Document Server

Bertarelli, A; Assmann, R W; Chiaveri, Enrico; Kurtyka, T; Mayer, M; Perret, R; Sievers, P

2004-01-01

The design of the LHC collimators must comply with the very demanding specifications entailed by the highly energetic beam handled in the LHC: these requirements impose a temperature on the collimating jaws not exceeding 50ºC in steady operations and an unparalleled overall geometrical stability of 25 micro-m on a 1200 mm span. At the same time, the design phase must meet the challenging deadlines required by the general time schedule. To respond to these tough and sometimes conflicting constraints, the chosen design appeals to a mixture of traditional and innovative technologies, largely drawing from LEP collimator experience. The specifications impose a low-Z material for the collimator jaws, directing the design towards such graphite or such novel materials as 3-d Carbon/carbon composites. An accurate mechanical design has allowed to considerably reduce mechanical play and optimize geometrical stability. Finally, all mechanical studies were supported by in-depth thermo-mechanical analysis concerning tempe...

PC as physics computer for LHC?

International Nuclear Information System (INIS)

Jarp, Sverre; Simmins, Antony; Tang, Hong

1996-01-01

In the last five years, we have seen RISC workstations take over the computing scene that was once controlled by mainframes and supercomputers. In this paper we will argue that the same phenomenon might happen again. A project, active since March this year in the Physics Data Processing group of CERN's CN division is described where ordinary desktop PCs running Windows (NT and 3.11) have been used for creating an environment for running large LHC batch jobs (initially the DICE simulation job of Atlas). The problems encountered in porting both the CERN library and the specific Atlas codes are described together with some encouraging benchmark results when comparing to existing to existing RISC workstation in use by the Atlas collaboration. The issues of establishing the batch environment (Batch monitor, staging software, etc) are also covered. Finally a quick extrapolation of commodity computing power available in the future is touched upon to indicate what kind of cost envelope could be sufficient for the simulation farms required by the LHC experiments. (author)

All systems go for LHC quadrupoles

CERN Multimedia

2003-01-01

The series fabrication of the Main Quadrupole cold masses for the LHC has begun with the delivery of the first unit on February 12th. The superconducting dipole magnets required to bend the proton beams around the LHC are often in the news. Less famous, perhaps, but equally important are the 360 main quadrupole (MQ) magnets, which will perform the principal focusing around the 27 km ring. CERN and CEA-Saclay began collaborating on the development and prototyping of these magnets in 1989. This resulted in five highly successful quadrupole units - also known as short straight sections - one of which was integrated for testing in String 1, and two others of the final design in String 2. Once the tests had confirmed the validity of the design and realization, the fabrication of the 360 cold masses had to be transferred to industry. After highly competitive tendering, the German firm ACCEL Instruments was entrusted both with the construction of the quadrupole magnets themselves, and with their assembly into the co...

LHC Report: Steady as she goes

CERN Multimedia

Mike Lamont for the LHC Team

2011-01-01

Despite the usual ups and downs, over the last fortnight the LHC has succeeded in delivering of the order of 500 inverse picobarns a week. The machine parameters are now at 1380 bunches, 1.3x1011 protons per bunch, and using the smallest possible beam sizes that the SPS can currently produce. These settings, together with the 1 m ß* squeeze, have allowed ATLAS and CMS to receive over 10 inverse picobarns an hour at the start of a fill.   "We'll miss you." The Tevatron was given a final salute on the LHC1 screen on 30 September 2011, the day of its shutdown. There is a little over three weeks to the end of this year's proton run and the operations team is trying to squeeze in a number of special runs for dedicated studies. These include testing the machine with a beam with a 25 ns bunch spacing (which would open the way to doubling the number of bunches), and performing a high "pile-up" run in which single bunches with maximum int...

Very forward measurements at the LHC

CERN Document Server

Berretti, Mirko

2017-01-01

In this talk we present a selection of forward physics results recently obtained with the run-1 and run-2 LHC data by the CMS, LHCf and TOTEM experiments. The status of the very forward LHC proton spectrometer, CT-PPS, is discussed: emphasis is given to the physics potential of CT-PPS and to the analyses that are currently ongoing with the data collected in 2016. Very recent forward measurements obtained with the LHCf and the CMS-CASTOR calorimeter are then addressed. In particular, CMS measured the inclusive energy spectrum in the very forward direction for proton-proton collisions at a center-of-mass energy of 13 TeV and the jet cross sections for p+Pb collisions at 5.02 TeV. The LHCf experiment has instead recently published the inclusive energy spectra of forward photons for pp collisions at 13 TeV. Finally, the new measurements of the total, elastic and inelastic cross sections obtained by the TOTEM collaboration at 2.76 and 13 TeV center of mass energy are presented.

Pc as Physics Computer for Lhc ?

Science.gov (United States)

Jarp, Sverre; Simmins, Antony; Tang, Hong; Yaari, R.

In the last five years, we have seen RISC workstations take over the computing scene that was once controlled by mainframes and supercomputers. In this paper we will argue that the same phenomenon might happen again. A project, active since March this year in the Physics Data Processing group, of CERN's CN division is described where ordinary desktop PCs running Windows (NT and 3.11) have been used for creating an environment for running large LHC batch jobs (initially the DICE simulation job of Atlas). The problems encountered in porting both the CERN library and the specific Atlas codes are described together with some encouraging benchmark results when comparing to existing RISC workstations in use by the Atlas collaboration. The issues of establishing the batch environment (Batch monitor, staging software, etc.) are also covered. Finally a quick extrapolation of commodity computing power available in the future is touched upon to indicate what kind of cost envelope could be sufficient for the simulation farms required by the LHC experiments.

Physics possibilities at LHC/SSC

International Nuclear Information System (INIS)

Hinchliffe, I.

1991-01-01

This document reviews some recent work on physics simulations for SSC/LHC. Included are reviews of some of the recent developments in physics simulations for the SSC/LHC and comments upon the requirements that are placed upon detectors by the need to extract specific physics signatures. The material in the various EOI/LOI documents submitted to the SCC Laboratory and the work done at the Aachen LHC workshop are discussed. In the following discussion 1 SSC (LHC) year corresponds to an integrated luminosity of 10 (100) fb -1 . 41 refs., 14 figs

Global impulsive exponential synchronization of stochastic perturbed chaotic delayed neural networks

International Nuclear Information System (INIS)

Hua-Guang, Zhang; Tie-Dong, Ma; Jie, Fu; Shao-Cheng, Tong

2009-01-01

In this paper, the global impulsive exponential synchronization problem of a class of chaotic delayed neural networks (DNNs) with stochastic perturbation is studied. Based on the Lyapunov stability theory, stochastic analysis approach and an efficient impulsive delay differential inequality, some new exponential synchronization criteria expressed in the form of the linear matrix inequality (LMI) are derived. The designed impulsive controller not only can globally exponentially stabilize the error dynamics in mean square, but also can control the exponential synchronization rate. Furthermore, to estimate the stable region of the synchronization error dynamics, a novel optimization control algorithm is proposed, which can deal with the minimum problem with two nonlinear terms coexisting in LMIs effectively. Simulation results finally demonstrate the effectiveness of the proposed method

LHC challenges and upgrade options

Energy Technology Data Exchange (ETDEWEB)

Bruning, O [CERN AB/ABP, Y03600, 1211 Geneva 23 (Switzerland)], E-mail: Oliver.Bruning@cern.ch

2008-05-15

The presentation summarizes the key parameters of the LHC collider. Following a discussion of the main challenges for reaching the nominal machine performance the presentation identifies options for increasing the operation tolerances and the potential performance reach of the LHC by means of future hardware upgrades of the LHC and its injector complex.

LHC challenges and upgrade options

International Nuclear Information System (INIS)

Bruning, O

2008-01-01

The presentation summarizes the key parameters of the LHC collider. Following a discussion of the main challenges for reaching the nominal machine performance the presentation identifies options for increasing the operation tolerances and the potential performance reach of the LHC by means of future hardware upgrades of the LHC and its injector complex

FEM Analysis of Beam-coupling Impedance and RF Contacts Criticality on the LHC UA9 Piezo Goniometer

CERN Document Server

Danisi, A; Passarelli, A; Masi, A; Losito, R; Salvant, B

2014-01-01

The UA9 piezo-goniometer has been designed to guarantee micro-radians-accuracy angular positioning of a silicon crystal for a crystal collimation experiment in the LHC, and to minimize the impact on the LHC beam coupling impedance. This paper presents a Finite Element Method (FEM) study of the device, in both parking and operational positions, to evaluate its impact on the LHC impedance budget. In addition, the shielding contribution of the RF gaskets has been carefully evaluated, with the objective to assess the consequences for operation in case of their failure. A final word is drawn on the overall device impedance criticality.

Adaptive Synchronization of Chaotic Systems considering Performance Parameters of Operational Amplifiers

Directory of Open Access Journals (Sweden)

Sergio Ruíz-Hernández

2015-01-01

Full Text Available This paper addresses an adaptive control approach for synchronizing two chaotic oscillators with saturated nonlinear function series as nonlinear functions. Mathematical models to characterize the behavior of the transmitter and receiver circuit were derived, including in the latter the adaptive control and taking into account, for both chaotic oscillators, the most influential performance parameters associated with operational amplifiers. Asymptotic stability of the full synchronization system is studied by using Lyapunov direct method. Theoretical derivations and related results are experimentally validated through implementations from commercially available devices. Finally, the full synchronization system can easily be reproducible at a low cost.

On adaptive modified projective synchronization of a supply chain management system

Science.gov (United States)

Tirandaz, Hamed

2017-12-01

In this paper, the synchronization problem of a chaotic supply chain management system is studied. A novel adaptive modified projective synchronization method is introduced to control the behaviour of the leader supply chain system by a follower chaotic system and to adjust the leader system parameters until the measurable errors of the system parameters converge to zero. The stability evaluation and convergence analysis are carried out by the Lyapanov stability theorem. The proposed synchronization and antisynchronization techniques are studied for identical supply chain chaotic systems. Finally, some numerical simulations are presented to verify the effectiveness of the theoretical discussions.

Fully transparent LHC

CERN Multimedia

2008-01-01

Thanks to the first real signals received from the LHC while in operation before the incident, the experiments are now set to make the best use of the data they have collected. Report from the LHCC open session.The September open session of the LHCC (LHC Experiments Committee) came just a few days after the incident that occurred at the LHC. The packed auditorium was a testament to the huge interest raised by Lyn Evans’ talk about the status of the machine and the plans for the future. After being told that the actual consequences of the incident will be clear only once Sector 3-4 has been warmed up, the audience focussed on the reports from the experiments. For the first time, the reports showed performance results of the various detectors with particles coming from the machine and not just from cosmic rays or tests and simulations. "The first days of LHC beam exceeded all expectations and the experiments made extensive and rapid use of the data they collected", says ...

The whole world behind the LHC

CERN Multimedia

2001-01-01

The LHC Board, which includes representatives of the non-Member State organisations directly involved in the construction of the LHC accelerator and representatives of CERN, held its fourth meeting on Monday 21 May 2001. From left to right: 1st row, A. Yamamoto (KEK, Japan), P. Pfund (FNAL, United States), L. Maiani (CERN Director-General), L. Evans (LHC Project Leader), F. Dupont (IN2P3, France), D.D. Bhawalkar (CAT, India) ; 2nd row, P. Brossier (CEA, France), N. Tyurin (IHEP, Russia), A. Skrinsky (BINP, Russia), A. Astbury (TRIUMF, Canada), P. Lebrun (LHC Division Leader, CERN); 3rd row, T. Taylor (Deputy Division Leader LHC Division, CERN), A. Shotter (TRIUMF, Canada), P. Bryant (LHC, CERN), K. Hübner (Director for Accelerators, CERN), J. van der Boon (Director of Administration, CERN). Although Canada, the United States, India, Japan and the Russian Federation are not members of CERN, they are all playing an active part in the construction of the LHC through important technical and financial co...

LHC Accelerator Fault Tracker - First Experience

CERN Document Server

Apollonio, Andrea; Roderick, Chris; Schmidt, Ruediger; Todd, Benjamin; Wollmann, Daniel

2016-01-01

Availability is one of the key performance indicators of LHC operation, being directly correlated with integrated luminosity production. An effective tool for availability tracking is a necessity to ensure a coherent capture of fault information and relevant dependencies on operational modes and beam parameters. At the beginning of LHC Run 2 in 2015, the Accelerator Fault Tracking (AFT) tool was deployed at CERN to track faults or events affecting LHC operation. Information derived from the AFT is crucial for the identification of areas to improve LHC availability, and hence LHC physics production. For the 2015 run, the AFT has been used by members of the CERN Availability Working Group, LHC Machine coordinators and equipment owners to identify the main contributors to downtime and to understand the evolution of LHC availability throughout the year. In this paper the 2015 experience with the AFT for availability tracking is summarised and an overview of the first results as well as an outlook to future develo...

Exponential synchronization of complex networks with nonidentical time-delayed dynamical nodes

International Nuclear Information System (INIS)

Cai Shuiming; He Qinbin; Hao Junjun; Liu Zengrong

2010-01-01

In this Letter, exponential synchronization of a complex network with nonidentical time-delayed dynamical nodes is considered. Two effective control schemes are proposed to drive the network to synchronize globally exponentially onto any smooth goal dynamics. By applying open-loop control to all nodes and adding some intermittent controllers to partial nodes, some simple criteria for exponential synchronization of such network are established. Meanwhile, a pinning scheme deciding which nodes need to be pinned and a simply approximate formula for estimating the least number of pinned nodes are also provided. By introducing impulsive effects to the open-loop controlled network, another synchronization scheme is developed for the network with nonidentical time-delayed dynamical nodes, and an estimate of the upper bound of impulsive intervals ensuring global exponential stability of the synchronization process is also given. Numerical simulations are presented finally to demonstrate the effectiveness of the theoretical results.

WZ di-boson measurements with the ATLAS experiment at the LHC and performance of resistive Micromegas in view of HL-LHC applications

International Nuclear Information System (INIS)

Manjarres-Ramos, Joany

2013-01-01

During the past two years, the CERN Large Hadron Collider (LHC) has performed exceptionally. The data collected by ATLAS made possible the first Standard Model physics measurements and produced a number of important experimental results. In the first part of this document the measurement of the WZ production with the ATLAS detector is presented and the second part is devoted to the study of resistive Micromegas properties, in view of the installation in the ATLAS spectrometer forward regions for the first phase of High Luminosity LHC (HL-LHC). The measurement of the WZ production probes the electroweak sector of the Standard Model at high energies and allows for generic tests for New Physics beyond the Standard Model. Two datasets of LHC proton-proton collisions were analyzed, 4.8 fb -1 of integrated luminosity at center-of-mass energy of 7 TeV, and 13 fb -1 at 8 TeV, collected in 2011 and the first half of 2012 respectively. Fully leptonic decay events are selected with electrons, muons and missing transverse momentum in the final state. Different date-driven estimates of the background were developed in the context of this analysis. The fiducial and total cross section of WZ production are measured and limits on anomalous triple gauge boson couplings are set. The second part of the document is devoted to the upgrade of the ATLAS detector. The conditions at the High Luminosity LHC calls for detectors capable of operating in a flux of collisions and background particles approximately ten times larger compared to today's conditions. The efficiency, resolution and robustness of resistive Micromegas were studied, as part of the R and D project aimed at the construction of large-area spark-resistant muon chambers using the Micromegas technology. (author) [fr

LHC Olympics flex physicists' brains

CERN Multimedia

2006-01-01

Physicists from around the world met at CERN to strengthen their data-deciphering skills at the second LHC Olympics workshop. Physicists gather for the second LHC Olympics workshop. Coinciding with the kick-off of the winter Olympics in Turin, more than 70 physicists gathered at CERN from across the globe for the second LHC Olympics workshop on 9-10 February. Their challenge, however, involved brains rather than brawn. As the switch-on date for the LHC draws near, scientists excited by the project want to test and improve their ability to decipher the unprecedented amount of data that the world's biggest and most powerful particle accelerator is expected to generate. The LHC Olympics is a coordinated effort to do just that, minus the gold, silver and bronze of the athletics competition. 'In some ways, the LHC is not a precision instrument. It gives you the information that something is there but it's hard to untangle and interpret what it is,' said University of Michigan physicist Gordy Kane, who organiz...

Last cast for the LHC

CERN Multimedia

2005-01-01

The first major contract signed for the LHC is drawing to a close. Belgian firm Cockerill Sambre (a member of the Arcelor Group) has just completed production of 50,000 tonnes of steel sheets for the accelerator's superconducting magnet yokes, in what has proved to be an exemplary partnership with CERN. Philippe Lebrun, Head of the AT Department, Lyn Evans, LHC Project Leader, and Lucio Rossi, Head of the AT-MAS Group, in front of the last batch of steel for the LHC at Cockerill Sambre. It was a bright red-letter day at the end of May, when Belgian firm Cockerill Sambre of the Arcelor Group marked the completion of one of the largest contracts for the LHC machine by casting the last batch of steel sheets for the LHC superconducting magnet yokes in the presence of LHC Project Leader Lyn Evans, AT Department Head Philippe Lebrun, Magnets and Superconductors (AT-MAS) Group Leader Lucio Rossi and Head of the AT-MAS Group's components centre Francesco Bertinelli. The yokes constitute approximately 80% of the acc...

The LHC on the table

CERN Multimedia

2002-01-01

How many dipoles have been manufactured so far? How many have been delivered? To find out, you can now consult the LHC Progress Dashboard on the web. The dashboard tracks progress with regard to manufacture and delivery of thirty different types of LHC components. Do you want to know everything about progress on LHC construction? The LHC's engineers have recently acquired a very useful tracking tool precisely for that purpose. This is the LHC Progress Dashboard which makes it possible to track work progress in graph form. In the interests of transparency, the LHC Project Management has decided to make it accessible to the public on the web. You can now consult normalized graphs for each of the thirty different types of components that form part of machine construction, such as the cold masses of the dipole magnets, the vacuum chambers and the octupoles, etc. The graphs show: in blue: the contractual delivery curves, i.e. the delivery schedules to which the suppliers have committed themselves in their contra...

Search for top squark pair production in final states with two leptons at LHC Run 2 with the ATLAS detector

CERN Document Server

Longo, Luigi; The ATLAS collaboration

2017-01-01

Although no experimental evidence has been found during LHC Run1, Supersymmetry (SUSY) remains one of the most promising and motivated Standard Model (SM) extensions. Focusing the attention on models where the multiplicative quantum number R-parity is conserved, the latest results in searching for pair production of top squarks decaying to a bottom quark and the lightest chargino or to a top quark and the lightest supersymmetric particle (neutralino) in final states with 2 leptons are presented, using proton-proton collision data collected by the ATLAS experiment during 2015 and 2016 at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 36.1 fb\\$^{-1}\\$. Each of the decay modes is searched in the context of a simplified model, assuming a branching ratio of 100% for both signals

Image Blocking Encryption Algorithm Based on Laser Chaos Synchronization

Directory of Open Access Journals (Sweden)

Shu-Ying Wang

2016-01-01

Full Text Available In view of the digital image transmission security, based on laser chaos synchronization and Arnold cat map, a novel image encryption scheme is proposed. Based on pixel values of plain image a parameter is generated to influence the secret key. Sequences of the drive system and response system are pretreated by the same method and make image blocking encryption scheme for plain image. Finally, pixels position are scrambled by general Arnold transformation. In decryption process, the chaotic synchronization accuracy is fully considered and the relationship between the effect of synchronization and decryption is analyzed, which has characteristics of high precision, higher efficiency, simplicity, flexibility, and better controllability. The experimental results show that the encryption algorithm image has high security and good antijamming performance.

Computation for LHC experiments: a worldwide computing grid; Le calcul scientifique des experiences LHC: une grille de production mondiale

Energy Technology Data Exchange (ETDEWEB)

Fairouz, Malek [Universite Joseph-Fourier, LPSC, CNRS-IN2P3, Grenoble I, 38 (France)

2010-08-15

In normal operating conditions the LHC detectors are expected to record about 10{sup 10} collisions each year. The processing of all the consequent experimental data is a real computing challenge in terms of equipment, software and organization: it requires sustaining data flows of a few 10{sup 9} octets per second and recording capacity of a few tens of 10{sup 15} octets each year. In order to meet this challenge a computing network implying the dispatch and share of tasks, has been set. The W-LCG grid (World wide LHC computing grid) is made up of 4 tiers. Tiers 0 is the computer center in CERN, it is responsible for collecting and recording the raw data from the LHC detectors and to dispatch it to the 11 tiers 1. The tiers 1 is typically a national center, it is responsible for making a copy of the raw data and for processing it in order to recover relevant data with a physical meaning and to transfer the results to the 150 tiers 2. The tiers 2 is at the level of the Institute or laboratory, it is in charge of the final analysis of the data and of the production of the simulations. Tiers 3 are at the level of the laboratories, they provide a complementary and local resource to tiers 2 in terms of data analysis. (A.C.)

LHC magnets

International Nuclear Information System (INIS)

Anon.

1992-01-01

Preparations for the LHC proton collider to be built in CERN's LEP tunnel continue to make good progress. In particular development work for the high field superconducting magnets to guide the almost 8 TeVproton beams through the 'tight' curve of the 27-kilometre ring are proceeding well, while the magnet designs and lattice configuration are evolving in the light of ongoing experience. At the Evian LHC Experiments meeting, this progress was covered by Giorgio Brianti

Finite-time and fixed-time synchronization analysis of inertial memristive neural networks with time-varying delays.

Science.gov (United States)

Wei, Ruoyu; Cao, Jinde; Alsaedi, Ahmed

2018-02-01

This paper investigates the finite-time synchronization and fixed-time synchronization problems of inertial memristive neural networks with time-varying delays. By utilizing the Filippov discontinuous theory and Lyapunov stability theory, several sufficient conditions are derived to ensure finite-time synchronization of inertial memristive neural networks. Then, for the purpose of making the setting time independent of initial condition, we consider the fixed-time synchronization. A novel criterion guaranteeing the fixed-time synchronization of inertial memristive neural networks is derived. Finally, three examples are provided to demonstrate the effectiveness of our main results.

LHC superconducting strand

CERN Multimedia

Patrice Loiez

1999-01-01

This cross-section through a strand of superconducting matieral as used in the LHC shows the 8000 Niobium-Titanium filaments embedded like a honeycomb in copper. When cooled to 1.9 degrees above absolute zero in the LHC accelerator, these filaments will have zero resistance and so will carry a high electric current with no energy loss.

ATLAS. LHC experiments

International Nuclear Information System (INIS)

Anon.

1995-01-01

In Greek mythology, Atlas was a Titan who had to hold up the heavens with his hands as a punishment for having taken part in a revolt against the Olympians. For LHC, the ATLAS detector will also have an onerous physics burden to bear, but this is seen as a golden opportunity rather than a punishment. The major physics goal of CERN's LHC proton-proton collider is the quest for the long-awaited£higgs' mechanism which drives the spontaneous symmetry breaking of the electroweak Standard Model picture. The large ATLAS collaboration proposes a large general-purpose detector to exploit the full discovery potential of LHC's proton collisions. LHC will provide proton-proton collision luminosities at the aweinspiring level of 1034 cm2 s~1, with initial running in at 1033. The ATLAS philosophy is to handle as many signatures as possible at all luminosity levels, with the initial running providing more complex possibilities. The ATLAS concept was first presented as a Letter of Intent to the LHC Committee in November 1992. Following initial presentations at the Evian meeting (Towards the LHC Experimental Programme') in March of that year, two ideas for generalpurpose detectors, the ASCOT and EAGLE schemes, merged, with Friedrich Dydak (MPI Munich) and Peter Jenni (CERN) as ATLAS cospokesmen. Since the initial Letter of Intent presentation, the ATLAS design has been optimized and developed, guided by physics performance studies and the LHC-oriented detector R&D programme (April/May, page 3). The overall detector concept is characterized by an inner superconducting solenoid (for inner tracking) and large superconducting air-core toroids outside the calorimetry. This solution avoids constraining the calorimetry while providing a high resolution, large acceptance and robust detector. The outer magnet will extend over a length of 26 metres, with an outer diameter of almost 20 metres. The total weight of the detector is 7,000 tonnes. Fitted with its end

Distributed synchronization of networked drive-response systems: A nonlinear fixed-time protocol.

Science.gov (United States)

Zhao, Wen; Liu, Gang; Ma, Xi; He, Bing; Dong, Yunfeng

2017-11-01

The distributed synchronization of networked drive-response systems is investigated in this paper. A novel nonlinear protocol is proposed to ensure that the tracking errors converge to zeros in a fixed-time. By comparison with previous synchronization methods, the present method considers more practical conditions and the synchronization time is not dependent of arbitrary initial conditions but can be offline pre-assign according to the task assignment. Finally, the feasibility and validity of the presented protocol have been illustrated by a numerical simulation. Copyright © 2017. Published by Elsevier Ltd.

One-dimensional map lattices: Synchronization, bifurcations, and chaotic structures

DEFF Research Database (Denmark)

Belykh, Vladimir N.; Mosekilde, Erik

1996-01-01

The paper presents a qualitative analysis of coupled map lattices (CMLs) for the case of arbitrary nonlinearity of the local map and with space-shift as well as diffusion coupling. The effect of synchronization where, independently of the initial conditions, all elements of a CML acquire uniform...... dynamics is investigated and stable chaotic time behaviors, steady structures, and traveling waves are described. Finally, the bifurcations occurring under the transition from spatiotemporal chaos to chaotic synchronization and the peculiarities of CMLs with specific symmetries are discussed....

The Cryogenic Design of the Phase I Upgrade Inner Triplet Magnets for LHC

CERN Document Server

van Weelderen, R; Peterson, T

2011-01-01

The LHC is operating with beam since end 2009. However, with the present interaction region magnets it cannot reach its nominal performance and a phased approach to upgrading them to reach that nominal performance is taken. The first phase of the LHC interaction region upgrade was approved by Council in December 2007. This phase relies on the mature Nb-Ti superconducting magnet technology with the target of increasing the LHC luminosity to 2 to 3×1034 cm-2s-1, while relying on the existing infrastructure which limits the total heat removal capacity at 1.9 K to 500 W. The Phase I Upgrade LHC interaction region final focus magnets will include four superconducting quadrupoles (low-β triplets) and one superconducting dipole (D1) cooled with pressurized, static superfluid helium (HeII) at 1.9 K. The heat absorbed in pressurized HeII, which may be more than 30 W/m due to dynamic heating from the particle beam halo, will be conducted to saturated He II at about 1.9 K and removed by the low pressure vapour. This p...

Topics in the measurement of electrons with the ATLAS detector at the LHC

CERN Document Server

Thioye, Moustapha

2008-01-01

Upon completion in 2008, the Large Hadron Collider (LHC) will accelerate and collide protons with a 14~TeV center-of-mass energy at a designed luminosity of $10^{34}\\rm {cm^{-2}s^{-1}}$. The LHC will also be able to accelerate and collide heavy ions (Pb-Pb) at a nucleon-nucleon center of mass of 5.5~TeV. It will be the most powerful instrument ever built to investigate particles properties. The ATLAS (A Toroidal LHC ApparatuS) experiment is one of five experiments at the LHC. ATLAS is a general-purpose detector designed for the discovery of new particles predicted by the Standard Model (i.e Higgs boson), and of signatures of physics beyond the Standard Model (i.e supersymmetry). These discoveries require a highly efficient detection and high-resolution measurement of leptons or photons in the final state. In ATLAS, the liquid Argon (LAr) calorimeters identify and measure electrons and photons with high resolution. This dissertation reports on a study of various topics relevant to the measurement of electrons ...

LHC Supertable

CERN Document Server

Pereira, M; Lamont, M; Muller, GJ; Teixeira, D D; McCrory, ES

2011-01-01

LHC operations generate enormous amounts of data. This data is being stored in many different databases. Hence, it is difficult for operators, physicists, engineers and management to have a clear view on the overall accelerator performance. Until recently the logging database, through its desktop interface TIMBER, was the only way of retrieving information on a fill-by-fill basis. The LHC Supertable has been developed to provide a summary of key LHC performance parameters in a clear, consistent and comprehensive format. The columns in this table represent main parameters that describe the collider’s operation such as luminosity, beam intensity, emittance, etc. The data is organized in a tabular fill-by-fill manner with different levels of detail. Particular emphasis was placed on data sharing by making data available in various open formats. Typically the contents are calculated for periods of time that map to the accelerator’s states or beam modes such as Injection, Stable Beams, etc. Data retrieval and ...

LHC Report: Beams are back in the LHC

CERN Multimedia

CERN Bulletin

2011-01-01

The LHC has shaken itself awake after the winter break, and, as the snow melts on the lower slopes, the temperature in the magnets has dropped to a chilly 1.9 K once more.   Following the cool-down, the last few weeks have seen an intense few tests of the magnets, power supplies and associated protection systems. These tests, referred to as hardware commissioning, have been completed in record time. At the same time the other accelerator systems have been put through the preparatory machine checkout. In parallel, the injectors (LINAC2, Booster, PS and SPS) have also come out of the technical stop in order to prepare to deliver beam to the LHC very early in the season. Of particular note here was the remarkably seamless transition to POPS, the PS's new main power supply system. All this work culminated in the LHC taking beam again for the first time in 2011 on Saturday, 19 February. The careful preparation paid off, with circulating beams being rapidly re-established. There then followed a programme ...

Testing a Firefly-Inspired Synchronization Algorithm in a Complex Wireless Sensor Network.

Science.gov (United States)

Hao, Chuangbo; Song, Ping; Yang, Cheng; Liu, Xiongjun

2017-03-08

Data acquisition is the foundation of soft sensor and data fusion. Distributed data acquisition and its synchronization are the important technologies to ensure the accuracy of soft sensors. As a research topic in bionic science, the firefly-inspired algorithm has attracted widespread attention as a new synchronization method. Aiming at reducing the design difficulty of firefly-inspired synchronization algorithms for Wireless Sensor Networks (WSNs) with complex topologies, this paper presents a firefly-inspired synchronization algorithm based on a multiscale discrete phase model that can optimize the performance tradeoff between the network scalability and synchronization capability in a complex wireless sensor network. The synchronization process can be regarded as a Markov state transition, which ensures the stability of this algorithm. Compared with the Miroll and Steven model and Reachback Firefly Algorithm, the proposed algorithm obtains better stability and performance. Finally, its practicality has been experimentally confirmed using 30 nodes in a real multi-hop topology with low quality links.

Impulsive stabilization and impulsive synchronization of discrete-time delayed neural networks.

Science.gov (United States)

Chen, Wu-Hua; Lu, Xiaomei; Zheng, Wei Xing

2015-04-01

This paper investigates the problems of impulsive stabilization and impulsive synchronization of discrete-time delayed neural networks (DDNNs). Two types of DDNNs with stabilizing impulses are studied. By introducing the time-varying Lyapunov functional to capture the dynamical characteristics of discrete-time impulsive delayed neural networks (DIDNNs) and by using a convex combination technique, new exponential stability criteria are derived in terms of linear matrix inequalities. The stability criteria for DIDNNs are independent of the size of time delay but rely on the lengths of impulsive intervals. With the newly obtained stability results, sufficient conditions on the existence of linear-state feedback impulsive controllers are derived. Moreover, a novel impulsive synchronization scheme for two identical DDNNs is proposed. The novel impulsive synchronization scheme allows synchronizing two identical DDNNs with unknown delays. Simulation results are given to validate the effectiveness of the proposed criteria of impulsive stabilization and impulsive synchronization of DDNNs. Finally, an application of the obtained impulsive synchronization result for two identical chaotic DDNNs to a secure communication scheme is presented.

Chaos anti-synchronization of two non-identical chaotic systems with known or fully unknown parameters

International Nuclear Information System (INIS)

Al-Sawalha, Ayman

2009-01-01

This work is devoted to investigating the anti-synchronization between two novel different chaotic systems. Two different anti-synchronization methods are proposed. Active control is applied when system parameters are known and adaptive control is employed when system parameters are uncertain or unknown. Controllers and update laws of parameters are designed based on Lyapunov stability theory. In both cases, sufficient conditions for the anti-synchronization are obtained analytically. Finally, a numerical simulations is presented to show the effectiveness of the proposed chaos anti-synchronization schemes.

Electronics for LHC experiments

International Nuclear Information System (INIS)

Bourgeois, Francois

1995-01-01

Full text: A major effort is being mounted to prepare the way handling the high interaction rates expected from CERN's new LHC proton-proton collider (see, for example, November, page 6). September saw the First Workshop on Electronics for LHC Experiments, organized by Lisbon's Particle Physics Instrumentation Laboratory (LIP) on behalf of CERN's LHC Electronics Review Board (LERB - March, page 2). Its purpose was not only for the LERB to have a thorough review of ongoing activities, but also to promote cross fertilization in the engineering community involved in electronics design for LHC experiments. The Workshop gathered 187 physicists and engineers from 20 countries including USA and Japan. The meeting comprised six sessions and 82 talks, with special focus on radiation-hard microelectronic processes, electronics for tracking, calorimetry and muon detectors, optoelectronics, trigger and data acquisition systems. Each topic was introduced by an invited speaker who reviewed the requirements set by the particular detector technology at LHC. At the end of each session, panel discussions were chaired by each invited speaker. Representatives from four major integrated circuit manufacturers covered advanced radiation hard processes. Two talks highlighted the importance of obsolescence and quality systems in the long-lived and demanding environment of LHC. The Workshop identified areas and encouraged efforts for rationalization and common developments within and between the different detector groups. As a result, it will also help ensure the reliability and the long term maintainability of installed equipment. The proceedings of the Workshop are available from LIP Lisbon*. The LERB Workshop on Electronics for LHC Experiments will become a regular event, with the second taking place in Hungary, by Lake Balaton, from 23-27 September 1996. The Hungarian institutes KFKIRMKI have taken up the challenge of being as successful as LIP Lisbon in the organization

Tau reconstruction and identification with upgraded CMS detector at LHC.

CERN Document Server

AUTHOR|(CDS)2083403

2016-01-01

Tau leptons appear in the final state of many important physics processessuch as decay of the Higgs boson, supersymmetric particles and additionalheavy gauge bosons corresponding to a new symmetry. Thus tau leptonsplay very important role in LHC physics programme at all energies. Sincemajority of the tau lepton decays are hadronic, CMS employs a dedicatedprocedure to reconstruct tau leptons from the light hadrons inside jets.In view of the upcoming LHC run at 13-14 TeV, it is crucial to studythe performance of tau reconstruction and identification at high pileup and withthe upgraded CMS detector geometry. An overview of the results fromsimulations, in the context of CMS experiment, will be presented in the talkincluding the fake rates and their dependence of kinematic variables.

The LHC access system LACS and LASS

CERN Document Server

Ninin, P

2005-01-01

The LHC complex is divided into a number of zones with different levels of access controls.Inside the interlocked areas, the personnel protection is ensured by the LHC Access System.The system is made of two parts:the LHC Access Safety System and the LHC Access Control System. During machine operation,the LHC Access Safety System ensures the collective protection of the personnel against the radiation hazards arising from the operation of the accelerator by interlocking the LHC key safety elements. When the beams are off, the LHC Access Control System regulates the access to the accelerator and its many subsystems.It allows a remote, local or automatic operation of the access control equipment which verifies and identifies all users entering the controlled areas.The global architecture of the LHC Access System is now designed and is being validated to ensure that it meets the safety requirements for operation of the LHC.A pilot installation will be tested in the summer 2005 to validate the concept with the us...

The LHC Tier1 at PIC: Experience from first LHC run

International Nuclear Information System (INIS)

Flix, J.; Perez-Calero Yzquierdo, A.; Accion, E.; Acin, V.; Acosta, C.; Bernabeu, G.; Bria, A.; Casals, J.; Caubet, M.; Cruz, R.; Delfino, M.; Espinal, X.; Lanciotti, E.; Lopez, F.; Martinez, F.; Mendez, V.; Merino, G.; Pacheco, A.; Planas, E.; Porto, M. C.; Rodriguez, B.; Sedov, A.

2013-01-01

This paper summarizes the operational experience of the Tier1 computer center at Port d'Informacio Cientifica (PIC) supporting the commissioning and first run (Run1) of the Large Hadron Collider (LHC). The evolution of the experiment computing models resulting from the higher amounts of data expected after there start of the LHC are also described. (authors)

Energy Deposition in Adjacent LHC Superconducting Magnets from Beam Loss at LHC Transfer Line Collimators

CERN Document Server

Beavan, S; Kain, V

2006-01-01

Injection intensities for the LHC are over an order of magnitude above the damage threshold. The collimation system in the two transfer lines is designed to dilute the beam sufficiently to avoid damage in case of accidental beam loss or mis-steered beam. To maximise the protection for the LHC most of the collimators are located in the last 300 m upstream of the injection point where the transfer lines approach the LHC machine. To study the issue of possible quenches following beam loss at the collimators part of the collimation section in one of the lines, TI 8, together with the adjacent part of the LHC has been modeled in FLUKA. The simulated energy deposition in the LHC for worst-case accidental losses and as well as for losses expected during a normal filling is presented.

Conference: STANDARD MODEL @ LHC

CERN Multimedia

2012-01-01

HCØ institute Universitetsparken 5 DK-2100 Copenhagen Ø Denmark Room: Auditorium 2 STANDARD MODEL @ LHC Niels Bohr International Academy and Discovery Center 10-13 April 2012 This four day meeting will bring together both experimental and theoretical aspects of Standard Model phenomenology at the LHC. The very latest results from the LHC experiments will be under discussion. Topics covered will be split into the following categories:     * QCD (Hard,Soft & PDFs)     * Vector Boson production     * Higgs searches     * Top Quark Physics     * Flavour physics

submitter LHC experiments

CERN Document Server

Tanaka, Shuji

2001-01-01

Large Hadron Collider (LHC) is under construction at the CERN Laboratory in Switzerland. Four experiments (ATLAS, CMS, LHCb, ALICE) will try to study the new physics by LHC from 2006. Its goal to explore the fundamental nature of matter and the basic forces. The PDF file of the transparency is located on http://www-atlas.kek.jp/sub/documents/lepsymp-stanaka.pdf.

LHC? Of course we’ve heard of the LHC!

CERN Multimedia

2009-01-01

Well, more or less. After its first outing in Meyrin (see last Bulletin issue), our street poll hits the streets of Divonne-les-Bains and the corridors of the University of Geneva. While many have heard of the LHC, the raison d’être of this "scientific whatsit" often remains a mystery.On first questioning, the "man-in-the-street" always pleads ignorance. "Lausanne Hockey Club?" The acronym LHC is not yet imprinted on people’s minds. "Erm, Left-Handed thingamajig?" But as soon as we mention the word "CERN", the accelerator pops straight into people’s minds. Variously referred to as "the circle" or "the ring", it makes you wonder whether people would have been so aware of the LHC if it had been shaped like a square. Size is another thing people remember: "It’s the world’s biggest. Up to now…" As for its purpose, well that’s another kettle of fish. &...

Heavy-ion performance of the LHC and future colliders

Energy Technology Data Exchange (ETDEWEB)

Schaumann, Michaela

2015-04-29

In 2008 the Large Hadron Collider (LHC) and its experiments started operation at the European Centre of Nuclear Research (CERN) in Geneva with the main aim of finding or excluding the Higgs boson. Only four years later, on the 4th of July 2012, the discovery of a Higgs-like particle was proven and first published by the two main experiments ATLAS and CMS. Even though proton-proton collisions are the main operation mode of the LHC, it also acts as an heavy-ion collider. Here, the term ''heavy-ion collisions'' refers to the collision between fully stripped nuclei. While the major hardware system of the LHC is compatible with heavy-ion operation, the beam dynamics and performance limits of ion beams are quite different from those of protons. Because of the higher mass and charge of the ions, beam dynamic effects like intra-beam scattering and radiation damping are stronger. Also the electromagnetic cross-sections in the collisions are larger, leading to significantly faster intensity decay and thus shorter luminosity lifetimes. As the production cross-sections for various physics processes under study of the experiments are still small at energies reachable with the LHC and because the heavy-ion run time is limited to a few days per year, it is essential to obtain the highest possible collision rate, i.e. maximise the instantaneous luminosity, in order to obtain enough events and therefore low statistical errors. Within this thesis, the past performance of the LHC in lead-lead (Pb-Pb) collisions, at a centre-of-mass energy of 2.76 TeV per colliding nucleon pair, is analysed and potential luminosity limitations are identified. Tools are developed to predict future performance and techniques are presented to further increase the luminosity. Finally, a perspective on the future of high energy heavy-ion colliders is given.

The LHC personnel safety system

International Nuclear Information System (INIS)

Ninin, P.; Valentini, F.; Ladzinski, T.

2011-01-01

Large particle physics installations such as the CERN Large Hadron Collider require specific Personnel Safety Systems (PSS) to protect the personnel against the radiological and industrial hazards. In order to fulfill the French regulation in matter of nuclear installations, the principles of IEC 61508 and IEC 61513 standard are used as a methodology framework to evaluate the criticality of the installation, to design and to implement the PSS.The LHC PSS deals with the implementation of all physical barriers, access controls and interlock devices around the 27 km of underground tunnel, service zones and experimental caverns of the LHC. The system shall guarantee the absence of personnel in the LHC controlled areas during the machine operations and, on the other hand, ensure the automatic accelerator shutdown in case of any safety condition violation, such as an intrusion during beam circulation. The LHC PSS has been conceived as two separate and independent systems: the LHC Access Control System (LACS) and the LHC Access Safety System (LASS). The LACS, using off the shelf technologies, realizes all physical barriers and regulates all accesses to the underground areas by identifying users and checking their authorizations.The LASS has been designed according to the principles of the IEC 61508 and 61513 standards, starting from a risk analysis conducted on the LHC facility equipped with a standard access control system. It consists in a set of safety functions realized by a dedicated fail-safe and redundant hardware guaranteed to be of SIL3 class. The integration of various technologies combining electronics, sensors, video and operational procedures adopted to establish an efficient personnel safety system for the CERN LHC accelerator is presented in this paper. (authors)

Luminosity Optimization for a Higher-Energy LHC

CERN Document Server

Dominguez, O

2011-01-01

A Higher-Energy Large Hadron Collider (HE-LHC) is an option to further push the energy frontier of particle physics beyond the present LHC. A beam energy of 16.5 TeV would require 20 T dipole magnets in the existing LHC tunnel, which should be compared with 7 TeV and 8.33 T for the nominal LHC. Since the synchrotron radiation power increases with the fourth power of the energy, radiation damping becomes significant for the HE-LHC. It calls for transverse and longitudinal emittance control vis-a-vis beam-beam interaction and Landau damping. The heat load from synchrotron radiation, gas scattering, and electron cloud also increases with respect to the LHC. In this paper we discuss the proposed HE-LHC beam parameters; the time evolution of luminosity, beam-beam tune shifts, and emittances during an HE-LHC store; the expected heat load; and luminosity optimization schemes for both round and flat beams.

As an introduction: Quest for New Physics in γγ interactions at the LHC

International Nuclear Information System (INIS)

Piotrzkowski, Krzysztof

2008-01-01

A significant fraction of pp collisions at the lhc will involve (quasi-real) photon interactions occurring at energies well beyond the electroweak energy scale. Hence, the lhc can to some extent be considered as a high-energy photon-photon or photon-proton collider. This offers a unique possibility for novel and complementary research where the much smaller available effective luminosity relative to parton-parton interactions, is compensated by better known initial conditions and usually simpler final states. This is in a way a method for approaching some of the issues to be addressed by the future lepton collider. Such studies of photon interactions are possible at the LHC, thanks to the striking experimental signatures of events involving photon exchanges, in particular the presence of very forward scattered protons

Global synchronization in arrays of delayed neural networks with constant and delayed coupling

International Nuclear Information System (INIS)

Cao Jinde; Li Ping; Wang Weiwei

2006-01-01

This Letter investigates the global exponential synchronization in arrays of coupled identical delayed neural networks (DNNs) with constant and delayed coupling. By referring to Lyapunov functional method and Kronecker product technique, some sufficient conditions are derived for global synchronization of such systems. These new synchronization criteria offer some adjustable matrix parameters, which is of important significance in the design and applications of such coupled DNNs, and the results improve and extend the earlier works. Finally, an example is given to illustrate the theoretical results

Generalized projective synchronization via the state observer and its application in secure communication

International Nuclear Information System (INIS)

Wu Di; Li Juan-Juan

2010-01-01

Based on the improved state observer and the pole placement technique, by adding a constant which extends the scope of use of the original system, a new design method of generalized projective synchronization is proposed. With this method, by changing the projective synchronization scale factor, one can achieve not only complete synchronization, but also anti-synchronization, as well as arbitrary percentage of projective synchronization, so that the system may attain arbitrary synchronization in a relatively short period of time, which makes this study more meaningful. By numerical simulation, and choosing appropriate scale factor, the results of repeated experiments verify that this method is highly effective and satisfactory. Finally, based on this method and the relevant feedback concept, a novel secure communication project is designed. Numerical simulation verifies that this secure communication project is very valid, and moreover, the experimental result has been greatly improved in decryption time. (general)

Search for top squark pair production in final states with two leptons at LHC Run 2 with the ATLAS detector

CERN Document Server

Longo, Luigi; The ATLAS collaboration

2017-01-01

Although no experimental evidence has been found during LHC Run1, supersymmetry (SUSY) remains one of the most promising and motivated Standard Model extensions. Focusing the attention on its minimal formulation, the Minimal Supersymmetric Standard Model (MSSM), where the multiplicative quantum number R-parity is conserved, the latest results in searching for pair production of top squarks decaying to a bottom quark and a chargino1 or to a top quark and the lightest supersymmetric particle (neutralino) in a final state with 2 leptons are presented, using proton-proton collision data collected by the ATLAS experiment during 2015 and 2016 at the center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 36.1 fb−1. Both the decay modes are searched in the context of a simplified model where a branching ratio of 100% is assumed for both signal models.

Scenarios for the LHC Upgrade

CERN Document Server

Scandale, Walter

2008-01-01

The projected lifetime of the LHC low-beta quadrupoles, the evolution of the statistical error halving time, and the physics potential all call for an LHC luminosity upgrade by the middle of the coming decade. In the framework of the CARE-HHH network three principal scenarios have been developed for increasing the LHC peak luminosity by more than a factor of 10, to values above 1035 cm−2s−1. All scenarios imply a rebuilding of the high-luminosity interaction regions (IRs) in combination with a consistent change of beam parameters. However, their respective features, bunch structures, IR layouts, merits and challenges, and luminosity variation with β∗ differ substantially. In all scenarios luminosity leveling during a store would be advantageous for the physics experiments. An injector upgrade must complement the upgrade measures in the LHC proper in order to provide the beam intensity and brightness needed as well as to reduce the LHC turnaround time for higher integrated luminosity.

Physics at LHC and beyond

CERN Document Server

2014-01-01

The topics addressed during this Conference are as follows. ---An overview of the legacy results of the LHC experiments with 7 and 8 TeV data on Standard Model physics, Scalar sector and searches for New Physics. ---A discussion of the readiness of the CMS, ATLAS, and LHCb experiments for the forthcoming high-energy run and status of the detector upgrades ---A review of the most up-to-date theory outcome on cross-sections and uncertainties, phenomenology of the scalar sector, constraints and portals for new physics. ---The presentation of the improvements and of the expected sensibilities for the Run 2 of the LHC at 13 TeV and beyond. ---A comparison of the relative scientific merits of the future projects for hadron and e+e- colliders (HL-LHC, HE-LHC, ILC, CLIC, TLEP, VHE-LHC) towards precision measurements of the Scalar boson properties and of the Electroweak-Symmetry-Breaking parameters, and towards direct searches for New Physics.

Field quality of the LHC inner triplet quadrupoles being fabricated at Fermilab

Energy Technology Data Exchange (ETDEWEB)

Gueorgui V. Velev et al.

2003-06-02

Fermilab, as part of the US-LHC Accelerator Project, has designed and is producing superconducting low-beta quadrupole magnets for the Large Hadron Collider (LHC). These 70 mm bore, 5.5 m long magnets operate in superfluid helium at 1.9 K with a maximum operating gradient of 214 T/m. Two quadrupoles, combined with a dipole orbit corrector, form a single LQXB cryogenic assembly, the Q2 optical element of the final focus triplets in the LHC interaction regions. Field quality was measured at room temperature during fabrication of the cold masses as well as at superfluid helium temperature in two thermal cycles for the first LQXB cryogenic assembly. Integral cold measurements were made with a 7.1 m long rotating coil and with a 0.8 m long rotating coil at 8 axial positions and in a range of currents. In addition to the magnetic measurements, this paper reports on the quench performance of the cold masses and on the measurements of their internal alignment.

Measurement of exclusive two-photon processes with dilepton final states in pp collisions at the LHC

CERN Document Server

Forthomme, Laurent

The unification of the electromagnetic and weak forces is a cornerstone of the standard theory of elementary particles and fundamental interactions. At the Large Hadron Collider the processes of pair production via fusion of two exchanged photons provide a unique laboratory both for testing the standard theory and for search of new phenomena in high-energy physics. In this thesis such a two-photon exclusive pair production in pp collisions has been studied experimentally, at two centre of mass energies using the data collected with the CMS experiment during LHC's Run-1. Thanks to large, effective photon fluxes and the outstanding performance of the CMS apparatus clean two-photon signal samples could be extracted. The novel track-based exclusivity selection was instrumental for making successful measurements in an extremely demanding LHC environment. In particular, the "reference" two-photon production of lepton pairs has been measured and investigated in detail, including extended phenomenological studies. A ...

Performance of the CMS precision electromagnetic calorimeter at LHC Run II and prospects for High-Luminosity LHC

Science.gov (United States)

Zhang, Zhicai

2018-04-01

Many physics analyses using the Compact Muon Solenoid (CMS) detector at the LHC require accurate, high-resolution electron and photon energy measurements. Following the excellent performance achieved during LHC Run I at center-of-mass energies of 7 and 8 TeV, the CMS electromagnetic calorimeter (ECAL) is operating at the LHC with proton-proton collisions at 13 TeV center-of-mass energy. The instantaneous luminosity delivered by the LHC during Run II has achieved unprecedented levels. The average number of concurrent proton-proton collisions per bunch-crossing (pileup) has reached up to 40 interactions in 2016 and may increase further in 2017. These high pileup levels necessitate a retuning of the ECAL readout and trigger thresholds and reconstruction algorithms. In addition, the energy response of the detector must be precisely calibrated and monitored. We present new reconstruction algorithms and calibration strategies that were implemented to maintain the excellent performance of the CMS ECAL throughout Run II. We will show performance results from the 2015-2016 data taking periods and provide an outlook on the expected Run II performance in the years to come. Beyond the LHC, challenging running conditions for CMS are expected after the High-Luminosity upgrade of the LHC (HL-LHC) . We review the design and R&D studies for the CMS ECAL and present first test beam studies. Particular challenges at HL-LHC are the harsh radiation environment, the increasing data rates, and the extreme level of pile-up events, with up to 200 simultaneous proton-proton collisions. We present test beam results of hadron irradiated PbWO crystals up to fluences expected at the HL-LHC . We also report on the R&D for the new readout and trigger electronics, which must be upgraded due to the increased trigger and latency requirements at the HL-LHC.

New strategies of the LHC experiments to meet the computing requirements of the HL-LHC era

CERN Document Server

Adamova, Dagmar

2017-01-01

The performance of the Large Hadron Collider (LHC) during the ongoing Run 2 is above expectations both concerning the delivered luminosity and the LHC live time. This resulted in a volume of data much larger than originally anticipated. Based on the current data production levels and the structure of the LHC experiment computing models, the estimates of the data production rates and resource needs were re-evaluated for the era leading into the High Luminosity LHC (HLLHC), the Run 3 and Run 4 phases of LHC operation. It turns out that the raw data volume will grow 10 times by the HL-LHC era and the processing capacity needs will grow more than 60 times. While the growth of storage requirements might in principle be satisfied with a 20 per cent budget increase and technology advancements, there is a gap of a factor 6 to 10 between the needed and available computing resources. The threat of a lack of computing and storage resources was present already in the beginning of Run 2, but could still be mitigated, e.g....

Overview of Cell Synchronization.

Science.gov (United States)

Banfalvi, Gaspar

2017-01-01

The widespread interest in cell synchronization is maintained by the studies of control mechanism involved in cell cycle regulation. During the synchronization distinct subpopulations of cells are obtained representing different stages of the cell cycle. These subpopulations are then used to study regulatory mechanisms of the cycle at the level of macromolecular biosynthesis (DNA synthesis, gene expression, protein synthesis), protein phosphorylation, development of new drugs, etc. Although several synchronization methods have been described, it is of general interest that scientists get a compilation and an updated view of these synchronization techniques. This introductory chapter summarizes: (1) the basic concepts and principal criteria of cell cycle synchronizations, (2) the most frequently used synchronization methods, such as physical fractionation (flow cytometry, dielectrophoresis, cytofluorometric purification), chemical blockade, (3) synchronization of embryonic cells, (4) synchronization at low temperature, (5) comparison of cell synchrony techniques, (6) synchronization of unicellular organisms, and (7) the effect of synchronization on transfection.

Introduction to the HL-LHC Project

CERN Document Server

Rossi , L

2015-01-01

The Large Hadron Collider (LHC) is one of largest scientific instruments ever built. It has been exploring the new energy frontier since 2010, gathering a global user community of 7,000 scientists. To extend its discovery potential, the LHC will need a major upgrade in the 2020s to increase its luminosity (rate of collisions) by a factor of five beyond its design value and the integrated luminosity by a factor of ten. As a highly complex and optimized machine, such an upgrade of the LHC must be carefully studied and requires about ten years to implement. The novel machine configuration, called High Luminosity LHC (HL-LHC), will rely on a number of key innovative technologies, representing exceptional technological challenges, such as cutting-edge 11–12 tesla superconducting magnets, very compact superconducting cavities for beam rotation with ultra-precise phase control, new technology for beam collimation and 300-meter-long high-power superconducting links with negligible energy dissipation. HL-LHC federa...

Introduction to the theory of LHC collisions

CERN Document Server

Mangano, Michelangelo L

2015-01-01

This chapter illustrates the basic principles underlying the use of perturbative QCD in predicting the structure of hard processes in high-energy hadronic collisions. It starts with a discussion of the factorization formula, which is the basis for the description of all hard processes in terms of universal functions parametrizing the density of quarks and gluons inside the proton. It then discusses the evolution of the perturbative final states, made of quarks and gluons, toward physical systems made of hadrons. Finally, several applications and examples of comparisons between the theoretical predictions and current data are presented. These provide a picture of the success of this theoretical framework, giving good confidence in the reliability of its future applications to the study of LHC collisions.

Injection Protection Upgrade for the HL-LHC

CERN Document Server

AUTHOR|(CDS)2067108; Biancacci, Nicolo; Bracco, Chiara; Frasciello, Oscar; Gentini, Luca; Goddard, Brennan; Lechner, Anton; Maciariello, Fausto; Perillo Marcone, Antonio; Salvant, Benoit; Shetty, Nikhil Vittal; Steele, Genevieve; Velotti, Francesco; Zobov, Mikhail

2015-01-01

The injector complex of the LHC is undergoing important changes in the light of the LIU project to provide brighter beams to the LHC. For this reason and as part of the High Luminosity LHC project the injection protection system of the LHC will be upgraded in the Long Shutdown 2 (2018 - 2019) to be able to protect downstream elements against injection failures with the high brightness, high intensity HL-LHC beams. The upgraded LHC injection protection system will consist of a segmented injection protection absorber TDIS, and auxiliary collimators and masks. The layout modifications are described, and the machine element protection and absorber jaw robustness studies are presented for the new systems.

Exponential cluster synchronization in directed community networks via adaptive nonperiodically intermittent pinning control

Science.gov (United States)

Zhou, Peipei; Cai, Shuiming; Jiang, Shengqin; Liu, Zengrong

2018-02-01

In this paper, the problem of exponential cluster synchronization for a class of directed community networks is investigated via adaptive nonperiodically intermittent pinning control. By constructing a novel piecewise continuous Lyapunov function, some sufficient conditions to guarantee globally exponential cluster synchronization are derived. It is noted that the derived cluster synchronization criteria rely on the control rates, but not the control widths or the control periods, which facilitates the choice of the control periods in practical applications. A numerical example is finally presented to show the effectiveness of the obtained theoretical results.

Exponential synchronization of the Genesio-Tesi chaotic system via a novel feedback control

International Nuclear Information System (INIS)

Park, Ju H

2007-01-01

A novel feedback control scheme is proposed for exponential synchronization of the Genesio-Tesi chaotic system. The feedback controller consists of two parts: a linear dynamic control law and a nonlinear control one. For exponential synchronization between the drive and response Genesio-Tesi systems, the Lyapunov stability analysis is used. Then an existence criterion for the stabilizing controller is presented in terms of linear matrix inequalities (LMIs). The LMIs can be solved easily by various convex optimization algorithms. Finally, a numerical simulation is illustrated to show the effectiveness of the proposed chaos synchronization scheme

A way to synchronize models with seismic faults for earthquake forecasting

DEFF Research Database (Denmark)

González, Á.; Gómez, J.B.; Vázquez-Prada, M.

2006-01-01

Numerical models are starting to be used for determining the future behaviour of seismic faults and fault networks. Their final goal would be to forecast future large earthquakes. In order to use them for this task, it is necessary to synchronize each model with the current status of the actual....... Earthquakes, though, provide indirect but measurable clues of the stress and strain status in the lithosphere, which should be helpful for the synchronization of the models. The rupture area is one of the measurable parameters of earthquakes. Here we explore how it can be used to at least synchronize fault...... models between themselves and forecast synthetic earthquakes. Our purpose here is to forecast synthetic earthquakes in a simple but stochastic (random) fault model. By imposing the rupture area of the synthetic earthquakes of this model on other models, the latter become partially synchronized...

Exponentially asymptotical synchronization in uncertain complex dynamical networks with time delay

Energy Technology Data Exchange (ETDEWEB)

Luo Qun; Yang Han; Li Lixiang; Yang Yixian [Information Security Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Han Jiangxue, E-mail: luoqun@bupt.edu.c [National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

2010-12-10

Over the past decade, complex dynamical network synchronization has attracted more and more attention and important developments have been made. In this paper, we explore the scheme of globally exponentially asymptotical synchronization in complex dynamical networks with time delay. Based on Lyapunov stability theory and through defining the error function between adjacent nodes, four novel adaptive controllers are designed under four situations where the Lipschitz constants of the state function in nodes are known or unknown and the network structure is certain or uncertain, respectively. These controllers could not only globally asymptotically synchronize all nodes in networks, but also ensure that the error functions do not exceed the pre-scheduled exponential function. Finally, simulations of the synchronization among the chaotic system in the small-world and scale-free network structures are presented, which prove the effectiveness and feasibility of our controllers.

[Triple synchronous primary gynaecological tumours. A case report].

Science.gov (United States)

Gutiérrez-Palomino, Laura; Romo-de Los Reyes, José María; Pareja-Megía, María Jesús; García-Mejido, José Antonio

2016-01-01

Synchronous multiple primary malignancies in the female genital tract are infrequent. From 50 to 70% of them corresponds to synchronous cancers of the endometrium and ovary. To our knowledge, this is only the third case report in the international literature of three concurrent gynaecological cancers of epithelial origin. A case is presented, as well as a literature review due to the infrequency of its diagnosis and the lack of information on the subject. A 49-year-old woman, with previous gynaecological history of ovarian endometriosis. She underwent a hysterectomy and bilateral oophorectomy, as she had been diagnosed with endometrial hyperplasia with atypia. The final histopathology reported synchronous ovarian, Fallopian tube, and endometrial cancer. An extension study and complete surgical staging was performed, both being negative. She received adjuvant treatment of chemotherapy and radiotherapy. She is currently free of disease. The aetiology is uncertain. There is controversy relating to increased susceptibility of synchronous neoplasms to pelvic endometriosis and inherited genetic syndromes. Its diagnosis needs to differentiate them from metastatic disease. Additionally, they are problematical from a clinical, diagnostic, therapeutic, and prognostic point of view. The presentation of more cases of triple synchronous cancers is necessary for a complete adjuvant and surgical treatment. Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.

Academic Training: Monte Carlo generators for the LHC

CERN Multimedia

Françoise Benz

2005-01-01

2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 4, 5, 6, 7 April from 11.00 to 12.00 hrs - Main Auditorium, bldg. 500 Monte Carlo generators for the LHC T. SJOSTRAND / CERN-PH, Lund Univ. SE Event generators today are indispensable as tools for the modelling of complex physics processes, that jointly lead to the production of hundreds of particles per event at LHC energies. Generators are used to set detector requirements, to formulate analysis strategies, or to calculate acceptance corrections. These lectures describe the physics that goes into the construction of an event generator, such as hard processes, initial- and final-state radiation, multiple interactions and beam remnants, hadronization and decays, and how these pieces come together. The current main generators are introduced, and are used to illustrate uncertainties in the physics modelling. Some trends for the future are outlined. ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch

Multi parton interactions with CMS detector at LHC

International Nuclear Information System (INIS)

Ciangottini, D.

2014-01-01

Multi parton interactions (MPI) are experiencing a growing popularity and are widely invoked to account for observations that cannot be explained otherwise: the activity of the Underlying Event, the rates for multiple heavy flavour production, the survival probability of large rapidity gaps in hard diffraction, etc. The definition, implementation and tuning of MPI models in Monte Carlo generators plays an important role for the LHC physics: a better definition of the collision dynamics and a better definition of background processes. CMS was involved into the MPI characterization from the beginning of the LHC data-taken, starting from the Underlying Event measurements in Minimum Bias events. With the large integrated luminosity available, the Double Parton Scattering (DPS) measurements (2 hard events in the same proton-proton collision) can be performed in different final states and at different energy scales. The proposed contribution is intended to review past and ongoing studies on MPI with the CMS detector, providing a common interpretation.

LHC: seven golden suppliers

CERN Multimedia

2005-01-01

The fourth CERN Golden Hadron awards saw seven of the LHC's best suppliers receive recognition for the high quality of their work, compliance with delivery deadlines, flexibility and adaptability to the demanding working conditions of the project. The representatives of the seven companies which received awards during the Golden Hadron ceremony, standing with Lyn Evans, LHC Project Leader. 'The Golden Hadron awards are a symbol of our appreciation of not only the quality and timely delivery of components but also the collaborative and flexible way the firms have contributed to this very difficult project,' said Lyn Evans, head of the LHC project. The awards went to Kemppi-Kempower (Finland), Metso Powdermet (Finland), Transtechnik (Germany), Babcock Noell Nuclear (Germany), Iniziative Industriali (Italy), ZTS VVU Kosice (Slovakia), and Jehier (France). Babock Noell Nuclear (BNN) successfully produced one-third (416 cold dipole masses) of the LHC's superconducting dipole magnets, one of the most critical an...

A table-top LHC

CERN Multimedia

Barbara Warmbein

2011-01-01

Many years ago, when ATLAS was no more than a huge empty underground cavern and Russian artillery shell casings were being melted down to become part of the CMS calorimetry system, science photographer Peter Ginter started documenting the LHC’s progress. He was there when special convoys of equipment crossed the Jura at night, when cranes were lowering down detector slices and magnet coils were being wound in workshops. Some 18 years of LHC history have been documented by Ginter, and the result has just come out as a massive coffee table book full of double-page spreads of Ginter’s impressive images.   The new coffee table book, LHC: the Large Hadron Collider. Published by the Austrian publisher Edition Lammerhuber in cooperation with CERN and UNESCO Publishing, LHC: the Large Hadron Collider is an unusual piece in the company’s portfolio. As the publisher’s first science book, LHC: the Large Hadron Collider weighs close to five kilos and comes in a s...

Looking back over the LHC Project

CERN Multimedia

2007-01-01

Have you always wanted to delve into the history of the phenomenal LHC Project? Well, now you can. A chronological history of the LHC Project is now available on the web. It traces the Project's key milestones, from its first approval in 1994 to the most recent spectacular transport operations for detector components. The photographs used to illustrate these events are linked to the CDS database, allowing visitors who wish to do so the opportunity to download them or to search for photographs associated with subjects that are of interest to them. To explore the history of the LHC Project, go to the CERN Public Welcome page and click on 'LHC Milestones' or simply go directly to the following link: http://cern.ch/LHC-Milestones/

Multilepton signals of gauge mediated supersymmetry breaking at the LHC

Energy Technology Data Exchange (ETDEWEB)

D' Hondt, Jorgen [Theoretische Natuurkunde and IIHE/ELEM, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels (Belgium); International Solvay Institutes, Brussels (Belgium); De Causmaecker, Karen [Theoretische Natuurkunde and IIHE/ELEM, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels (Belgium); International Solvay Institutes, Brussels (Belgium); Theory Division, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Fuks, Benjamin [Theory Division, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Institut Pluridisciplinaire Hubert Curien/Département Recherches Subatomiques, Université de Strasbourg/CNRS-IN2P3, 23 Rue du Loess, F-67037 Strasbourg (France); Mariotti, Alberto [Institute for Particle Physics Phenomenology, Durham University, Durham DH1 3LE (United Kingdom); Mawatari, Kentarou [Theoretische Natuurkunde and IIHE/ELEM, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels (Belgium); International Solvay Institutes, Brussels (Belgium); Petersson, Christoffer [International Solvay Institutes, Brussels (Belgium); Physique Théorique et Mathématique, Université Libre de Bruxelles, C.P. 231, B-1050 Brussels (Belgium); Department of Fundamental Physics, Chalmers University of Technology, 412 96 Göteborg (Sweden); Redigolo, Diego [International Solvay Institutes, Brussels (Belgium); Physique Théorique et Mathématique, Université Libre de Bruxelles, C.P. 231, B-1050 Brussels (Belgium)

2014-04-04

We investigate multilepton LHC signals arising from electroweak processes involving sleptons. We consider the framework of general gauge mediated supersymmetry breaking, focusing on models where the low mass region of the superpartner spectrum consists of the three generations of charged sleptons and the nearly massless gravitino. We demonstrate how such models can provide an explanation for the anomalous four lepton events recently observed by the CMS Collaboration, while satisfying other existing experimental constraints. The best fit to the CMS data is obtained for a selectron/smuon mass of around 145 GeV and a stau mass of around 90 GeV. These models also give rise to final states with more than four leptons, offering alternative channels in which they can be probed and we estimate the corresponding production rates at the LHC.

Optical data transmission ASICs for the high-luminosity LHC (HL-LHC) experiments

International Nuclear Information System (INIS)

Li, X; Huang, G; Sun, X; Liu, G; Deng, B; Gong, D; Guo, D; Liu, C; Liu, T; Xiang, A C; Ye, J; Zhao, X; Chen, J; You, Y; He, M; Hou, S; Teng, P-K; Jin, G; Liang, H; Liang, F

2014-01-01

We present the design and test results of two optical data transmission ASICs for the High-Luminosity LHC (HL-LHC) experiments. These ASICs include a two-channel serializer (LOCs2) and a single-channel Vertical Cavity Surface Emitting Laser (VCSEL) driver (LOCld1V2). Both ASICs are fabricated in a commercial 0.25-μm Silicon-on-Sapphire (SoS) CMOS technology and operate at a data rate up to 8 Gbps per channel. The power consumption of LOCs2 and LOCld1V2 are 1.25 W and 0.27 W at 8-Gbps data rate, respectively. LOCld1V2 has been verified meeting the radiation-tolerance requirements for HL-LHC experiments

Higgs boson results on couplings to fermions, CP parameters and perspectives for high-lumi LHC (ATLAS AND CMS)

CERN Document Server

Brandstetter, Johannes

2018-01-01

This talk summarizes latest ATLAS and CMS results on Higgs boson couplings to fermions. Presented topics include decays into final states of pairs of tau leptons and pairs of bottom quarks as well as results on the ttH production mode. Results are complemented by tests of the CP invariance and searches for lepton flavor violating decays. Finally, prospects of future Higgs boson analyses within the scope of the High Luminosity LHC program are discussed. The presented results mostly use LHC 2016 data collected at a center-of-mass energy of $\\sqrt{\\mathrm{s}}=13~$TeV corresponding to an integrated luminosity of about 36~$\\mathrm{fb^{-1}}$.

Strong tW Scattering at the LHC

CERN Document Server

Dror, Jeff Asaf; Salvioni, Ennio; Serra, Javi

2016-01-01

Deviations of the top electroweak couplings from their Standard Model values imply that certain amplitudes for the scattering of third generation fermions and longitudinally polarized vector bosons or Higgses diverge quadratically with momenta. This high-energy growth is a genuine signal of models where the top quark is strongly coupled to the sector responsible for electroweak symmetry breaking. We propose to profit from the high energies accessible at the LHC to enhance the sensitivity to non-standard top-$Z$ couplings, which are currently very weakly constrained. To demonstrate the effectiveness of the approach, we perform a detailed analysis of $tW \\to tW$ scattering, which can be probed at the LHC via $pp\\to t\\bar{t}Wj$. By recasting a CMS analysis at 8 TeV, we derive the strongest direct bounds to date on the $Ztt$ couplings. We also design a dedicated search at 13 TeV that exploits the distinctive features of the $t\\bar{t}Wj$ signal. Finally, we present other scattering processes in the same class that...

Computation for LHC experiments: a worldwide computing grid

International Nuclear Information System (INIS)

Fairouz, Malek

2010-01-01

In normal operating conditions the LHC detectors are expected to record about 10 10 collisions each year. The processing of all the consequent experimental data is a real computing challenge in terms of equipment, software and organization: it requires sustaining data flows of a few 10 9 octets per second and recording capacity of a few tens of 10 15 octets each year. In order to meet this challenge a computing network implying the dispatch and share of tasks, has been set. The W-LCG grid (World wide LHC computing grid) is made up of 4 tiers. Tiers 0 is the computer center in CERN, it is responsible for collecting and recording the raw data from the LHC detectors and to dispatch it to the 11 tiers 1. The tiers 1 is typically a national center, it is responsible for making a copy of the raw data and for processing it in order to recover relevant data with a physical meaning and to transfer the results to the 150 tiers 2. The tiers 2 is at the level of the Institute or laboratory, it is in charge of the final analysis of the data and of the production of the simulations. Tiers 3 are at the level of the laboratories, they provide a complementary and local resource to tiers 2 in terms of data analysis. (A.C.)

Status of the consolidation of the LHC superconducting magnets and circuits

International Nuclear Information System (INIS)

Tock, J Ph; Atieh, S; Bodart, D; Bordry, F; Bourcey, N; Cruikshank, P; Dahlerup-Petersen, K; Dalin, J M; Garion, C; Musso, A; Ostojic, R; Perin, A; Pojer, M; Savary, F; Scheuerlein, C

2014-01-01

The first LHC long shutdown (LS1) started in February 2013. It was triggered by the need to consolidate the 13 kA splices between the superconducting magnets to allow the LHC to reach safely its design energy of 14 TeV center of mass. The final design of the consolidated splices is recalled. 1695 interconnections containing 10 170 splices have to be opened. In addition to the work on the 13 kA splices, the other interventions performed during the first long shut-down on all the superconducting circuits are described. All this work has been structured in a project, gathering about 280 persons. The opening of the interconnections started in April 2013 and consolidation works are planned to be completed by August 2014. This paper describes first the preparation phase with the building of the teams and the detailed planning of the operation. Then, it gives feedback from the worksite, namely lessons learnt and adaptations that were implemented, both from the technical and organizational points of view. Finally, perspectives for the completion of this consolidation campaign are given.

Status of the Consolidation of the LHC Superconducting Magnets and Circuits

Science.gov (United States)

Tock, J. Ph; Atieh, S.; Bodart, D.; Bordry, F.; Bourcey, N.; Cruikshank, P.; Dahlerup-Petersen, K.; Dalin, J. M.; Garion, C.; Musso, A.; Ostojic, R.; Perin, A.; Pojer, M.; Savary, F.; Scheuerlein, C.

2014-05-01

The first LHC long shutdown (LS1) started in February 2013. It was triggered by the need to consolidate the 13 kA splices between the superconducting magnets to allow the LHC to reach safely its design energy of 14 TeV center of mass. The final design of the consolidated splices is recalled. 1695 interconnections containing 10 170 splices have to be opened. In addition to the work on the 13 kA splices, the other interventions performed during the first long shut-down on all the superconducting circuits are described. All this work has been structured in a project, gathering about 280 persons. The opening of the interconnections started in April 2013 and consolidation works are planned to be completed by August 2014. This paper describes first the preparation phase with the building of the teams and the detailed planning of the operation. Then, it gives feedback from the worksite, namely lessons learnt and adaptations that were implemented, both from the technical and organizational points of view. Finally, perspectives for the completion of this consolidation campaign are given.

From the LHC to Future Colliders

DEFF Research Database (Denmark)

De Roeck, A.; Ellis, J.; Grojean, C.

2010-01-01

Discoveries at the LHC will soon set the physics agenda for future colliders. This report of a CERN Theory Institute includes the summaries of Working Groups that reviewed the physics goals and prospects of LHC running with 10 to 300/fb of integrated luminosity, of the proposed sLHC luminosity up...

Large hadron collider (LHC) project quality assurance plan

Energy Technology Data Exchange (ETDEWEB)

Gullo, Lisa; Karpenko, Victor; Robinson, Kem; Turner, William; Wong, Otis

2002-09-30

The LHC Quality Assurance Plan is a set of operating principles, requirements, and practices used to support Berkeley Lab's participation in the Large Hadron Collider Project. The LHC/QAP is intended to achieve reliable, safe, and quality performance in the LHC project activities. The LHC/QAP is also designed to fulfill the following objectives: (1) The LHC/QAP is Berkeley Lab's QA program document that describes the elements necessary to integrate quality assurance, safety management, and conduct of operations into the Berkeley Lab's portion of the LHC operations. (2) The LHC/QAP provides the framework for Berkeley Lab LHC Project administrators, managers, supervisors, and staff to plan, manage, perform, and assess their Laboratory work. (3) The LHC/QAP is the compliance document that conforms to the requirements of the Laboratory's Work Smart Standards for quality assurance (DOE O 414.1, 10 CFR 830.120), facility operations (DOE O 5480.19), and safety management (DOE P 450.4).

Large hadron collider (LHC) project quality assurance plan

International Nuclear Information System (INIS)

Gullo, Lisa; Karpenko, Victor; Robinson, Kem; Turner, William; Wong, Otis

2002-01-01

The LHC Quality Assurance Plan is a set of operating principles, requirements, and practices used to support Berkeley Lab's participation in the Large Hadron Collider Project. The LHC/QAP is intended to achieve reliable, safe, and quality performance in the LHC project activities. The LHC/QAP is also designed to fulfill the following objectives: (1) The LHC/QAP is Berkeley Lab's QA program document that describes the elements necessary to integrate quality assurance, safety management, and conduct of operations into the Berkeley Lab's portion of the LHC operations. (2) The LHC/QAP provides the framework for Berkeley Lab LHC Project administrators, managers, supervisors, and staff to plan, manage, perform, and assess their Laboratory work. (3) The LHC/QAP is the compliance document that conforms to the requirements of the Laboratory's Work Smart Standards for quality assurance (DOE O 414.1, 10 CFR 830.120), facility operations (DOE O 5480.19), and safety management (DOE P 450.4)

Parameter Identification and Synchronization of Uncertain Chaotic Systems Based on Sliding Mode Observer

Directory of Open Access Journals (Sweden)

Li-lian Huang

2013-01-01

Full Text Available The synchronization of nonlinear uncertain chaotic systems is investigated. We propose a sliding mode state observer scheme which combines the sliding mode control with observer theory and apply it into the uncertain chaotic system with unknown parameters and bounded interference. Based on Lyapunov stability theory, the constraints of synchronization and proof are given. This method not only can realize the synchronization of chaotic systems, but also identify the unknown parameters and obtain the correct parameter estimation. Otherwise, the synchronization of chaotic systems with unknown parameters and bounded external disturbances is robust by the design of the sliding surface. Finally, numerical simulations on Liu chaotic system with unknown parameters and disturbances are carried out. Simulation results show that this synchronization and parameter identification has been totally achieved and the effectiveness is verified very well.

Heavy-ion operation of HL-LHC

CERN Document Server

Jowett, J M; Versteegen, R

2015-01-01

The heavy-ion physics programme of the LHC will continue during the HL-LHC period with upgraded detectors capable of exploiting several times the design luminosity for nucleus–nucleus (Pb–Pb) collisions. For proton–nucleus (p–Pb) collisions, unforeseen in the original design of the LHC, a comparable increase beyond the 2013 luminosity should be attainable. We present performance projections and describe the operational strategies and relatively modest upgrades to the collider hardware that will be needed to achieve these very significant extensions to the physics potential of the High Luminosity LHC.

Effects of gap junction blockers on human neocortical synchronization.

Science.gov (United States)

Gigout, S; Louvel, J; Kawasaki, H; D'Antuono, M; Armand, V; Kurcewicz, I; Olivier, A; Laschet, J; Turak, B; Devaux, B; Pumain, R; Avoli, M

2006-06-01

Field potentials and intracellular recordings were obtained from human neocortical slices to study the role of gap junctions (GJ) in neuronal network synchronization. First, we examined the effects of GJ blockers (i.e., carbenoxolone, octanol, quinine, and quinidine) on the spontaneous synchronous events (duration = 0.2-1.1 s; intervals of occurrence = 3-27 s) generated by neocortical slices obtained from temporal lobe epileptic patients during application of 4-aminopyridine (4AP, 50 muM) and glutamatergic receptor antagonists. The synchronicity of these potentials (recorded at distances up to 5 mm) was decreased by GJ blockers within 20 min of application, while prolonged GJ blockers treatment at higher doses made them disappear with different time courses. Second, we found that slices from patients with focal cortical dysplasia (FCD) could generate in normal medium spontaneous synchronous discharges (duration = 0.4-8 s; intervals of occurrence = 0.5-90 s) that were (i) abolished by NMDA receptor antagonists and (ii) slowed down by carbenoxolone. Finally, octanol or carbenoxolone blocked 4AP-induced ictal-like discharges (duration = up to 35 s) in FCD slices. These data indicate that GJ play a role in synchronizing human neocortical networks and may implement epileptiform activity in FCD.

The Lhc beam commissioning

International Nuclear Information System (INIS)

Redarelli, S.; Bailey, R.

2008-01-01

The plans for the Lhc proton beam commissioning are presented. A staged commissioning approach is proposed to satisfy the request of the Lhc experiments while minimizing the machine complexity in early commissioning phases. Machine protection and collimation aspects will be tackled progressively as the performance will be pushed to higher beam intensities. The key parameters are the number of bunches, k b , the proton intensity pe bunch, N, and the β in the various interaction points. All together these parameters determine the total beam power and the complexity of the machine. We will present the proposed trade off between the evolution of these parameters and the Lhc luminosity performance.

On Synchronization Primitive Systems.

Science.gov (United States)

The report studies the question: what synchronization primitive should be used to handle inter-process communication. A formal model is presented...between these synchronization primitives. Although only four synchronization primitives are compared, the general methods can be used to compare other... synchronization primitives. Moreover, in the definitions of these synchronization primitives, conditional branches are explicitly allowed. In addition

Synchronization criteria for generalized reaction-diffusion neural networks via periodically intermittent control.

Science.gov (United States)

Gan, Qintao; Lv, Tianshi; Fu, Zhenhua

2016-04-01

In this paper, the synchronization problem for a class of generalized neural networks with time-varying delays and reaction-diffusion terms is investigated concerning Neumann boundary conditions in terms of p-norm. The proposed generalized neural networks model includes reaction-diffusion local field neural networks and reaction-diffusion static neural networks as its special cases. By establishing a new inequality, some simple and useful conditions are obtained analytically to guarantee the global exponential synchronization of the addressed neural networks under the periodically intermittent control. According to the theoretical results, the influences of diffusion coefficients, diffusion space, and control rate on synchronization are analyzed. Finally, the feasibility and effectiveness of the proposed methods are shown by simulation examples, and by choosing different diffusion coefficients, diffusion spaces, and control rates, different controlled synchronization states can be obtained.

LHC 2008 lectures
The LHC: an accelerator of science

CERN Multimedia

2008-01-01

In 2008, CERN will be switching on the greatest physics experiment ever undertaken. The Large Hadron Collider, or LHC, is a particle accelerator that will provide many answers to our questions about the Universe - What is the reason for mass? Where is the invisible matter in the Universe hiding? What is the relationship between matter and antimatter? Will we have to use a theory claiming more than four dimensions? … and what about "time" ? To understand better the raison d’être of the LHC, this gigantic, peerless scientific instrument and all the knowledge it can bring to us, members of the general public are invited to a series of lectures at the Globe of Science and Innovation. Thursday 8 May 2008 at 8.00 p.m. « Comment fonctionne l’Univers ? Ce que le LHC peut nous apprendre » Alvaro de Rujula, CERN physicist Thursday 15 May 2008 at 8.00 p.m. – « Une nouvelle vision du monde » Jean-Pierre Luminet, Director of...

HL-LHC kicker magnet (MKI)

CERN Multimedia

Brice, Maximilien

2018-01-01

HL-LHC kicker magnet (MKI): last vacuum test, preparation for transport to LHC transfer line in underground tunnel.The LHC injection kicker systems (MKIs) generate fast field pulses to inject the clockwise rotating beam at Point 2 and the anti-clockwise rotating beam at Point 8: there are eight MKI magnets installed in total. Each MKI magnet contains a high purity alumina tube: if an MKI magnet is replaced this tube requires conditioning with LHC beam: until it is properly conditioned, there can be high vacuum pressure due to the beam. This high pressure can also cause electrical breakdowns in the MKI magnets. A special coating (Cr2O3) has been applied to the inside of the alumina tube of an upgraded MKI magnet – this is expected to greatly reduce the pressure rise with beam. In addition, HL-LHC beam would result in excessive heating of the MKI magnets: the upgraded design includes modifications that will reduce heating, and move the power deposition to parts that will be easier to cool. Experience during 2...

The LHC and its successors

CERN Multimedia

Anaïs Schaeffer

2012-01-01

Not too long before the first long technical stop of the LHC, engineers and physicists are already working on the next generation of accelerators: HL-LHC and LHeC. The first would push proton-proton collisions to an unprecedented luminosity rate; the second would give a second wind to electron-proton collisions.   The ring-ring configuration of the LHeC would need this type of magnets, currently being studied for possible future use. In one year, the LHC will begin to change. During the first long shutdown, from December 2012 to late 2014, the machine will go through a first phase of major upgrades, with the objective of running at 7 TeV per beam at the beginning of 2015. With this long technical stop and the two others that will follow (in 2018 and 2022), a new project will see the light of day. Current plans include the study of something that looks more like a new machine rather than a simple upgrade: the High Luminosity LHC (HL-LHC). Much more powerful than the current machine, the HL-...

Hybrid beams in the LHC

CERN Multimedia

CERN Bulletin

2011-01-01

The first proton-ion beams were successfully circulated in the LHC a couple of weeks ago. Everything went so smoothly that the LHC teams had planned the first p-Pb collisions for Wednesday, 16 November. Unfortunately, a last-minute problem with a component of the PS required for proton acceleration prevented the LHC teams from making these new collisions. However, the way is open for a possible physics run with proton-lead collisions in 2012.   Members of the LHC team photographed when the first hybrid beams got to full energy. The proton and lead beams are visible on the leftmost screen up on the wall (click to enlarge the photo). The technical challenge of making different beams circulate in the LHC is by no means trivial. Even if the machine is the same, there are a number of differences when it is operated with beams of protons, beams of lead or beams of proton and lead. Provided that the beams are equal, irrespective of whether they consist of protons or lead nuclei, they revolve at the...

Technological challenges for the LHC

CERN Multimedia

CERN. Geneva; Rossi, Lucio; Lebrun, Philippe; Bordry, Frederick; Mess, Karl Hubert; Schmidt, Rüdiger

2003-01-01

For the LHC to provide particle physics with proton-proton collisions at the centre of mass energy of 14 TeV with a luminosity of 1034 cm-2s-1, the machine will operate with high-field dipole magnets using NbTi superconductors cooled to below the lambda point of helium. In order to reach design performance, the LHC requires both, the use of existing technologies pushed to the limits as well as the application of novel technologies. The construction follows a decade of intensive R&D and technical validation of major collider sub-systems. The first lecture will focus on the required LHC performance, and on the implications on the technologies. In the following lectures several examples for LHC technologies will be discussed: the superconducting magnets to deflect and focus the beams, the cryogenics to cool the magnets to a temperature below the lambda point of helium along most of the LHC circumference, the powering system supplying about 7000 magnets connected in 1700 electrical circuits with a total curr...

The long journey to the Higgs boson and beyond at the LHC: Emphasis on ATLAS

Science.gov (United States)

Jenni, Peter

2016-09-01

The journey in search for the Higgs boson with the ATLAS and CMS experiments at the Large Hadron Collider (LHC) at CERN started more than two decades ago. But the first discussions motivating the LHC project dream date back even further into the 1980s. This article will recall some of these early historical considerations, mention some of the LHC machine milestones and achievements, focus as an example of a technological challenge on the unique ATLAS superconducting magnet system, and then give an account of the physics results so far, leading to, and featuring particularly, the Higgs boson results, and sketching finally prospects for the future. With its emphasis on the ATLAS experiment it is complementary to the preceding article by Tejinder S. Virdee which focused on the CMS experiment.

Studies of Sub-Synchronous Oscillations in Large-Scale Wind Farm Integrated System

Science.gov (United States)

Yue, Liu; Hang, Mend

2018-01-01

With the rapid development and construction of large-scale wind farms and grid-connected operation, the series compensation wind power AC transmission is gradually becoming the main way of power usage and improvement of wind power availability and grid stability, but the integration of wind farm will change the SSO (Sub-Synchronous oscillation) damping characteristics of synchronous generator system. Regarding the above SSO problem caused by integration of large-scale wind farms, this paper focusing on doubly fed induction generator (DFIG) based wind farms, aim to summarize the SSO mechanism in large-scale wind power integrated system with series compensation, which can be classified as three types: sub-synchronous control interaction (SSCI), sub-synchronous torsional interaction (SSTI), sub-synchronous resonance (SSR). Then, SSO modelling and analysis methods are categorized and compared by its applicable areas. Furthermore, this paper summarizes the suppression measures of actual SSO projects based on different control objectives. Finally, the research prospect on this field is explored.

A brief review of measurements of electroweak bosons at the LHCb experiment in LHC Run 1

CERN Document Server

INSPIRE-00340962

2016-09-15

The LHCb experiment is one of four major experiments at the LHC. Despite being designed for the study of beauty and charm particles, it has made important contributions in other areas, such as the production and decay of $W$ and $Z$ bosons. Such measurements can be used to study and constrain parton distribution functions, as well as to test perturbative quantum chromodynamics in hard scattering processes. The angular structure of $Z$ boson decays to leptons can also be studied and used to measure the weak mixing angle. The phase space probed by LHCb is particularly sensitive to this quantity, and the LHCb measurement using the dimuon final state is currently the most precise determination of $\\sin^2\\theta^\\text{lept.}_\\text{eff.}$ at the LHC. LHCb measurements made using data collected during the first period of LHC operations (LHC Run 1) are discussed in this review. The article also considers the potential impact of related future measurements.

Cluster synchronization for directed community networks via pinning partial schemes

International Nuclear Information System (INIS)

Hu Cheng; Jiang Haijun

2012-01-01

Highlights: ► Cluster synchronization for directed community networks is proposed by pinning partial schemes. ► Each community is considered as a whole. ► Several novel pinning criteria are derived based on the information of communities. ► A numerical example with simulation is provided. - Abstract: In this paper, we focus on driving a class of directed networks to achieve cluster synchronization by pinning schemes. The desired cluster synchronization states are no longer decoupled orbits but a set of un-decoupled trajectories. Each community is considered as a whole and the synchronization criteria are derived based on the information of communities. Several pinning schemes including feedback control and adaptive strategy are proposed to select controlled communities by analyzing the information of each community such as indegrees and outdegrees. In all, this paper answers several challenging problems in pinning control of directed community networks: (1) What communities should be chosen as controlled candidates? (2) How many communities are needed to be controlled? (3) How large should the control gains be used in a given community network to achieve cluster synchronization? Finally, an example with numerical simulations is given to demonstrate the effectiveness of the theoretical results.

Start-up date announced

CERN Multimedia

7th August 2008. CERN has announced that the first attempt to circulate the beam in the LHC will be made on the 10th September. This news comes as the cool down phase of commissioning the accelerator reaches a successful conclusion.The next phase is the synchronization of the LHC with the SPS accelerator, the last link in the LHC’s injector chain. A first synchronization test is scheduled for the 9th August, for the clockwise circulating beam, with the second to follow over the coming weeks.Once stable circulating beams have been established in September they will be brought to collision, and the final step will be to commission the LHC’s acceleration system to boost the energy to 5 TeV, the target energy for 2008.“We’re finishing a marathon with a sprint”, said LHC project leader Lyn Evans. “It’s been a long haul, and we’re all eager to get the LHC research programme underway.”For more information, please see the recent press release at: http://press.web.cern.ch/press/PressReleases/Rele...

Quasi-projective synchronization of fractional-order complex-valued recurrent neural networks.

Science.gov (United States)

Yang, Shuai; Yu, Juan; Hu, Cheng; Jiang, Haijun

2018-08-01

In this paper, without separating the complex-valued neural networks into two real-valued systems, the quasi-projective synchronization of fractional-order complex-valued neural networks is investigated. First, two new fractional-order inequalities are established by using the theory of complex functions, Laplace transform and Mittag-Leffler functions, which generalize traditional inequalities with the first-order derivative in the real domain. Additionally, different from hybrid control schemes given in the previous work concerning the projective synchronization, a simple and linear control strategy is designed in this paper and several criteria are derived to ensure quasi-projective synchronization of the complex-valued neural networks with fractional-order based on the established fractional-order inequalities and the theory of complex functions. Moreover, the error bounds of quasi-projective synchronization are estimated. Especially, some conditions are also presented for the Mittag-Leffler synchronization of the addressed neural networks. Finally, some numerical examples with simulations are provided to show the effectiveness of the derived theoretical results. Copyright © 2018 Elsevier Ltd. All rights reserved.

Robust Tracking at the High Luminosity LHC

CERN Document Server

Woods, Natasha Lee; The ATLAS collaboration

2018-01-01

The High Luminosity LHC (HL-LHC) aims to increase the LHC data-set by an order of magnitude in order to increase its potential for discoveries. Starting from the middle of 2026, the HL-LHC is expected to reach the peak instantaneous luminosity of 7.5×10^34cm^-2s^-1 which corresponds to about 200 inelastic proton-proton collisions per beam crossing. To cope with the large radiation doses and high pileup, the current ATLAS Inner Detector will be replaced with a new all-silicon Inner Tracker. In this talk the expected performance of tracking and vertexing with the HL-LHC tracker is presented. Comparison is made to the performance with the Run2 detector. Ongoing developments of the track reconstruction for the HL-LHC are also discussed.

Modelling and transmission-line calculations of the final superconducting dipole and quadrupole chains of CERN's LHC collider methods and results

CERN Document Server

Dahlerup-Petersen, K

2001-01-01

Summary form only given, as follows. A long chain of superconducting magnets represents a complex load impedance for the powering and turns into a complex generator during the energy extraction. Detailed information about the circuit is needed for the calculation of a number of parameters and features, which are of vital importance for the choice of powering and extraction equipment and for the prediction of the circuit performance under normal and fault conditions. Constitution of the complex magnet chain impedance is based on a synthesized, electrical model of the basic magnetic elements. This is derived from amplitude and phase measurements of coil and ground impedances from d.c. to 50 kHz and the identification of poles and zeros of the impedance and transfer functions. An electrically compatible RLC model of each magnet type was then synthesized by means of a combination of conventional algorithms. Such models have been elaborated for the final, 15-m long LHC dipole (both apertures in series) as well as ...

Specification of Eight 2400 W @ 1.8 K Refrigeration Units for the LHC

CERN Document Server

Claudet, S; Jäger, B; Millet, F; Roussel, P; Tavian, L; Wagner, U

2000-01-01

The cooling capacity below 2 K for the superconducting magnets in the Large Hadron Collider (LHC), at CERN, will be provided by eight refrigeration units at 1.8 K, each of them coupled to a 4.5 K refrigerator. Taking into account the cryogenic architecture of the LHC and corresponding process design constraints, a reference solution based on a combination of cold centrifugal and warm volumetric compressors was established in 1997. The process and technical requirements expressed in the specification issued in 1998 and the procurement scenario based on pre-series acceptance prior to final series delivery between 2002 and 2004 are presented in this paper.

Stages of chaotic synchronization.

Science.gov (United States)

Tang, D. Y.; Dykstra, R.; Hamilton, M. W.; Heckenberg, N. R.

1998-09-01

In an experimental investigation of the response of a chaotic system to a chaotic driving force, we have observed synchronization of chaos of the response system in the forms of generalized synchronization, phase synchronization, and lag synchronization to the driving signal. In this paper we compare the features of these forms of synchronized chaos and study their relations and physical origins. We found that different forms of chaotic synchronization could be interpreted as different stages of nonlinear interaction between the coupled chaotic systems. (c) 1998 American Institute of Physics.

Synchronization approach for chaotic time-varying delay system based on Wirtinger inequality

Directory of Open Access Journals (Sweden)

Zhanshan Zhao

2017-01-01

Full Text Available A novel control approach based on Wirtinger inequality is designed for nonlinear chaos synchronization time delay system. In order to reduce the conservatism for the stability criterion, a Lyapunov–Krasovskii functional with triple-integral term is constructed. The improved Wirtinger inequality is used to reduce the conservative which is caused by Jensen inequality, and a stability criterion is proposed by reciprocally convex method. Furthermore, a state feedback controller is designed to synchronize the master-slave systems based on the proposed criteria through cone complementary linearization approach. Finally, a simulation for Lorenz chaos time delay system is given to prove the validity based on the proposed synchronization control approach.

Cluster synchronization of community network with distributed time delays via impulsive control

International Nuclear Information System (INIS)

Leng Hui; Wu Zhao-Yan

2016-01-01

Cluster synchronization is an important dynamical behavior in community networks and deserves further investigations. A community network with distributed time delays is investigated in this paper. For achieving cluster synchronization, an impulsive control scheme is introduced to design proper controllers and an adaptive strategy is adopted to make the impulsive controllers unified for different networks. Through taking advantage of the linear matrix inequality technique and constructing Lyapunov functions, some synchronization criteria with respect to the impulsive gains, instants, and system parameters without adaptive strategy are obtained and generalized to the adaptive case. Finally, numerical examples are presented to demonstrate the effectiveness of the theoretical results. (paper)

Synchronous ethernet and IEEE 1588 in telecoms next generation synchronization networks

CERN Document Server

2013-01-01

This book addresses the multiple technical aspects of the distribution of synchronization in new generation telecommunication networks, focusing in particular on synchronous Ethernet and IEEE1588 technologies. Many packet network engineers struggle with understanding the challenges that precise synchronization distribution can impose on networks. The usual “why”, “when” and particularly “how” can cause problems for many engineers. In parallel to this, some other markets have identical synchronization requirements, but with their own design requirements, generating further questions. This book attempts to respond to the different questions by providing background technical information. Invaluable information on state of-the-art packet network synchronization and timing architectures is provided, as well as an unbiased view on the synchronization technologies that have been internationally standardized over recent years, with the aim of providing the average reader (who is not skilled in the art) wi...

Future of LHC

CERN Document Server

Dova, Maria-Teresa; The ATLAS collaboration

2018-01-01

The High-Luminosity LHC aims to provide a total integrated luminosity of 3000 fb-1 from p-p collisions at  14 TeV over the course of 10 years. The upgraded ATLAS detector must be able to cope well with increased occupancies and data rates. The large data samples at the High-Luminosity LHC will enable precise measurements of the Higgs boson and other Standard Model particles, as well as searches for new phenomena BSM.

Physics programmes of the restarted LHC

International Nuclear Information System (INIS)

Tokushuku, Katsuo

2011-01-01

Experimental programs at the Large Hadron Collider (LHC) have started. On March 30th in 2010, proton beams collided at 7 TeV in the LHC, at the highest center-of-mass energy the humankind has ever produced. The machine will be operated almost continuously until the end of 2011, providing many collision data to explore new physics in the TeV region. The LHC has recovered from the unfortunate helium-leak incident in September 2009. In this article, after describing the history of the consolidation works in the LHC, physics prospects from the 2 year run are discussed. (author)

LHC crab-cavity aspects and strategy

International Nuclear Information System (INIS)

Calaga, R.; Tomas, R.; Zimmermann, F.

2010-01-01

The 3rd LHC Crab Cavity workshop (LHC-CC09) took place at CERN in October 2009. It reviewed the current status and identified a clear strategy towards a future crab-cavity implementation. Following the success of crab cavities in KEK-B and the strong potential for luminosity gain and leveling, CERN will pursue crab crossing for the LHC upgrade. We present a summary and outcome of the variousworkshop sessions which have led to the LHC crab-cavity strategy, covering topics like layout, cavity design, integration, machine protection, and a potential validation test in the SPS.

Stabilization and Synchronization of Memristive Chaotic Circuits by Impulsive Control

Directory of Open Access Journals (Sweden)

Limin Zou

2017-01-01

Full Text Available The purpose of this note is to study impulsive control and synchronization of memristor based chaotic circuits shown by Muthuswamy. We first establish a less conservative sufficient condition for the stability of memristor based chaotic circuits. After that, we discuss the effect of errors on stability. Meanwhile, we also discuss impulsive synchronization of two memristor based chaotic systems. Our results are more general and more applicable than the ones shown by Yang, Li, and Huang. Finally, several numerical examples are given to show the effectiveness of our methods.

LHC: forwards and onwards

CERN Multimedia

2008-01-01

Following the recent incident in Sector 3-4, which has brought the start-up of the LHC to a halt, the various teams are working hard to establish the cause, evaluate the situation and plan the necessary repairs. The LHC will be started up again in spring 2009 following the winter shutdown for the maintenance of all the CERN installations. The LHC teams are at work on warming up Sector 3-4 and establishing the cause of the serious incident that occurred on Friday, 19 September. Preliminary investigations suggest that the likely cause of the problem was a faulty electrical connection between two magnets. The connections probably melted, leading to a mechanical failure and a large leak of helium into the tunnel. However, the teams will not be able to carry out a full evaluation and assess the repairs needed until the sector has been warmed up again and inspected. "We are not worried about repairing the magnets as spare parts are available", said Lyn Evans, the LHC Project Leade...

LHC Report: Ion Age

CERN Multimedia

John Jowett for the LHC team

2013-01-01

The LHC starts the New Year facing a new challenge: proton-lead collisions in the last month before the shutdown in mid-February.    Commissioning this new and almost unprecedented mode of collider operation is a major challenge both for the LHC and its injector chain. Moreover, it has to be done very quickly to achieve a whole series of physics goals, requiring modifications of the LHC configuration, in a very short time. These include a switch of the beam directions halfway through the run, polarity reversals of the ALICE spectrometer magnet and Van der Meer scans.    The Linac3 team kept the lead source running throughout the end-of-year technical stop, and recovery of the accelerator complex was very quick. New proton and lead beams were soon ready, with a bunch filling pattern that ensures they will eventually match up in the LHC. The LEIR machine has even attained a new ion beam intensity record.  On Friday 11 January the first single bunches o...

The LHC in numbers

CERN Multimedia

Alizée Dauvergne

2010-01-01

What makes the LHC the biggest particle accelerator in the world? Here are some of the numbers that characterise the LHC, and their equivalents in terms that are easier for us to imagine.   Feature Number Equivalent Circumference ~ 27 km   Distance covered by beam in 10 hours ~ 10 billion km a round trip to Neptune Number of times a single proton travels around the ring each second 11 245   Speed of protons first entering the LHC 299 732 500 m/s 99.9998 % of the speed of light Speed of protons when they collide 299 789 760 m/s 99.9999991 % of the speed of light Collision temperature ~ 1016 °C ove...

Compact 400-Mhz Half-Wave Spoke Resonator Crab Cavity for the LHC Update

International Nuclear Information System (INIS)

Li, Zenghai

2010-01-01

Crab cavities are proposed for the LHC upgrade to improve the luminosity. There are two possible crab cavity installations for the LHC upgrade: the global scheme at Interaction Region (IR) 4 where the beam-beam separation is about 420-mm, and the local scheme at the IR5 where the beam-beam separation is only 194-mm. One of the design requirements as the result of a recent LHC-Crab cavity workshop is to develop a 400-MHz cavity design that can be utilized for either the global or local schemes at IR4 or IR5. Such a design would offer more flexibility for the final upgrade installation, as the final crabbing scheme is yet to be determined, and save R and D cost. The cavity size of such a design, however, is limited by the beam-beam separation at IR5 which can only accommodate a cavity with a horizontal size of about 145-mm, which is a design challenge for a 400-MHz cavity. To meet the new design requirements, we have developed a compact 400-MHz half-wave spoke resonator (HWSR) crab cavity that can fit into the tight spaces available at either IR4 or IR5. In this paper, we present the optimization of the HWSR cavity shape and the design of HOM, LOM, and SOM couplers for wakefield damping.

Impulsive Synchronization and Adaptive-Impulsive Synchronization of a Novel Financial Hyperchaotic System

Directory of Open Access Journals (Sweden)

Xiuli Chai

2013-01-01

Full Text Available The impulsive synchronization and adaptive-impulsive synchronization of a novel financial hyperchaotic system are investigated. Based on comparing principle for impulsive functional differential equations, several sufficient conditions for impulsive synchronization are derived, and the upper bounds of impulsive interval for stable synchronization are estimated. Furthermore, a nonlinear adaptive-impulsive control scheme is designed to synchronize the financial system using invariant principle of impulsive dynamical systems. Moreover, corresponding numerical simulations are presented to illustrate the effectiveness and feasibility of the proposed methods.

Beam Scraping for LHC Injection

CERN Document Server

Burkhardt, H; Fischer, C; Gras, J-J; Koschik, A; Kramer, Daniel; Pedersen, S; Redaelli, S

2007-01-01

Operation of the LHC will require injection of very high intensity beams from the SPS to the LHC. Fast scrapers have been installed and will be used in the SPS to detect and remove any existing halo before beams are extracted, to minimize the probability for quenching of superconducting magnets at injection in the LHC. We briefly review the functionality of the scraper system and report about measurements that have recently been performed in the SPS on halo scraping and re-population of tails.

Stabilization and synchronization of Genesio-Tesi system via single variable feedback controller

International Nuclear Information System (INIS)

Wang Guangming

2010-01-01

This Letter investigates the stabilization and synchronization of Genesio-Tesi systems. Firstly, modifying the previous method, we stabilize the Genesio-Tesi system. Then, we synchronize two identical Genesio chaotic system by extending the obtained stabilization results. To the best of our knowledge, the above controllers obtained in this Letter are simpler than those obtained in the existing results. Finally, numerical simulations verify the effectiveness and the validity of the above theoretical results.

The ATLAS Tile Calorimeter performance at LHC in pp collisions at 7 TeV

Directory of Open Access Journals (Sweden)

Bertolucci Federico

2012-06-01

Full Text Available The Tile Calorimeter (TileCal, the central section of the hadronic calorimeter of the ATLAS experiment, is a key detector component to detect hadrons, jets and taus and to measure the missing transverse energy. Due to the very good muon signal to noise ratio it assists the muon spectrometer in the identification and reconstruction of muons. The performance of the calorimeter has been measured and monitored using calibration data, random triggered data, cosmic muons, splash events and more importantly LHC collision events. The results presented assess the absolute energy scale calibration precision, the energy and timing uniformity and the synchronization precision. The results demonstrate a very good understanding of the performance of the Tile Calorimeter that is well within the design expectations.

The physics behind LHC

CERN Multimedia

CERN. Geneva

2006-01-01

What do physicists want to discover with experiments at the LHC? What is the Higgs boson? What are the new phenomena that could be observed at the LHC?I will try to answer these questions using language accessible also to non-experts. Organiser(s): L. Alvarez-Gaume / PH-THNote: * Tea & coffee will be served at 16:00.

Novel criteria for exponential synchronization of inner time-varying complex networks with coupling delay

International Nuclear Information System (INIS)

Zhang Qun-Jiao; Zhao Jun-Chan

2012-01-01

This paper mainly investigates the exponential synchronization of an inner time-varying complex network with coupling delay. Firstly, the synchronization of complex networks is decoupled into the stability of the corresponding dynamical systems. Based on the Lyapunov function theory, some sufficient conditions to guarantee its stability with any given convergence rate are derived, thus the synchronization of the networks is achieved. Finally, the results are illustrated by a simple time-varying network model with a coupling delay. All involved numerical simulations verify the correctness of the theoretical analysis. (general)

LHC physics results and prospects

CERN Document Server

Kono, Takanori; The ATLAS collaboration

2018-01-01

This talk presents the latest results from LHC Run-2 as of May 2018 which include Standard Model measurements, Higgs boson properties and beyond Standard Model search results. The prospects for future LHC runs are also shown.

From non-preemptive to preemptive scheduling using synchronization synthesis.

Science.gov (United States)

Černý, Pavol; Clarke, Edmund M; Henzinger, Thomas A; Radhakrishna, Arjun; Ryzhyk, Leonid; Samanta, Roopsha; Tarrach, Thorsten

2017-01-01

We present a computer-aided programming approach to concurrency. The approach allows programmers to program assuming a friendly, non-preemptive scheduler, and our synthesis procedure inserts synchronization to ensure that the final program works even with a preemptive scheduler. The correctness specification is implicit, inferred from the non-preemptive behavior. Let us consider sequences of calls that the program makes to an external interface. The specification requires that any such sequence produced under a preemptive scheduler should be included in the set of sequences produced under a non-preemptive scheduler. We guarantee that our synthesis does not introduce deadlocks and that the synchronization inserted is optimal w.r.t. a given objective function. The solution is based on a finitary abstraction, an algorithm for bounded language inclusion modulo an independence relation, and generation of a set of global constraints over synchronization placements. Each model of the global constraints set corresponds to a correctness-ensuring synchronization placement. The placement that is optimal w.r.t. the given objective function is chosen as the synchronization solution. We apply the approach to device-driver programming, where the driver threads call the software interface of the device and the API provided by the operating system. Our experiments demonstrate that our synthesis method is precise and efficient. The implicit specification helped us find one concurrency bug previously missed when model-checking using an explicit, user-provided specification. We implemented objective functions for coarse-grained and fine-grained locking and observed that different synchronization placements are produced for our experiments, favoring a minimal number of synchronization operations or maximum concurrency, respectively.

Construction progress of the cooling & ventilation in the LHC project

CERN Document Server

Body, Y; Josa, F; Monsted, A; Pirollet, B; CERN. Geneva. ST Division

2002-01-01

After the LEP dismantling Phase the Cooling and Ventilation Group has started the LHC construction work. Year 2001 through to 2004 will certainly be the most important period of activity for the CV group in the erection phase The author will report on the current works that are in progress on the different LHC Points distinguishing between the Ventilation and the Water Cooling installations. The Ventilation work completed in the new surface buildings in Points 1, 4,5,6 and 8. The work for the Cooling plants comprehend to the pumping stations, the cooling towers and the chilled water production stations in Points 1 and 5, For all of these activities, an updated report of the progress the work, the planning and of the expenses are given. Finally, a brief overview of the future activities is presented.

Time Delay and Long-Range Connection Induced Synchronization Transitions in Newman-Watts Small-World Neuronal Networks

Science.gov (United States)

Qian, Yu

2014-01-01

The synchronization transitions in Newman-Watts small-world neuronal networks (SWNNs) induced by time delay and long-range connection (LRC) probability have been investigated by synchronization parameter and space-time plots. Four distinct parameter regions, that is, asynchronous region, transition region, synchronous region, and oscillatory region have been discovered at certain LRC probability as time delay is increased. Interestingly, desynchronization is observed in oscillatory region. More importantly, we consider the spatiotemporal patterns obtained in delayed Newman-Watts SWNNs are the competition results between long-range drivings (LRDs) and neighboring interactions. In addition, for moderate time delay, the synchronization of neuronal network can be enhanced remarkably by increasing LRC probability. Furthermore, lag synchronization has been found between weak synchronization and complete synchronization as LRC probability is a little less than 1.0. Finally, the two necessary conditions, moderate time delay and large numbers of LRCs, are exposed explicitly for synchronization in delayed Newman-Watts SWNNs. PMID:24810595

LHC an unprecedented technological challenge

International Nuclear Information System (INIS)

Baruch, J.O.

2002-01-01

This article presents the future LHC (large hadron collider) in simple terms and gives some details concerning radiation detectors and supra-conducting magnets. LHC will take the place of the LEP inside the 27 km long underground tunnel near Geneva and is scheduled to operate in 2007. 8 years after its official launching the LHC project has piled up 2 year delay and has exceeded its initial budget (2 milliard euros) by 18%. Technological challenges and design difficulties are the main causes of these shifts. The first challenge has been carried out successfully, it was the complete clearing out of the LEP installation. In order to release 14 TeV in each proton-proton collision, powerful magnetic fields (8,33 Tesla) are necessary. 1248 supra-conducting 15 m-long bipolar magnets have to be built. 30% of the worldwide production of niobium-titanium wires will be used each year for 5 years in the design of these coils. The global cryogenic system will be gigantic and will use 94 tons of helium. 4 radiation detectors are being built: ATLAS (a toroidal LHC apparatus), CMS (compact muon solenoid), ALICE (a large ion collider experiment) and LHC-b (large hadron collider beauty). The 2 first will search after the Higgs boson, ALICE will be dedicated to the study of the quark-gluon plasma and LHC-b will gather data on the imbalance between matter and anti-matter. (A.C.)

Associative Memory pattern matching for L1 track trigger for the HL-LHC CMS

CERN Document Server

Fedi, Giacomo

2016-01-01

The High Luminosity LHC (HL-LHC) will deliver a luminosity of up to $5 × 10^{34}cm^{−2}s^{−1}$, with an average of about 140 overlapping proton-proton collisions per bunch crossing. These extreme pileup conditions place stringent requirements on the trigger system to be able to cope with the resulting event rates. A key component of the CMS upgrade for HL-LHC is a track trigger system, able to identify tracks with transverse momenta above 2 GeV/c already at the first-level trigger. We present here the status of the implementation of a prototype system, based on the combination of Associative Memory custom ASIC and modern Field Programmable Gate Array (FPGA) devices, with the purpose to demonstrate the concept based on state-of-the-art technologies, and to direct the efforts of the necessary R&D toward a final system.

Japanese contributions to CERN-LHC

International Nuclear Information System (INIS)

Kondo, Takahiko; Shintomi, Takakazu; Kimura, Yoshitaka

2001-01-01

The Large Hadron Collider (LHC) is now under construction at CERN, Geveva, to study frontier researches of particle physics. The LHC is the biggest superconducting accelerator using the most advanced cryogenics and applied superconductivities. The accelerator and large scale detectors for particle physics experiments are being constructed by collaboration with European countries and also by participation with non-CERN countries worldwide. In 1995, the Japanese government decided to take on a share in the LHC project with funding and technological contributions. KEK contributes to the development of low beta insertion superconducting quadrupole magnets and of components of the ATLAS detector by collaboration with university groups. Some Japanese companies have received contracts for technically key elements such as superconducting cable, cold compressor, nonmagnetic steel, polyimide film, and so on. An outline of the LHC project and Japanese contributions are described. (author)

Search for Standard Model H→τ"+τ"- decays in the lepton-hadron final state in proton-proton collisions with the ATLAS detector at the LHC

International Nuclear Information System (INIS)

Ruthmann, Nils

2014-01-01

This thesis presents a search for Standard Model (SM) Higgs boson decays to a pair of τ leptons in the lepton-hadron final state with the ATLAS detector at the Large Hadron Collider (LHC). The analysis is based on proton-proton collision data recorded during Run 1 of the LHC, corresponding to integrated luminosities of 4.5 fb"-"1 and 20.3 fb"-"1 at centre-of-mass energies of 7 TeV and 8 TeV, respectively. Background events from various SM processes contribute to the selected event sample at a high rate. Their contribution is efficiently separated from the expected Higgs boson signal by using boosted decision trees (BDT) in two analysis categories, which are enriched in events emerging from vector boson fusion and gluon fusion processes. The expected number of events from background processes is modelled using data-driven estimation techniques. The signal contribution is measured using a maximum likelihood fit of the BDT output distributions. An excess of events over the expected level of background events is found and corresponds to an observed (expected) significance of 2.3(2.4) standard deviations at a Higgs boson mass hypothesis of 125 GeV. The signal strength normalised to the Standard Model expectation is measured to be 0.98"+"0"."5_-_0_._5. A combined analysis of all τ-τ final states rejects the background-only hypothesis at a level of 4.5 standard deviations at m_H=125 GeV, while a significance of 3.5 standard deviations is expected. This provides evidence for the direct coupling of the recently discovered Higgs boson to tau leptons. The measured normalised signal strength of 1.4"+"0"."4"3_-_0_._3_7 is consistent with the predicted Yukawa coupling strength in the Standard Model.

Introduction to the HL-LHC Project

Science.gov (United States)

Rossi, L.; Brüning, O.

The Large Hadron Collider (LHC) is one of largest scientific instruments ever built. It has been exploring the new energy frontier since 2010, gathering a global user community of 7,000 scientists. To extend its discovery potential, the LHC will need a major upgrade in the 2020s to increase its luminosity (rate of collisions) by a factor of five beyond its design value and the integrated luminosity by a factor of ten. As a highly complex and optimized machine, such an upgrade of the LHC must be carefully studied and requires about ten years to implement. The novel machine configuration, called High Luminosity LHC (HL-LHC), will rely on a number of key innovative technologies, representing exceptional technological challenges, such as cutting-edge 11-12 tesla superconducting magnets, very compact superconducting cavities for beam rotation with ultra-precise phase control, new technology for beam collimation and 300-meter-long high-power superconducting links with negligible energy dissipation. HL-LHC federates efforts and R&D of a large community in Europe, in the US and in Japan, which will facilitate the implementation of the construction phase as a global project.

HL-LHC parameter space and scenarios

International Nuclear Information System (INIS)

Bruning, O.S.

2012-01-01

The HL-LHC project aims at a total integrated luminosity of approximately 3000 fb -1 over the lifetime of the HL-LHC. Assuming an exploitation period of ca. 10 years this goal implies an annual integrated luminosity of approximately 200 fb -1 to 300 fb -1 per year. This paper looks at potential beam parameters that are compatible with the HL-LHC performance goals and discusses briefly potential variation in the parameter space. It is shown that the design goal of the HL-LHC project can only be achieved with a full upgrade of the injector complex and the operation with β* values close to 0.15 m. Significant margins for leveling can be achieved for β* values close to 0.15 m. However, these margins can only be harvested during the HL-LHC operation if the required leveling techniques have been demonstrated in operation

Adaptative synchronization in multi-output fractional-order complex dynamical networks and secure communications

Science.gov (United States)

Mata-Machuca, Juan L.; Aguilar-López, Ricardo

2018-01-01

This work deals with the adaptative synchronization of complex dynamical networks with fractional-order nodes and its application in secure communications employing chaotic parameter modulation. The complex network is composed of multiple fractional-order systems with mismatch parameters and the coupling functions are given to realize the network synchronization. We introduce a fractional algebraic synchronizability condition (FASC) and a fractional algebraic identifiability condition (FAIC) which are used to know if the synchronization and parameters estimation problems can be solved. To overcome these problems, an adaptative synchronization methodology is designed; the strategy consists in proposing multiple receiver systems which tend to follow asymptotically the uncertain transmitters systems. The coupling functions and parameters of the receiver systems are adjusted continually according to a convenient sigmoid-like adaptative controller (SLAC), until the measurable output errors converge to zero, hence, synchronization between transmitter and receivers is achieved and message signals are recovered. Indeed, the stability analysis of the synchronization error is based on the fractional Lyapunov direct method. Finally, numerical results corroborate the satisfactory performance of the proposed scheme by means of the synchronization of a complex network consisting of several fractional-order unified chaotic systems.

High Luminosity LHC (HL-LHC) general infographics

CERN Multimedia

Landua, Fabienne

2016-01-01

The High-Luminosity LHC, which is expected to be operational after 2025, will increase the LHC’s luminosity by a factor of 10. To achieve this major upgrade, several technologies, some of which are completely innovative, are being developed.

Electronics at LHC

CERN Document Server

Hall, Geoffrey

1998-01-01

An overview of the electronic readout systems planned for use in the CMS and ATLAS experiments at the LHC will be given, with an emphasis on the motivations for the designs adopted and major technologies to be employed, specially those which are specific to LHC. At its design luminosity, the LHC will deliver hundreds of millions of proton-proton interactions per second. Storage and computing limitations limit the number of physics events that can be recorded to about 100 per second. The selection will be carried out by the Trigger and data acquisition systems of the experiments. This lecture will review the requirements, architectures and various designs currently considered. Introduction. Structure of gauge theories. The QED and QCD examples. Chiral theories. The electroweak theory. Spontaneous symmetry breaking. The Higgs machanism.Gauge boson and fermion masses. Yukawa coupling. Charges current couplings. The Cabibbo-Kobayashi-Maskawa matrix and CP violation. neutral current couplings. the Clashow-Iliopoul...

LHC Report: Now it’s full speed ahead (still with probe beam)

CERN Multimedia

Mike Lamont

2015-01-01

Since the last report, the commissioning with beam was delayed after a short to ground appeared in the cold mass of the main dipole chain in sector 3-4. After a remarkable team effort coordinated by the Machine Protection group, a procedure to burn away the small piece of metallic debris that was causing the earth fault was conceived, prototyped, tested and deployed. The intervention was successfully completed on the afternoon of 31 March and the first beams circulated in the LHC on Sunday, 5 April. Just a few days later, at just past midnight on Friday, 10 April, beam was ramped up to 6.5 TeV.   "LHC page 1" shows the status of the LHC last night. The black line shows the beam energy increasing to 6.5 TeV. The intervention successfully conducted in sector 3-4 opened the way for the completion of quench training in the sector and the final qualification of the circuit. This marked the end of a long and arduous powering test campaign that has fully qualified all circuits for...

Event-triggered synchronization for reaction-diffusion complex networks via random sampling

Science.gov (United States)

Dong, Tao; Wang, Aijuan; Zhu, Huiyun; Liao, Xiaofeng

2018-04-01

In this paper, the synchronization problem of the reaction-diffusion complex networks (RDCNs) with Dirichlet boundary conditions is considered, where the data is sampled randomly. An event-triggered controller based on the sampled data is proposed, which can reduce the number of controller and the communication load. Under this strategy, the synchronization problem of the diffusion complex network is equivalently converted to the stability of a of reaction-diffusion complex dynamical systems with time delay. By using the matrix inequality technique and Lyapunov method, the synchronization conditions of the RDCNs are derived, which are dependent on the diffusion term. Moreover, it is found the proposed control strategy can get rid of the Zeno behavior naturally. Finally, a numerical example is given to verify the obtained results.

Theoretical and Experimental Study on Electromechanical Coupling Properties of Multihammer Synchronous Vibration System

Directory of Open Access Journals (Sweden)

Xin Lai

2016-01-01

Full Text Available Industrial simulation of real external load using multiple exciting points or increasing exciting force by synchronizing multiple exciting forces requires multiple vibration hammers to be coordinated and work together. Multihammer vibration system which consists of several hammers is a complex electromechanical system with complex electromechanical coupling. In this paper, electromechanical coupling properties of such a multihammer vibration system were studied in detail using theoretical derivation, numerical simulation, and experiment. A kinetic model of multihammer synchronous vibration system was established, and approximate expressions for electromechanical coupling strength were solved using a small parameter periodic averaging method. Basic coupling rules and reasons were obtained. Self-synchronization and frequency hopping phenomenon were also analyzed. Subsequently, numerical simulations were carried out and electromechanical coupling process was obtained for different parameters. Simulation results verify correctness of the proposed model and results. Finally, experiments were carried out, self-synchronization and frequency hopping phenomenon were both observed, and results agree well with theoretical deduction and simulation results. These results provide theoretical foundations for multihammer synchronous vibration system and its synchronous control.

Pinning-controlled synchronization of complex networks with bounded or unbounded synchronized regions

International Nuclear Information System (INIS)

Yan-Li, Zou; Guan-Rong, Chen

2009-01-01

This paper studies pinning-controlled synchronization of complex networks with bounded or unbounded synchronized regions. To study a state-feedback pinning-controlled network with N nodes, it first converts the controlled network to an extended network of N+1 nodes without controls. It is shown that the controlled synchronizability of the given network is determined by the real part of the smallest nonzero eigenvalue of the coupling matrix of its extended network when the synchronized region is unbounded; but it is determined by the ratio of the real parts of the largest and the smallest nonzero eigenvalues of the coupling matrix when the synchronized region is bounded. Both theoretical analysis and numerical simulation show that the portion of controlled nodes has no critical values when the synchronized region is unbounded, but it has a critical value when the synchronized region is bounded. In the former case, therefore, it is possible to control the network to achieve synchronization by pinning only one node. In the latter case, the network can achieve controlled synchronization only when the portion of controlled nodes is larger than the critical value. (general)

Non-standard charged Higgs decay at the LHC in Next-to-Minimal Supersymmetric Standard Model

Energy Technology Data Exchange (ETDEWEB)

Bandyopadhyay, Priyotosh [Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento and INFN-Lecce,Via Arnesano, 73100 Lecce (Italy); Huitu, Katri [Department of Physics, and Helsinki Institute of Physics,P.O.B 64 (Gustaf Hällströmin katu 2), FI-00014 University of Helsinki (Finland); Niyogi, Saurabh [The Institute of Mathematical Sciences,CIT Campus, Chennai (India)

2016-07-04

We consider next-to-minimal supersymmetric standard model (NMSSM) which has a gauge singlet superfield. In the scale invariant superpotential we do not have the mass terms and the whole Lagrangian has an additional Z{sub 3} symmetry. This model can have light scalar and/or pseudoscalar allowed by the recent data from LHC and the old data from LEP. We investigate the situation where a relatively light charged Higgs can decay to such a singlet-like pseudoscalar and a W{sup ±} boson giving rise to a final state containing τ and/or b-jets and lepton(s). Such decays evade the recent bounds on charged Higgs from the LHC, and according to our PYTHIA-FastJet based simulation can be probed with 10 fb{sup −1} at the LHC center of mass energy of 13 and 14 TeV.

Status of the LHC machine

International Nuclear Information System (INIS)

Faugeras, P.

1997-01-01

The report represents itself a set of diagrams, characterizing: the LHC main parameters for proton-proton collisions and lead ion collisions, parameters of SC dipole and quadrupole magnets and outlines of their designs, LHC cryogenic systems, injection complex and detectors [ru

Pinning synchronization of hybrid-coupled directed delayed dynamical network via intermittent control.

Science.gov (United States)

Cai, Shuiming; Zhou, Peipei; Liu, Zengrong

2014-09-01

This paper concerns the problem of exponential synchronization for a class of general delayed dynamical networks with hybrid coupling via pinning periodically intermittent control. Both the internal delay and coupling delay are taken into account in the network model. Meanwhile, the transmission delay and self-feedback delay are involved in the delayed coupling term. By establishing a new differential inequality, several simple and useful exponential synchronization criteria are derived analytically. It is shown that the controlled synchronization state can vary in comparison with the conventional synchronized solution, and the degree of the node and the inner delayed coupling matrix play important roles in the controlled synchronization state. By choosing different inner delayed coupling matrices and the degrees of the node, different controlled synchronization states can be obtained. Furthermore, the detail pinning schemes deciding what nodes should be chosen as pinned candidates and how many nodes are needed to be pinned for a fixed coupling strength are provided. The simple procedures illuminating how to design suitable intermittent controllers in real application are also given. Numerical simulations, including an undirected scale-free network and a directed small-world network, are finally presented to demonstrate the effectiveness of the theoretical results.

HL-LHC (High-Luminosity LHC) first stone ceremony June 2018

CERN Document Server

Brice, Maximilien

2018-01-01

The first two pictures: Point 1 of the LHC. The Director-General of CERN inserts the time capsule containing a document submitted by France submits a document which is inserted in a time capsule at Point 1 of the LHC. This is the article "Geneva" of the Encyclopedia de Diderot and d'Alembert. In August 1756, during his stay in Geneva, Voltaire stayed in a property called Les Délices, many visitors including d'Alembert were involved in writing this article. Today, that location is the Library of Geneva's centre of research for the Enlightenment period. The following two pictures: Point 5 of the LHC. The Director-General of CERN inserts the time capsule containing a document submitted by the Republic and Canton of Geneva. This historic document from 1952 is the telegram by which the President of the Council of State at the time, Mr. Louis Casai, announced to his fellow members of the Government of Geneva the news of the decision taken by the signatory states of the convention for the establishment of a Europea...

Loopholes in Z ' searches at the LHC: exploring supersymmetric and leptophobic scenarios

Science.gov (United States)

Araz, Jack Y.; Corcella, Gennaro; Frank, Mariana; Fuks, Benjamin

2018-02-01

Searching for heavy vector bosons Z ', predicted in models inspired by Grand Unification Theories, is among the challenging objectives of the LHC. The ATLAS and CMS collaborations have looked for Z ' bosons assuming that they can decay only into Standard Model channels, and have set exclusion limits by investigating dilepton, dijet and, to a smaller extent, top-antitop final states. In this work we explore possible loopholes in these Z ' searches, by studying supersymmetric as well as leptophobic scenarios. We demonstrate the existence of realizations in which the Z ' boson automatically evades the typical bounds derived from the analyses of the Drell-Yan invariant-mass spectrum. Dileptonic final states can in contrast only originate from supersymmetric Z ' decays and are thus accompanied by additional effects. This feature is analyzed in the context of judiciously chosen bench-mark configurations, for which visible signals could be expected in future LHC data with a 4 σ - 7 σ significance. Our results should hence motivate an extension of the current Z ' search program to account for supersymmetric and leptophobic models.

Commissioning of the LHC

CERN Multimedia

CERN. Geneva

2007-01-01

The LHC construction is now approaching the end and it is now time to prepare for commissioning with beam. The behavior of a proton storage ring is much different to that of LEP, which profited from strong radiation damping to keep the beam stable. Our last experience with a hadron collider at CERN goes back more than 15 years when the proton-antiproton collider last operated. Ppbar taught us a lot about the machine physics of bunched beam proton storage rings and was essential input for the design of the LHC. After a short presentation of where we stand today with machine installation and hardware commissioning, I will discuss the main machine physics issues that will have to be dealt with in the LHC.

Streamlining CASTOR to manage the LHC data torrent

International Nuclear Information System (INIS)

Presti, G Lo; Curull, X Espinal; Cano, E; Fiorini, B; Ieri, A; Murray, S; Ponce, S; Sindrilaru, E

2014-01-01

This contribution describes the evolution of the main CERN storage system, CASTOR, as it manages the bulk data stream of the LHC and other CERN experiments, achieving over 90 PB of stored data by the end of LHC Run 1. This evolution was marked by the introduction of policies to optimize the tape sub-system throughput, going towards a cold storage system where data placement is managed by the experiments' production managers. More efficient tape migrations and recalls have been implemented and deployed where bulk meta-data operations greatly reduce the overhead due to small files. A repack facility is now integrated in the system and it has been enhanced in order to automate the repacking of several tens of petabytes, required in 2014 in order to prepare for the next LHC run. Finally the scheduling system has been evolved to integrate the internal monitoring. To efficiently manage the service a solid monitoring infrastructure is required, able to analyze the logs produced by the different components (about 1 kHz of log messages). A new system has been developed and deployed, which uses a transport messaging layer provided by the CERN-IT Agile Infrastructure and exploits technologies including Hadoop and HBase. This enables efficient data mining by making use of MapReduce techniques, and real-time data aggregation and visualization. The outlook for the future is also presented. Directions and possible evolution will be discussed in view of the restart of data taking activities.

Conductor Specification and Validation for High-Luminosity LHC Quadrupole Magnets

International Nuclear Information System (INIS)

Cooley, L. D.; Ghosh, A. K.; Dietderich, D. R.; Pong, I.

2017-01-01

The High Luminosity Upgrade of the Large Hadron Collider (HL-LHC) at CERN will replace the main ring inner triplet quadrupoles, identified by the acronym MQXF, adjacent to the main ring intersection regions. For the past decade, the U.S. LHC Accelerator R&D Program, LARP, has been evaluating conductors for the MQXFA prototypes, which are the outer magnets of the triplet. Recently, the requirements for MQXF magnets and cables have been published in P. Ferracin et al., IEEE Trans. Appl. Supercond., vol. 26, no. 4, 2016, Art. no.4000207, along with the final specification for Ti-alloyed Nb3Sn conductor determined jointly by CERN and LARP. This paper describes the rationale beneath the 0.85 mm diameter strand’s chief parameters, which are 108 or more sub-elements, a copper fraction not less than 52.4%, strand critical current at 4.22 K not less than 631 A at 12 T and 331 A at 15 T, and residual resistance ratio of not less than 150. This paper also compares the performance for ~100 km production lots of the five most recent LARP conductors to the first 163 km of strand made according to the HL-LHC specification. Two factors emerge as significant for optimizing performance and minimizing risk: a modest increase of the sub-element diameter from 50 to 55 μm, and a Nb:Sn molar ratio of 3.6 instead of 3.4. Furthermore, the statistics acquired so far give confidence that the present conductor can balance competing demands in production for the HL-LHC project.

Logistics of LHC cryodipoles from simulation to storage management

CERN Document Server

Foraz, K; CERN. Geneva; CERN. Geneva. TS Department

2004-01-01

The main families of LHC superconducting cryomagnets consist of approximately 1240 cryodipoles and 480 Short Straight Sections (SSS). The different contracts, which are constraining the production and installation of these cryomagnets, have been initially rated according to the baseline schedule, based on a "just in time" scheme. However the complexity of the construction and the time required to fully test the cryomagnets require that each contract is decoupled as much as possible from the others' evolutions and impose temporary storage between different assembly and test activities. Therefore, a tool simulating the logistics over the whole duration of the project was created in order to determine the number of cryomagnets to be stored at the various stages of their production. In this paper the organization of cryomagnet flow and the main challenges of logistics are analyzed on the basis of the planning of each main step before installation in the LHC. Finally, the solutions implemented for storage, handlin...

Synchronous Design and Test of Distributed Passive Radar Systems Based on Digital Broadcasting and Television

Directory of Open Access Journals (Sweden)

Wan Xianrong

2017-02-01

Full Text Available Digital broadcasting and television are important classes of illuminators of opportunity for passive radars. Distributed and multistatic structure are the development trends for passive radars. Most modern digital broadcasting and television systems work on a network, which not only provides a natural condition to distributed passive radar but also puts forward higher requirements on the design of passive radar systems. Among those requirements, precise synchronization among the receivers and transmitters as well as among multiple receiving stations, which mainly involves frequency and time synchronization, is the first to be solved. To satisfy the synchronization requirements of distributed passive radars, a synchronization scheme based on GPS is presented in this paper. Moreover, an effective scheme based on the China Mobile Multimedia Broadcasting signal is proposed to test the system synchronization performance. Finally, the reliability of the synchronization design is verified via the distributed multistatic passive radar experiments.

Early LHC physics studies What can be obtained before discoveries?

CERN Document Server

AUTHOR|(CDS)2068230

2006-01-01

The Large Hadron Collider will provide an unprecedented quantity of collision data right from the start-up. The challenge for the LHC experiments is the quick use of these data for the final commissioning of the detectors, including calibration, alignment, measuring of detector and trigger efficiencies. A new energy frontier will open up, and measurement of basic Standard Model processes will build a solid basement for any discovery studies.

LHC Highlights, from dream to reality

CERN Multimedia

CERN Bulletin

2010-01-01

The idea of the Large Hadron Collider (LHC) was born in the early 1980s. Although LEP (CERN’s previous large accelerator) was still under construction at that time, scientists were already starting to think about re-using the 27-kilometre ring for an even more powerful machine. Turning this ambitious scientific plan into reality proved to be an immensely complex task. Civil engineering work, state-of-the-art technologies, a new approach to data storage and analysis: many people worked hard for many years to accomplish all this.   Here are some of the highlights: 1984. A symposium organized in Lausanne, Switzerland, is the official starting point for the LHC. LHC prototype of the two beam pipes (1992). 1989. The first embryonic collaborations begin. 1992. A meeting in Evian, France, marks the beginning of the LHC experiments. 1994. The CERN Council approves the construction of the LHC accelerator. 1995. Japan becomes an Observer of CERN and announces a financial contribution to ...

Performance of the LHC Pre-Injectors

CERN Document Server

Benedikt, Michael; Chanel, M; Garoby, R; Giovannozzi, Massimo; Hancock, S; Martini, M; Métral, Elias; Métral, G; Schindl, Karlheinz; Vallet, J L

2001-01-01

The LHC pre-injector complex, comprising Linac 2, the PS Booster (PSB) and the PS, has undergone a major upgrade in order to meet the very stringent requirements of the LHC. Whereas bunches with the nominal spacing and transverse beam brightness were already available from the PS in 1999 [1], their length proved to be outside tolerance due to a debunching procedure plagued by microwave instabilities. An alternative scenario was then proposed, based on a series of bunch-splitting steps in the PS. The entire process has recently been implemented successfully, and beams whose longitudinal characteristics are safely inside LHC specifications are now routinely available. Variants of the method also enable bunch trains with gaps of different lengths to be generated. These are of interest for the study and possible cure of electron cloud effects in both the SPS and LHC. The paper summarizes the beam dynamics issues that had to be addressed to produce beams with all the requisite qualities for the LHC.

Control of the MKQA tuning and aperture kickers of the LHC

CERN Document Server

Barlow, R A; Pianfetti, J P; Senaj, V; Cattin, M; CERN. Geneva. TE Department

2009-01-01

The large hadron collider (LHC) at CERN has been equipped with four fast pulsed kicker magnets in RA43 situated at point 4 which are part of the measurement system for the tune and the dynamic aperture of the LHC beam (Beam 1 and Beam 2). For the tune measurement 'Q', the magnets will excite oscillations in part of the beam. This is achieved by means of a generator producing a 5 µs base half-sine pulse of 1.2 kA [1] amplitude, superimposed with a 3rd harmonic to produce a 2 µs flat top. A kick repetition rate of 2 Hz will be possible. To measure the dynamic aperture 'A' of the LHC at different beam energies, the same magnets will also be driven by a more powerful generator which produces a 43 µs base half-sine current pulse of 3.8 kA. For the 'A' mode a thyristor is used as switching element inside the generator. A final third mode named 'AC dipole' will rely on the beam being excited coherently at a frequency close but outside its Eigen-frequencies by an oscillating dipole field. The beam is expected to o...

Search for Supersymmetry with the Vector Boson Fusion tagging in pp collisions using CMS detector at the LHC

CERN Document Server

Kumari, Priyanka

2017-01-01

A search for Supersymmetry with Vector Boson Fusion (VBF) topology is performed using proton-proton collision data at 8 TeV collected with CMS detector at the LHC. The VBF processes offer a promising avenue at the LHC to study the non-colored sectors of supersymmetric extensions of the Standard Model where other searches have limited sensitivity. Final states consisting of at least two leptons, large missing transverse momentum, and two jets with a large pseudorapidity are expected in pair-production of charginos and neutralinos. The observed dijet invariant mass spectrum after the final selections is found to be consistent with the expected standard model predictions, hence the upper limits are set for the production of charginos and neutralinos with two associated jets, assuming the supersymmetric partner of the tau lepton to be the lightest slepton and the lightest slepton to be lighter than the charginos.The Run2 of LHC machine has allowed us to naturally extend this search to 13 TeV data where we utilize...

To the LHC and beyond

CERN Document Server

Rodgers, Peter

2004-01-01

CERN was conceived in 1949 as a new European laboratory to halt the exodus of physics talent from Europe to North America. In 1954, the new lab formally came into existence upon ratification of the resolution by the first 12 European member states. To further strengthen its position as the top particle-physics laboratory in the world, the CERN council agreed a new seven-point strategy. Completing the Large Hadron Collider (LHC) on schedule in 2007 is the top priority, followed by consolidating the lab's infrastructure to guarantee reliable operation of the LHC; examining the lab's experimental program apart from the LHC; coordinating research in Europe; building a new injector for the LHC in 2006; increasing R&D on the Compact Linear Collider (CLIC); and working on a long-term strategy for the lab. CERN expects to complete half of these at the end of 2008. (Edited abstract).

Review of LHC dark matter searches

International Nuclear Information System (INIS)

Kahlhoefer, Felix

2017-02-01

This review discusses both experimental and theoretical aspects of searches for dark matter at the LHC. An overview of the various experimental search channels is given, followed by a summary of the different theoretical approaches for predicting dark matter signals. A special emphasis is placed on the interplay between LHC dark matter searches and other kinds of dark matter experiments, as well as among different types of LHC searches.

Review of LHC dark matter searches

Energy Technology Data Exchange (ETDEWEB)

Kahlhoefer, Felix

2017-02-15

This review discusses both experimental and theoretical aspects of searches for dark matter at the LHC. An overview of the various experimental search channels is given, followed by a summary of the different theoretical approaches for predicting dark matter signals. A special emphasis is placed on the interplay between LHC dark matter searches and other kinds of dark matter experiments, as well as among different types of LHC searches.

Delivering LHC software to HPC compute elements

CERN Document Server

Blomer, Jakob; Hardi, Nikola; Popescu, Radu

2017-01-01

In recent years, there was a growing interest in improving the utilization of supercomputers by running applications of experiments at the Large Hadron Collider (LHC) at CERN when idle cores cannot be assigned to traditional HPC jobs. At the same time, the upcoming LHC machine and detector upgrades will produce some 60 times higher data rates and challenge LHC experiments to use so far untapped compute resources. LHC experiment applications are tailored to run on high-throughput computing resources and they have a different anatomy than HPC applications. LHC applications comprise a core framework that allows hundreds of researchers to plug in their specific algorithms. The software stacks easily accumulate to many gigabytes for a single release. New releases are often produced on a daily basis. To facilitate the distribution of these software stacks to world-wide distributed computing resources, LHC experiments use a purpose-built, global, POSIX file system, the CernVM File System. CernVM-FS pre-processes dat...

New U.S. LHC Web site launched

CERN Multimedia

Katie Yurkewicz

2007-01-01

On September 12, the U.S. Department of Energy's Office of Science launched a new Web site, www.uslhc.us, to tell the story of the U.S. role in the LHC. The site provides general information for the public about the LHC and its six experiments, as well as detailed information about the participation of physicists, engineers and students from the United States. The U.S. site joins the UK's LHC site in providing information for a national audience, with sites from several more countries expected to launch within the next year. The US LHC site features news and information about the LHC, along with high-resolution images and resources for students and educators. The site also features blogs by four particle physicists, including ATLAS collaborators Monica Dunford from the University of Chicago and Peter Steinberg from Brookhaven National Laboratory. More than 1,300 scientists from over 90 U.S. institutions participate in the LHC and its experiments, representing universities and national laboratories from...

Introduction to focus issue: Synchronization in large networks and continuous media—data, models, and supermodels

Science.gov (United States)

Duane, Gregory S.; Grabow, Carsten; Selten, Frank; Ghil, Michael

2017-12-01

The synchronization of loosely coupled chaotic systems has increasingly found applications to large networks of differential equations and to models of continuous media. These applications are at the core of the present Focus Issue. Synchronization between a system and its model, based on limited observations, gives a new perspective on data assimilation. Synchronization among different models of the same system defines a supermodel that can achieve partial consensus among models that otherwise disagree in several respects. Finally, novel methods of time series analysis permit a better description of synchronization in a system that is only observed partially and for a relatively short time. This Focus Issue discusses synchronization in extended systems or in components thereof, with particular attention to data assimilation, supermodeling, and their applications to various areas, from climate modeling to macroeconomics.

Introduction to focus issue: Synchronization in large networks and continuous media-data, models, and supermodels.

Science.gov (United States)

Duane, Gregory S; Grabow, Carsten; Selten, Frank; Ghil, Michael

2017-12-01

The synchronization of loosely coupled chaotic systems has increasingly found applications to large networks of differential equations and to models of continuous media. These applications are at the core of the present Focus Issue. Synchronization between a system and its model, based on limited observations, gives a new perspective on data assimilation. Synchronization among different models of the same system defines a supermodel that can achieve partial consensus among models that otherwise disagree in several respects. Finally, novel methods of time series analysis permit a better description of synchronization in a system that is only observed partially and for a relatively short time. This Focus Issue discusses synchronization in extended systems or in components thereof, with particular attention to data assimilation, supermodeling, and their applications to various areas, from climate modeling to macroeconomics.

Beam-gas Background Observations at LHC

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00214737; The ATLAS collaboration; Alici, Andrea; Lazic, Dragoslav-Laza; Alemany Fernandez, Reyes; Alessio, Federico; Bregliozzi, Giuseppe; Burkhardt, Helmut; Corti, Gloria; Guthoff, Moritz; Manousos, Athanasios; Sjoebaek, Kyrre; D'Auria, Saverio

2017-01-01

Observations of beam-induced background at LHC during 2015 and 2016 are presented in this paper. The four LHC experiments use the non-colliding bunches present in the physics-filling pattern of the accelerator to trigger on beam-gas interactions. During luminosity production the LHC experiments record the beam-gas interactions using dedicated background monitors. These data are sent to the LHC control system and are used to monitor the background levels at the experiments during accelerator operation. This is a very important measurement, since poor beam-induced background conditions can seriously affect the performance of the detectors. A summary of the evolution of the background levels during 2015 and 2016 is given in these proceedings.

Synchronization on effective networks

International Nuclear Information System (INIS)

Zhou Tao; Zhao Ming; Zhou Changsong

2010-01-01

The study of network synchronization has attracted increasing attentionrecently. In this paper, we strictly define a class of networks, namely effective networks, which are synchronizable and orientable networks. We can prove that all the effective networks with the same size have the same spectra, and are of the best synchronizability according to the master stability analysis. However, it is found that the synchronization time for different effective networks can be quite different. Further analysis shows that the key ingredient affecting the synchronization time is the maximal depth of an effective network: the larger depth results in a longer synchronization time. The secondary factor is the number of links. The increasing number of links connecting nodes in the same layer (horizontal links) will lead to longer synchronization time, whereas the increasing number of links connecting nodes in neighboring layers (vertical links) will accelerate the synchronization. Our analysis of the relationship between the structure and synchronization properties of the original and effective networks shows that the purely directed effective network can provide an approximation of the original weighted network with normalized input strength. Our findings provide insights into the roles of depth, horizontal and vertical links in the synchronizing process, and suggest that the spectral analysis is helpful yet insufficient for the comprehensive understanding of network synchronization.

Synchronization on effective networks

Energy Technology Data Exchange (ETDEWEB)

Zhou Tao [Web Sciences Center, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zhao Ming [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Zhou Changsong, E-mail: cszhou@hkbu.edu.h [Department of Physics, Hong Kong Baptist University, Kowloon Tong (Hong Kong)

2010-04-15

The study of network synchronization has attracted increasing attentionrecently. In this paper, we strictly define a class of networks, namely effective networks, which are synchronizable and orientable networks. We can prove that all the effective networks with the same size have the same spectra, and are of the best synchronizability according to the master stability analysis. However, it is found that the synchronization time for different effective networks can be quite different. Further analysis shows that the key ingredient affecting the synchronization time is the maximal depth of an effective network: the larger depth results in a longer synchronization time. The secondary factor is the number of links. The increasing number of links connecting nodes in the same layer (horizontal links) will lead to longer synchronization time, whereas the increasing number of links connecting nodes in neighboring layers (vertical links) will accelerate the synchronization. Our analysis of the relationship between the structure and synchronization properties of the original and effective networks shows that the purely directed effective network can provide an approximation of the original weighted network with normalized input strength. Our findings provide insights into the roles of depth, horizontal and vertical links in the synchronizing process, and suggest that the spectral analysis is helpful yet insufficient for the comprehensive understanding of network synchronization.

Digging in one last time for the LHC

CERN Multimedia

2003-01-01

A landmark event occurred during the second week of March, when the final cubic metres of earth were cleared away, completing the excavation phase for the entire LHC project . The event took place at Point 5, where the CMS detector will be installed, as civil engineering teams finished digging the cavern that connects the LHC tunnel with the bypass tunnel around the experimental cavern. Two new access shafts, two large caverns, two ancillary caverns, as well as the connecting tunnels have been excavated by the civil engineering teams. "The engineers heaved a huge sigh of relief when the work was done, because the excavations were quite risky. Anything can happen, and the risk of delays was far from zero," explains Jean Luc Baldy Head of ST Division's civil engineering group. This was especially true around Point 5, where unusual geology created some problems. The moraine-molasse interface lies 50 metres beneath the surface, or just about 18 metres above the roof of the caverns. Because the moraine consists of...

The Underlying Event and the Total Cross Section from Tevatron to the LHC

CERN Document Server

Bähr, Manuel; Seymour, Michael H

2009-01-01

Multiple partonic interactions are widely used to simulate the hadronic final state in high energy hadronic collisions, and successfully describe many features of the data. It is important to make maximum use of the available physical constraints on such models, particularly given the large extrapolation from current high energy data to LHC energies. In eikonal models, the rate of multiparton interactions is coupled to the energy dependence of the total cross section. Using a Monte Carlo implementation of such a model, we study the connection between the total cross section, the jet cross section, and the underlying event. By imposing internal consistency on the model, we derive constraints on its parameters at the LHC.

Budker INP in the LHC Machine (2)

CERN Multimedia

2001-01-01

The main BINP contributions to the LHC machine are magnets for transfer lines (26 MCHF) and bus- bar sets (23 MCHF). Budker INP is also responsible for construction of some other LHC magnets and vacuum parts. In total, the contribution to the LHC machine will reach about 90 MCHF.

CERN LHC dipole prototype success

International Nuclear Information System (INIS)

Anon.

1994-01-01

In a crash programme, the first prototype superconducting dipole magnet for CERN's LHC protonproton collider was successfully powered for the first time at CERN on 14 April, eventually sailing to 9T, above the 8.65T nominal LHC field, before quenching for the third time. The next stage is to install the delicate measuring system for making comprehensive magnetic field maps in the 10 m long, 50 mm diameter twin-apertures of the magnet. These measurements will check that the required LHC field quality has been achieved at both the nominal and injection fields

Le LHC, un tunnel cosmique

CERN Multimedia

CERN. Geneva

2009-01-01

Et si la lumière au bout du tunnel du LHC était cosmique ? En d’autres termes, qu’est-ce que le LHC peut nous apporter dans la connaissance de l’Univers ? Car la montée en énergie des accélérateurs de particules nous permet de mieux appréhender l’univers primordial, chaud et dense. Mais dans quel sens dit-on que le LHC reproduit des conditions proches du Big bang ? Quelles informations nous apporte-t-il sur le contenu de l’Univers ? La matière noire est-elle détectable au LHC ? L’énergie noire ? Pourquoi l’antimatière accumulée au CERN est-elle si rare dans l’Univers ? Et si le CERN a bâti sa réputation sur l’exploration des forces faibles et fortes qui opèrent au sein des atomes et de leurs noyaux, est-ce que le LHC peut nous apporter des informations sur la force gravitationnelle qui gouverne l’évolution cosmique ? Depuis une trentaine d’années, notre compréhension de l’univers dans ses plus grandes dimensions et l’appréhension de son comportement aux plus peti...

$A^t_{FB}$ Meets LHC

Energy Technology Data Exchange (ETDEWEB)

Hewett, JoAnne L.; /SLAC; Shelton, Jessie; /Yale U.; Spannowsky, Michael; /Oregon U.; Tait, Tim M.P.; /UC, Irvine; Takeuchi, Michihisa; /Heidelberg U.

2012-02-14

The recent Tevatron measurement of the forward-backward asymmetry of the top quark shows an intriguing discrepancy with Standard Model expectations, particularly at large t{bar t} invariant masses. Measurements of this quantity are subtle at the LHC, due to its pp initial state, however, one can define a forward-central-charge asymmetry which captures the physics. We study the capability of the LHC to measure this asymmetry and find that within the SM a measurement at the 5{sigma} level is possible with roughly 60 fb{sup -1} at {radical}s = 14 TeV. If nature realizes a model which enhances the asymmetry (as is necessary to explain the Tevatron measurements), a significant difference from zero can be observed much earlier, perhaps even during early LHC running at {radical}s = 7 TeV. We further explore the capabilities of the 7 TeV LHC to discover resonances or contact interactions which modify the t{bar t} invariant mass distribution using recent boosted top tagging techniques. We find that TeV-scale color octet resonances can be discovered, even with small coupling strengths and that contact interactions can be probed at scales exceeding 6 TeV. Overall, the LHC has good potential to clarify the situation with regards to the Tevatron forward-backward measurement.

Simulating climate with a synchronization-based supermodel

Science.gov (United States)

Selten, Frank M.; Schevenhoven, Francine J.; Duane, Gregory S.

2017-12-01

The SPEEDO global climate model (an atmosphere model coupled to a land and an ocean/sea-ice model with about 250.000 degrees of freedom) is used to investigate the merits of a new multi-model ensemble approach to the climate prediction problem in a perfect model setting. Two imperfect models are generated by perturbing parameters. Connection terms are introduced that synchronize the two models on a common solution, referred to as the supermodel solution. A synchronization-based learning algorithm is applied to the supermodel through the introduction of an update rule for the connection coefficients. Connection coefficients cease updating when synchronization errors between the supermodel and solutions of the "true" equations vanish. These final connection coefficients define the supermodel. Different supermodel solutions, but with equivalent performance, are found depending on the initial values of the connection coefficients during learning. The supermodels have a climatology and a climate response to a CO2 increase in the atmosphere that is closer to the truth as compared to the imperfect models and the standard multi-model ensemble average, showing the potential of the supermodel approach to improve climate predictions.

Proposal to negotiate a collaboration agreement for the design, testing and prototyping of superconducting elements for the High Luminosity LHC (HL-LHC) project and for the production of spare quadrupole magnets for LHC

CERN Document Server

2016-01-01

Proposal to negotiate a collaboration agreement for the design, testing and prototyping of superconducting elements for the High Luminosity LHC (HL-LHC) project and for the production of spare quadrupole magnets for LHC

Explosive transitions to synchronization in networks of phase oscillators.

Science.gov (United States)

Leyva, I; Navas, A; Sendiña-Nadal, I; Almendral, J A; Buldú, J M; Zanin, M; Papo, D; Boccaletti, S

2013-01-01

The emergence of dynamical abrupt transitions in the macroscopic state of a system is currently a subject of the utmost interest. The occurrence of a first-order phase transition to synchronization of an ensemble of networked phase oscillators was reported, so far, for very particular network architectures. Here, we show how a sharp, discontinuous transition can occur, instead, as a generic feature of networks of phase oscillators. Precisely, we set conditions for the transition from unsynchronized to synchronized states to be first-order, and demonstrate how these conditions can be attained in a very wide spectrum of situations. We then show how the occurrence of such transitions is always accompanied by the spontaneous setting of frequency-degree correlation features. Third, we show that the conditions for abrupt transitions can be even softened in several cases. Finally, we discuss, as a possible application, the use of this phenomenon to express magnetic-like states of synchronization.

Synchronization scenarios in the Winfree model of coupled oscillators

Science.gov (United States)

Gallego, Rafael; Montbrió, Ernest; Pazó, Diego

2017-10-01

Fifty years ago Arthur Winfree proposed a deeply influential mean-field model for the collective synchronization of large populations of phase oscillators. Here we provide a detailed analysis of the model for some special, analytically tractable cases. Adopting the thermodynamic limit, we derive an ordinary differential equation that exactly describes the temporal evolution of the macroscopic variables in the Ott-Antonsen invariant manifold. The low-dimensional model is then thoroughly investigated for a variety of pulse types and sinusoidal phase response curves (PRCs). Two structurally different synchronization scenarios are found, which are linked via the mutation of a Bogdanov-Takens point. From our results, we infer a general rule of thumb relating pulse shape and PRC offset with each scenario. Finally, we compare the exact synchronization threshold with the prediction of the averaging approximation given by the Kuramoto-Sakaguchi model. At the leading order, the discrepancy appears to behave as an odd function of the PRC offset.

LHC bending magnet coil

CERN Multimedia

A short test version of coil of wire used for the LHC dipole magnets. The high magnetic fields needed for guiding particles around the Large Hadron Collider (LHC) ring are created by passing 12’500 amps of current through coils of superconducting wiring. At very low temperatures, superconductors have no electrical resistance and therefore no power loss. The LHC is the largest superconducting installation ever built. The magnetic field must also be extremely uniform. This means the current flowing in the coils has to be very precisely controlled. Indeed, nowhere before has such precision been achieved at such high currents. Magnet coils are made of copper-clad niobium–titanium cables — each wire in the cable consists of 9’000 niobium–titanium filaments ten times finer than a hair.

High Multiplicity Searches at the LHC Using Jet Masses

Energy Technology Data Exchange (ETDEWEB)

Hook, Anson; /SLAC /Stanford U., Appl. Phys. Dept.; Izaguirre, Eder; /SLAC /Stanford U., Phys. Dept.; Lisanti, Mariangela; /Princeton U.; Wacker, Jay G.; /SLAC /Stanford U., ITP

2012-04-24

This article introduces a new class of searches for physics beyond the Standard Model that improves the sensitivity to signals with high jet multiplicity. The proposed searches gain access to high multiplicity signals by reclustering events into large-radius, or 'fat', jets and by requiring that each event has multiple massive jets. This technique is applied to supersymmetric scenarios in which gluinos are pair-produced and then subsequently decay to final states with either moderate quantities of missing energy or final states without missing energy. In each of these scenarios, the use of jet mass improves the estimated reach in gluino mass by 20% to 50% over current LHC searches.

Lag Synchronization Between Two Coupled Networks via Open-Plus-Closed-Loop and Adaptive Controls

International Nuclear Information System (INIS)

Tong-Chun Hu; Yong-Qing Wu; Shi-Xing Li

2016-01-01

In this paper, we study lag synchronization between two coupled networks and apply two types of control schemes, including the open-plus-closed-loop (OPCL) and adaptive controls. We then design the corresponding control algorithms according to the OPCL and adaptive feedback schemes. With the designed controllers, we obtain two theorems on the lag synchronization based on Lyapunov stability theory and Barbalat's lemma. Finally we provide numerical examples to show the effectiveness of the obtained controllers and see that the adaptive control is stronger than the OPCL control when realizing the lag synchronization between two coupled networks with different coupling structures. (paper)

Global synchronization in finite time for fractional-order neural networks with discontinuous activations and time delays.

Science.gov (United States)

Peng, Xiao; Wu, Huaiqin; Song, Ka; Shi, Jiaxin

2017-10-01

This paper is concerned with the global Mittag-Leffler synchronization and the synchronization in finite time for fractional-order neural networks (FNNs) with discontinuous activations and time delays. Firstly, the properties with respect to Mittag-Leffler convergence and convergence in finite time, which play a critical role in the investigation of the global synchronization of FNNs, are developed, respectively. Secondly, the novel state-feedback controller, which includes time delays and discontinuous factors, is designed to realize the synchronization goal. By applying the fractional differential inclusion theory, inequality analysis technique and the proposed convergence properties, the sufficient conditions to achieve the global Mittag-Leffler synchronization and the synchronization in finite time are addressed in terms of linear matrix inequalities (LMIs). In addition, the upper bound of the setting time of the global synchronization in finite time is explicitly evaluated. Finally, two examples are given to demonstrate the validity of the proposed design method and theoretical results. Copyright © 2017 Elsevier Ltd. All rights reserved.

The PS complex as proton pre-injector for the LHC - design and implementation report

International Nuclear Information System (INIS)

Benedikt, M.; Blas, A.; Borburgh, J.

2000-01-01

The LHC will be supplied with protons from the pre-injector chain comprising Linac2, PS Booster and PS. These accelerators have undergone a major upgrading programme during the last five years so as to meet the stringent requirements of the LHC. This implies that many high-intensity bunches of small emittance and tight spacing (25 ns) be available at the PS extraction energy (26 GeV/c). The upgrading project involved an increase of Linac2 current, new RF systems in the PS Booster and the PS, raising the PS Booster energy from 1 to 1.4 GeV, two-batch filling of the PS, and the installation of high-resolution beam profile measurement devices. With the project entering its final phase and most of the newly installed hardware now being operational, the emphasis switches to producing the nominal LHC beam and tackling the associated beam physics problems. This report describes all the hardware changes related to the upgrading project. (orig.)

Testing ATLAS diboson excess with dark matter searches at LHC

Energy Technology Data Exchange (ETDEWEB)

Liew, Seng Pei [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Shirai, Satoshi [Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg (Germany)

2015-11-27

The ATLAS collaboration has recently reported a 2.6σ excess in the search for a heavy resonance decaying into a pair of weak gauge bosons. Only fully hadronic final states are being looked for in the analysis. If the observed excess really originates from the gauge bosons’ decays, other decay modes of the gauge bosons would inevitably leave a trace on other exotic searches. In this paper, we propose the use of the Z boson decay into a pair of neutrinos to test the excess. This decay leads to a very large missing energy and can be probed with conventional dark matter searches at the LHC. We discuss the current constraints from the dark matter searches and the prospects. We find that optimizing these searches may give a very robust probe of the resonance, even with the currently available data of the 8 TeV LHC.

Testing ATLAS diboson excess with dark matter searches at LHC

International Nuclear Information System (INIS)

Liew, Seng Pei; Shirai, Satoshi

2015-01-01

The ATLAS collaboration has recently reported a 2.6σ excess in the search for a heavy resonance decaying into a pair of weak gauge bosons. Only fully hadronic final states are being looked for in the analysis. If the observed excess really originates from the gauge bosons’ decays, other decay modes of the gauge bosons would inevitably leave a trace on other exotic searches. In this paper, we propose the use of the Z boson decay into a pair of neutrinos to test the excess. This decay leads to a very large missing energy and can be probed with conventional dark matter searches at the LHC. We discuss the current constraints from the dark matter searches and the prospects. We find that optimizing these searches may give a very robust probe of the resonance, even with the currently available data of the 8 TeV LHC.

Testing ATLAS diboson excess with dark matter searches at LHC

Energy Technology Data Exchange (ETDEWEB)

Liew, Seng Pei [Tokyo Univ. (Japan). Dept. of Physics; Shirai, Satoshi [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2015-08-15

The ATLAS collaboration has recently reported a 2.6σ excess in the search for a heavy resonance decaying into a pair of weak gauge bosons. Only fully hadronic final states are being looked for in the analysis. If the observed excess really originates from the gauge bosons' decays, other decay modes of the gauge bosons would inevitably leave a trace on other exotic searches. In this paper, we propose the use of the Z boson into a pair of neutrinos to test the excess. This decay leads to a very large missing energy and can be probed with conventional dark matter searches at the LHC. We discuss the current constraints from the dark matter searches and the prospects. We find that optimizing these searches may give a very robust probe of the resonance, even with the currently available data of the 8 TeV LHC.

LHC Report: Back in operation

CERN Multimedia

2016-01-01

With the machine back in their hands since Friday, 4 March, the LHC operators are now performing the powering tests on the magnets. This is a crucial step before receiving the first beams and restarting Run 2 for physics.   A Distribution Feed-Box (DFB) brings power to the LHC magnets and maintains the stability of the current in the superconducting circuits. The LHC was the last machine to be handed back to operators after the completion of maintenance work carried out during the Year-End Technical Stop (YETS) that had started on 14 December 2015. During the eleven weeks of scheduled maintenance activities, several operations took place in all the accelerators and beam lines. They included the maintenance in several points of the cryogenic system, the replacement of 18 magnets in the Super Proton Synchrotron; an extensive campaign to identify and remove thousands of obsolete cables; the replacement of the LHC beam absorbers for injection (TDIs) that are used to absorb the SPS b...

Keeping the LHC in power

CERN Multimedia

CERN Bulletin

2013-01-01

The critical safety equipment around the LHC, including the machine protection systems, is connected to Uninterruptible Power Supplies (UPS).  In case of mains failure, the UPS systems continue to power, for a limited time, these critical systems and ensure a safe shutdown of the accelerator. This week, work began to upgrade and replace over 100 UPS systems in the LHC.   The new UPS installations. For the LHC, even a perturbation on the mains is more than just an inconvenience: it often results in beam dumps and, in some cases, requires an energy extraction from superconducting circuits. When this occurs, machine protection systems, and in particular the Quench Protection System, must remain active to correctly carry out the shutdown procedure. With the UPS systems, 10 minutes of crucial power can be provided to the protection systems during this critical phase. There are currently two UPS systems in place in each one of the 32 LHC UPS zones. Originally one was used as a backup if ...

Generalized Mutual Synchronization between Two Controlled Interdependent Networks

Directory of Open Access Journals (Sweden)

Quan Xu

2014-01-01

Full Text Available This paper mainly focuses on the generalized mutual synchronization between two controlled interdependent networks. First, we propose the general model of controlled interdependent networks A and B with time-varying internetwork delays coupling. Then, by constructing Lyapunov functions and utilizing adaptive control technique, some sufficient conditions are established to ensure that the mutual synchronization errors between the state variables of networks A and B can asymptotically converge to zero. Finally, two numerical examples are given to illustrate the effectiveness of the theoretical results and to explore potential application in future smart grid. The simulation results also show how interdependent topologies and internetwork coupling delays influence the mutual synchronizability, which help to design interdependent networks with optimal mutual synchronizability.

Tapping Into Rate Flexibility: Musical Training Facilitates Synchronization Around Spontaneous Production Rates

Science.gov (United States)

Scheurich, Rebecca; Zamm, Anna; Palmer, Caroline

2018-01-01

The ability to flexibly adapt one’s behavior is critical for social tasks such as speech and music performance, in which individuals must coordinate the timing of their actions with others. Natural movement frequencies, also called spontaneous rates, constrain synchronization accuracy between partners during duet music performance, whereas musical training enhances synchronization accuracy. We investigated the combined influences of these factors on the flexibility with which individuals can synchronize their actions with sequences at different rates. First, we developed a novel musical task capable of measuring spontaneous rates in both musicians and non-musicians in which participants tapped the rhythm of a familiar melody while hearing the corresponding melody tones. The novel task was validated by similar measures of spontaneous rates generated by piano performance and by the tapping task from the same pianists. We then implemented the novel task with musicians and non-musicians as they synchronized tapping of a familiar melody with a metronome at their spontaneous rates, and at rates proportionally slower and faster than their spontaneous rates. Musicians synchronized more flexibly across rates than non-musicians, indicated by greater synchronization accuracy. Additionally, musicians showed greater engagement of error correction mechanisms than non-musicians. Finally, differences in flexibility were characterized by more recurrent (repetitive) and patterned synchronization in non-musicians, indicative of greater temporal rigidity. PMID:29681872

Tapping Into Rate Flexibility: Musical Training Facilitates Synchronization Around Spontaneous Production Rates

Directory of Open Access Journals (Sweden)

Rebecca Scheurich

2018-04-01

Full Text Available The ability to flexibly adapt one’s behavior is critical for social tasks such as speech and music performance, in which individuals must coordinate the timing of their actions with others. Natural movement frequencies, also called spontaneous rates, constrain synchronization accuracy between partners during duet music performance, whereas musical training enhances synchronization accuracy. We investigated the combined influences of these factors on the flexibility with which individuals can synchronize their actions with sequences at different rates. First, we developed a novel musical task capable of measuring spontaneous rates in both musicians and non-musicians in which participants tapped the rhythm of a familiar melody while hearing the corresponding melody tones. The novel task was validated by similar measures of spontaneous rates generated by piano performance and by the tapping task from the same pianists. We then implemented the novel task with musicians and non-musicians as they synchronized tapping of a familiar melody with a metronome at their spontaneous rates, and at rates proportionally slower and faster than their spontaneous rates. Musicians synchronized more flexibly across rates than non-musicians, indicated by greater synchronization accuracy. Additionally, musicians showed greater engagement of error correction mechanisms than non-musicians. Finally, differences in flexibility were characterized by more recurrent (repetitive and patterned synchronization in non-musicians, indicative of greater temporal rigidity.

LS1 general planning and strategy for the LHC, LHC injectors

CERN Document Server

Foraz, K

2012-01-01

The goal of Long Shutdown 1 (LS1) is to perform the full maintenance of equipment, and the necessary consolidation and upgrade activities in order to ensure reliable LHC operation at nominal performance from mid 2014. LS1 not only concerns LHC but also its injectors. To ensure resources will be available an analysis is in progress to detect conflict/overload and decide what is compulsary, what we can afford, and what can be postponed to LS2. The strategy, time key drivers, constraints, and draft schedule will be presented here.

First LHC beam in 2017

CERN Multimedia

ATLAS Collaboration

2017-01-01

Impressions from the ATLAS control room while waiting for the very first 2017 LHC beams, from the traditional croissants in the morning to the "beam splashes" in the evening. The shift crew, online experts, run coordinators and management are looking forward to the next steps of the LHC restart.

First LHC beam in 2017

CERN Multimedia

ATLAS Collaboration

2017-01-01

Impressions from the ATLAS control room while waiting for the very first 2017 LHC beams, from the traditional croissants in the morning to the "beam splashes" in the evening. The shift crew, online experts, run coordinators and management are looking forward the next steps of the LHC restart.

Gravitino LSP scneario at the LHC

International Nuclear Information System (INIS)

Heisig, Jan

2010-05-01

In this thesis we discuss the phenomenology of the gravitino LSP scenario at the large hadron collider (LHC) experiment. We concentrate on a long-lived stau NLSP which gives rise to a prominent signature in the LHC detector as a 'slow muon'. We discuss the production channels and compute the cross sections for direct production via the Drell-Yan process. On this basis we claim a conservative estimation of the discovery potential for this scenario at the LHC. (orig.)

Fast sparsely synchronized brain rhythms in a scale-free neural network.

Science.gov (United States)

Kim, Sang-Yoon; Lim, Woochang

2015-08-01

statistically homogeneous random graphs and small-world networks. Finally, we investigate the effect of network architecture on sparse synchronization for fixed values of J and D in the following three cases: (1) variation in the degree of symmetric attachment, (2) asymmetric preferential attachment of new nodes with different in- and out-degrees, and (3) preferential attachment between pre-existing nodes (without addition of new nodes). In these three cases, both relation between network topology (e.g., average path length and betweenness centralization) and sparse synchronization and contributions of individual dynamics to the sparse synchronization are discussed.

Fast sparsely synchronized brain rhythms in a scale-free neural network

Science.gov (United States)

Kim, Sang-Yoon; Lim, Woochang

2015-08-01

random graphs and small-world networks. Finally, we investigate the effect of network architecture on sparse synchronization for fixed values of J and D in the following three cases: (1) variation in the degree of symmetric attachment, (2) asymmetric preferential attachment of new nodes with different in- and out-degrees, and (3) preferential attachment between pre-existing nodes (without addition of new nodes). In these three cases, both relation between network topology (e.g., average path length and betweenness centralization) and sparse synchronization and contributions of individual dynamics to the sparse synchronization are discussed.

LHC Dipoles Accelerate

CERN Multimedia

2001-01-01

Andrezej Siemko (left), Peter Sievers (centre), and Lucio Rossi (right), have the exciting challenge of preparing and testing 2000 magnets for the LHC. The LHC is going to require a lot of powerful magnets by the time it begins operation in 2006. More specifically, it is going to need 130 special magnets, 400 quadrupoles, and a whopping 1250 dipoles! Preparing and testing these magnets for the conditions they will encounter in the LHC is not an easy task. But evaluation of the most recently received magnet, from the German company Noell, is showing that while the monumental task of receiving and testing nearly 2000 magnets is going to be exhausting, the goals are definitely attainable. At the moment and over the next year, pre-series magnets (the magnets that CERN uses to fine tune performance) are arriving slowly (90 in total will arrive), but by 2003 the rate of series magnet arrival will accelerate to 9 per week, that's over 450 in a single year! And working with these magnets when they arrive is tough. ...

The Physics Landscape of the High Luminosity LHC

CERN Document Server

Mangano, M

2015-01-01

We review the status of HEP after the first run of the LHC and discuss the opportunities offered by the HL-LHC, in light of the needs for future progress that are emerging from the data. The HL-LHC will push to the systematic limit the precision of most measurements of the Higgs boson, and will be necessary to firmly establish some of the more rare decays foreseen by the Standard Model, such as the decays to dimuons and to a Z+ photon pair. The HL-LHC luminosity will provide additional statistics required by the quantitative study of any discovery the LHC may achieve during the first 300 inverse femtobarn, and will further extend the discovery potential of the LHC, particularly for rare, elusive or low-sensitivity processes.

The CMS Outer Tracker for HL-LHC

CERN Document Server

Dierlamm, Alexander Hermann

2018-01-01

The LHC is planning an upgrade program, which will bring the luminosity to about $5-7\\times10^{34}$~cm$^{-2}$s$^{-1}$ in 2026, with a goal of an integrated luminosity of 3000 fb$^{-1}$ by the end of 2037. This High Luminosity LHC scenario, HL-LHC, will require a preparation program of the LHC detectors known as Phase-2 Upgrade. The current CMS Tracker is already running beyond design specifications and will not be able to cope with the HL-LHC radiation conditions. CMS will need a completely new Tracker in order to fully exploit the highly demanding operating conditions and the delivered luminosity. The new Outer Tracker system is designed to provide robust tracking as well as Level-1 trigger capabilities using closely spaced modules composed of silicon macro-pixel and/or strip sensors. Research and development activities are ongoing to explore options and develop module components and designs for the HL-LHC environment. The design choices for the CMS Outer Tracker Upgrade are discussed along with some highlig...

1754 Days to the LHC and counting!

CERN Multimedia

2001-01-01

At the 118th session of CERN Council, held on Friday 15 June under the chairmanship of Professor Maurice Bourquin of Switzerland, Director-General, Luciano Maiani, presented the commissioning schedule for the Large Hadron Collider (LHC) for the first time. The LHC will collide its first beams in a pilot run starting on 1 April 2006. 'We are 1754 days from the LHC', said Professor Maiani. A full seven-month physics run will begin in August 2006, and the LHC's heavy-ion programme will start in February 2007. Left to right: Lyn Evans, Luciano Maiani, Alexander Skrinsky, and Kurt Hubner with the magnets from Novosibirsk. Professor Maiani underlined to Council that the LHC is now CERN's most important single activity, accounting for over 70% of the Laboratory's resources. Moreover, with some 70% of the total LHC cost adjudicated and 30% paid, the project is very far advanced. With the adjudication this Autumn of the contracts for the 1236 fifteen metre superconducting dipole magnets, the placing of major contrac...

Content-based intermedia synchronization

Science.gov (United States)

Oh, Dong-Young; Sampath-Kumar, Srihari; Rangan, P. Venkat

1995-03-01

Inter-media synchronization methods developed until now have been based on syntactic timestamping of video frames and audio samples. These methods are not fully appropriate for the synchronization of multimedia objects which may have to be accessed individually by their contents, e.g. content-base data retrieval. We propose a content-based multimedia synchronization scheme in which a media stream is viewed as hierarchial composition of smaller objects which are logically structured based on the contents, and the synchronization is achieved by deriving temporal relations among logical units of media object. content-based synchronization offers several advantages such as, elimination of the need for time stamping, freedom from limitations of jitter, synchronization of independently captured media objects in video editing, and compensation for inherent asynchronies in capture times of video and audio.

Synchronizing strict-feedback and general strict-feedback chaotic systems via a single controller

International Nuclear Information System (INIS)

Chen Shihua; Wang Feng; Wang Changping

2004-01-01

We present a systematic design procedure to synchronize a class of chaotic systems in a so-called strict-feedback form based on back-stepping procedure. This approach needs only a single controller to realize synchronization no matter how many dimensions the chaotic system contains. Furthermore, we point out that the method does not work for general strict-feedback chaotic systems, for instance, Lorenz system. Therefore, we propose three kinds of synchronization schemes for Lorenz system using the Lyapunov function method. All the three schemes avoid including divergence factor as in Ref. [Chaos, Solitons and Fractals 16 (2003) 37]. Especially in the last two schemes, we need only one state variable in controller, which has important significance in chaos synchronization used for communication purposes. Finally numerical simulations are provided to show the effectiveness and feasibility of the developed methods

LHC Report: The machine under maintenance

CERN Multimedia

Katy Foraz for the LHC Team

2012-01-01

The LHC Christmas break started on 12 December. Since then, teams have been working hard to complete all the maintenance work planned to ensure the reliable operation of the LHC in 2012.   Installation of shielding at Point 1. The maintenance work is being carried out on key infrastructure such as the cooling, ventilation, electricity and safety systems. Maintenance work is being carried out not just in the LHC but also across the whole accelerator complex, which makes planning the work even more complicated. At the time of going to print, 50% of the cryogenics system maintenance has been finished, which, according to the schedule, will allow the LHC teams to start cooling down the first sectors next week to have the entire machine cold by the end of February. A lot of activity is going on in order to mitigate the effects of radiation on equipment installed in the LHC tunnel and underground areas during 2012 operation. To this end, teams have installed additional shielding at Point 1 (see ph...

LHC Power Converters: A Precision Game

CERN Multimedia

2001-01-01

The LHC test-bed, String 2, is close to commissioning and one important element to get a first chance to prove what it can do is the power converter system. In String 2 there are 16 converters, in the full LHC there will be almost 1800. This article takes a look at what is so special about the power converters for the LHC. The 13 000 Amps power converters with the watercooled cables going to the String 2 feedboxes. The LHC's superconducting magnets will be the pinnacle of high technology. But to work, they'll need the help of high-precision power converters to supply them with extremely stable DC current. Perfection will be the name of the game, with an accuracy of just 1-2 parts per million (ppm) required. LEP, for the sake of comparison, could live with 10-20 ppm. The LHC's power converters will be very different from those of LEP or the SPS since the new accelerator's magnets are mostly superconducting. That means that they require much higher currents at a lower voltage since superconductors have no re...

Prototype HL-LHC magnet undergoes testing

CERN Multimedia

Corinne Pralavorio

2016-01-01

A preliminary short prototype of the quadrupole magnets for the High-Luminosity LHC has passed its first tests.   The first short prototype of the quadrupole magnet for the High Luminosity LHC. (Photo: G. Ambrosio (US-LARP and Fermilab), P. Ferracin and E. Todesco (CERN TE-MSC)) Momentum is gathering behind the High-Luminosity LHC (HL-LHC) project. In laboratories on either side of the Atlantic, a host of tests are being carried out on the various magnet models. In mid-March, a short prototype of the quadrupole magnet underwent its first testing phase at the Fermilab laboratory in the United States. This magnet is a pre-prototype of the quadrupole magnets that will be installed near to the ATLAS and CMS detectors to squeeze the beams before collisions. Six quadrupole magnets will be installed on each side of each experiment, giving a total of 24 magnets, and will replace the LHC's triplet magnets. Made of superconducting niobium-tin, the magnets will be more powerful than their p...

High Luminosity LHC: challenges and plans

Science.gov (United States)

Arduini, G.; Barranco, J.; Bertarelli, A.; Biancacci, N.; Bruce, R.; Brüning, O.; Buffat, X.; Cai, Y.; Carver, L. R.; Fartoukh, S.; Giovannozzi, M.; Iadarola, G.; Li, K.; Lechner, A.; Medina Medrano, L.; Métral, E.; Nosochkov, Y.; Papaphilippou, Y.; Pellegrini, D.; Pieloni, T.; Qiang, J.; Redaelli, S.; Romano, A.; Rossi, L.; Rumolo, G.; Salvant, B.; Schenk, M.; Tambasco, C.; Tomás, R.; Valishev, S.; Van der Veken, F. F.

2016-12-01