CERN: Higher energies at LEP

International Nuclear Information System (INIS)

Anon.

1995-01-01

This year will be the last that CERN's 27-kilometre LEP electron-positron collider will run routinely at around 45 GeV per beam. In the run, scheduled to begin in May, the four big experiments will top up their harvest so far of over 12 million Z particles for a final polishing of precision Z data. Behind the scenes, LEP is being prepared for higher energy running and a new phase of physics. After a brief technical stop in October, the aim is for a test run of up to 70 GeV per beam before the end of the year. Higher energy demands more radiofrequency power, which will be supplied by superconducting cavities. With this goal in mind, a programme of development work began at CERN over ten years ago, when LEP was still on the drawing board. Initially this effort focused on cavities made from sheet niobium, but later switched to copper covered by a sputtered niobium film, which gives better thermal and r.f. performance (September 1990, page 24). The first industrially-manufactured four-cavity niobium coated module, complete with its cryostat and r.f plumbing, was installed in LEP in 1993. Although it quickly achieved its nominal accelerating gradient of 6 MV/m, its reliability was affected by unforeseen problems in the associated power couplers. This delayed the installation schedule, but after a crash programme of design and modification of the power couplers, together with improvements in actual cavity design and manufacture, module supply and testing has now attained a satisfactory rhythm. Two modules installed in LEP amassed between them over 50 days of continuous running in 1994, and confidence is now high that the emphasis can shift towards integrating the cavities into LEP, rather than running the cavities themselves. During LEP's 1994-5 winter shutdown, modules are being installed at Points 2 and 6. Later, additional cavities will be installed in Points 2, 6 and 8 prior to embarking on the higher energy test run at the end of the year. After

Groundbreaking for LEP

International Nuclear Information System (INIS)

Anon.

1983-01-01

On 13 September, CERN found itself once more in the international spotlight when President Frangois Mitterrand of France and President Pierre Aubert of Switzerland arrived for the official 'groundbreaking' ceremony for the 27-kilometre ring of the LEP electron-positron collider. As well as the Presidents of the two CERN host states under whose territory LEP will be constructed, there were ranking representatives of the CERN Member States, together with those of other countries who will take part in the first LEP experiments, expanding further the already large community of CERN users

CERN: End of LEP's Z era

Energy Technology Data Exchange (ETDEWEB)

Anon.

1995-11-15

Full text: Achapter of history at CERN's LEP electron-positron collider closed in October when the four big experiments, Aleph, Delphi, L3 and Opal, logged their final data at the Z energy, just over six years after LEP's first Z was detected. The LEP Z era has been one of great success, both in terms of physics results and the advances which have been made with the machine itself. LEP now takes a step towards becoming LEP2, when the energy is wound up from around 45 GeV to about 70 GeV per beam (September, page 6). By the end of LEP's 1995 run, each of the four LEP experiments had seen almost five million Zs. Now the spotlight at LEP shifts to producing pairs of W particles, the electrically charged counterparts of the Z. LEP's first Zs were recorded in August 1989, one month after the machine's first circulating beam. The 30,000 Z decays recorded by each experiment in 1989 confirmed that matter comes in just three distinct families of quarks and leptons. The values of the Z mass and width quoted in 1990 were 91.161 ± 0.031 GeV and 2.534 ± 0.027 GeV. By the beginning of 1995, these had been fine-tuned to the extraordinary accuracy of 91.1884 ± 0.0022 GeV and 2.4963 ± 0.0032 GeV, and when data from this year's run is included, will be even better. These results, combined with precision data from neutrino experiments and from Fermilab's Tevatron protonantiproton collider, have put the Standard Model of quarks and leptons through its most gruelling test yet. Right from the start, collaboration between LEP experiments and the accelerator team has been close, with frequent scheduling meetings determining how the machine is run. For the first few years, LEP ran on a diet of four bunches of electrons and four of positrons, but by the end of 1992, a way had been found to increase the luminosity by squeezing in more bunches. In 1993, the 'pretzel' scheme (October 1992, page 17), so called because of the shape traced out by the circulating beams, was running with eight

LEP beampipe section

CERN Multimedia

1989-01-01

Short section of beampipe from the Large Electron Positron collider (LEP, for short). With its 27-kilometre circumference, LEP was the largest electron-positron accelerator ever built and ran from 1989 to 2000 at CERN. During 11 years of research, LEP's experiments provided a detailed study of the electroweak interaction. Measurements performed at LEP also proved that there are three – and only three – generations of particles of matter. LEP was closed down on 2 November 2000 to make way for the construction of the Large Hadron Collider in the same tunnel.

LEP tunnel monorail

CERN Multimedia

1985-01-01

A monorail from CERN's Large Electron Positron collider (LEP, for short). It ran around the 27km tunnel, transporting equipment and personnel. With its 27-kilometre circumference, LEP was the largest electron-positron accelerator ever built and ran from 1989 to 2000. During 11 years of research, LEP's experiments provided a detailed study of the electroweak interaction. Measurements performed at LEP also proved that there are three – and only three – generations of particles of matter. LEP was closed down on 2 November 2000 to make way for the construction of the Large Hadron Collider in the same tunnel.

LEP Inauguration

International Nuclear Information System (INIS)

Anon.

1989-01-01

On 13 November, Heads of State, Heads of Government and Ministers from CERN's 14 Member States, together with more than a thousand invited guests, attended the inauguration ceremony of LEP, CERN's new 27-kilometre electron-positron collider

The design, construction and commissioning of the CERN Large Electron-Positron collider

International Nuclear Information System (INIS)

Myers, S.; Picasso, E.

1990-01-01

A description is given of the most important parameters considered in the design of the CERN Large Electron-Positron collider. It is shown how these parameters affect the collider performance and how they have been optimised with respect to the cost of the project. The functioning of each major subsystem is described with respect to its role as part of the collider. Finally, the planning, testing and initial commissioning of LEP is described and possible future developments are outlined. (author)

Focus on LEP

Energy Technology Data Exchange (ETDEWEB)

Anon.

1986-12-15

When it begins operations early in 1989, the LEP electron-positron Collider now being built at CERN will provide beams of some 60 GeV (120 GeV collision energy). However with superconducting radiofrequency acceleration equipment complementing the conventional units, the beam energy eventually could be boosted to about 100 GeV per beam. In parallel with LEP construction, a vigorous development programme for these superconducting cavities has been underway at CERN.

Focus on LEP

International Nuclear Information System (INIS)

Anon.

1986-01-01

When it begins operations early in 1989, the LEP electron-positron Collider now being built at CERN will provide beams of some 60 GeV (120 GeV collision energy). However with superconducting radiofrequency acceleration equipment complementing the conventional units, the beam energy eventually could be boosted to about 100 GeV per beam. In parallel with LEP construction, a vigorous development programme for these superconducting cavities has been underway at CERN

CERN strives to stay ahead

International Nuclear Information System (INIS)

Sutton, Christine.

1987-01-01

The paper examines the future of CERN, with respect to its proposed research programme and its need to save money. Proposals concerning what accelerators CERN should build for the future are outlined; machines such as the Large Hadron Collider and the CERN Linear Collider have been proposed. Experimental expectations for the first Large Electron Positron (LEP) collider (now close to completion) are briefly described, along with the experimental investigations for the second phase of operation of LEP where modifications will increase the machine's energy. Criticisms of CERN's management by its governing body are also discussed. (UK)

CERN LEP2 constraint on 4D QED having a dynamically generated spatial dimension

International Nuclear Information System (INIS)

Cho, G.-C.; Izumi, Etsuko; Sugamoto, Akio

2002-01-01

We study 4D QED in which one spatial dimension is dynamically generated from the 3D action, following the mechanism proposed by Arkani-Hamed, Cohen, and Georgi. In this model, the generated fourth dimension is discretized by an interval parameter a. We examine the phenomenological constraint on the parameter a coming from collider experiments on the QED process e + e - →γγ. It is found that the CERN e + e - collider LEP2 experiments give the constraint of 1/a > or approx. 461 GeV. The expected bound on the same parameter a at a future e + e - linear collider is briefly discussed

Collide@CERN Geneva

CERN Multimedia

CERN. Geneva; Kieffer, Robert; Blas Temino, Diego; Bertolucci, Sergio; Mr. Decelière, Rudy; Mr. Hänni, Vincent

2014-01-01

CERN, the Republic and Canton of Geneva, and the City of Geneva are delighted to invite you to “Collide@CERN Geneva Music”. Come to the public lecture about collisions between music and particle physics by the third winners of Collide@CERN Geneva, Vincent Hänni & Rudy Decelière, and their scientific inspiration partners, Diego Blas and Robert Kieffer. The event marks the beginning of their residency at CERN, and will be held at the CERN Globe of Science and Innovation on 16 October 2014 at 19.00. Doors will open at 18.30.

CERN: End of LEP's Z era

International Nuclear Information System (INIS)

Anon.

1995-01-01

Full text: Achapter of history at CERN's LEP electron-positron collider closed in October when the four big experiments, Aleph, Delphi, L3 and Opal, logged their final data at the Z energy, just over six years after LEP's first Z was detected. The LEP Z era has been one of great success, both in terms of physics results and the advances which have been made with the machine itself. LEP now takes a step towards becoming LEP2, when the energy is wound up from around 45 GeV to about 70 GeV per beam (September, page 6). By the end of LEP's 1995 run, each of the four LEP experiments had seen almost five million Zs. Now the spotlight at LEP shifts to producing pairs of W particles, the electrically charged counterparts of the Z. LEP's first Zs were recorded in August 1989, one month after the machine's first circulating beam. The 30,000 Z decays recorded by each experiment in 1989 confirmed that matter comes in just three distinct families of quarks and leptons. The values of the Z mass and width quoted in 1990 were 91.161 ± 0.031 GeV and 2.534 ± 0.027 GeV. By the beginning of 1995, these had been fine-tuned to the extraordinary accuracy of 91.1884 ± 0.0022 GeV and 2.4963 ± 0.0032 GeV, and when data from this year's run is included, will be even better. These results, combined with precision data from neutrino experiments and from Fermilab's Tevatron protonantiproton collider, have put the Standard Model of quarks and leptons through its most gruelling test yet. Right from the start, collaboration between LEP experiments and the accelerator team has been close, with frequent scheduling meetings determining how the machine is run. For the first few years, LEP ran on a diet of four bunches of electrons and four of positrons, but by the end of 1992, a way had been found to increase the luminosity by squeezing in more bunches. In 1993, the 'pretzel' scheme (October 1992, page 17), so called because of the shape traced out by

CERN: LEP delivers; Looking deeper at spin; Handling low energy antiprotons

Energy Technology Data Exchange (ETDEWEB)

Anon.

1990-03-15

One year ago, with the world catalogue of Z particles - the electrically neutral carrier of the weak nuclear force - containing a few hundred examples, it sounded extravagant when proponents of CERN's new LEP electron-positron collider promised a hundred thousand Zs by Christmas 1989. The first round of experiments in the North Area of CERN's SPS proton synchrotron included a considerable investment in studies using high energy muon beams. This paid off with important contribuions to physics, particularly in the measurement of the quark/gluon content (structure functions) of nucleons. ; The LEAR low energy antiproton ring at CERN takes its antimatter beams down to very low kinetic energies - less than 10 MeV - for a unique range of physics studies. However even these modest energies are too high for a series of experiments aiming to explore the effects of gravity on antimatter.

Raising the last LEP dipole

CERN Multimedia

Maximilien Brice

2002-01-01

The last of the 3280 dipole magnets from the Large Electron-Positron (LEP) collider is seen on its journey to the surface on 12 February 2002. The LEP era, which began at CERN in 1989 and ended 2000, comes to an end.

LEP experiments take shape

Energy Technology Data Exchange (ETDEWEB)

Anon.

1986-05-15

Excavation of the 27 kilometre tunnel and vast underground caverns for CERN's new LEP electronpositron collider is forging ahead, and equipment for the machine is arriving on the site in increasing quantities ready to attack the huge task of installation. At about the same time that LEP construction work began at CERN in 1983, physicists from some hundred research centres throughout the world began gearing up for the detailed design, construction and testing of the millions of components for the four big detectors – ALEPH, DELPHI, L3 and OPAL – which will study LEP's electron-positron collisions.

LEP experiments take shape

International Nuclear Information System (INIS)

Anon.

1986-01-01

Excavation of the 27 kilometre tunnel and vast underground caverns for CERN's new LEP electronpositron collider is forging ahead, and equipment for the machine is arriving on the site in increasing quantities ready to attack the huge task of installation. At about the same time that LEP construction work began at CERN in 1983, physicists from some hundred research centres throughout the world began gearing up for the detailed design, construction and testing of the millions of components for the four big detectors – ALEPH, DELPHI, L3 and OPAL – which will study LEP's electron-positron collisions

CERN: LEP to higher energy/LHC magnet string test

International Nuclear Information System (INIS)

Anon.

1995-01-01

At 19.45 on 31 October, CERN's LEP electron-positron collider, equipped with superconducting radiofrequency accelerating cavities, registered its first events at a record collision energy of 130 GeV. During November, LEP went on to operate in the 130-140 GeV collision energy range. Fabrication and installation of the superconducting radiofrequency accelerating cavities needed to boost the energy of LEP's electron and positron beams have speeded up as confidence and expertise have increased. 16 additional cavities were installed in a brief technical stop during October. For the substantially upgraded machine to supply 65 GeV beams immediately and at luminosities comparable to those routinely attained before shows that the complicated technology needed for the superconducting cavities and mastering the machine itself are well under control - yet another remarkable achievement in CERN's tradition of remarkable achievements. Before the end-1995 run, LEP had been operating around the Z resonance at 91 GeV ever since its commissioning in 1989. LEP precision data on the Z, the electrically neutral carrier of the weak nuclear force, is now complete, and attention shifts toward the next major objective, accumulating data on the W, the Z's electrically charged counterpart. Unlike the Z, produced singly in electron-positron annihilations, the electrically charged Ws have to be produced in pairs. During the coming long shutdown, more superconducting modules will be installed to prepare for recommencement of operations in June, this time at collision energies of 161 GeV, allowing a first step across a longawaited 2W threshold. Later in the year more cavities will be ready to boost collision energies to 176 GeV. However in the meantime the LEP experiments, no longer blinded by the Z resonance, will be keeping a sharp eye open for new physics, and in particular for signs of as yet unseen supersymmetric particles. Theorists have long been convinced that our

CERN: LEP delivers; Looking deeper at spin; Handling low energy antiprotons

International Nuclear Information System (INIS)

Anon.

1990-01-01

One year ago, with the world catalogue of Z particles - the electrically neutral carrier of the weak nuclear force - containing a few hundred examples, it sounded extravagant when proponents of CERN's new LEP electron-positron collider promised a hundred thousand Zs by Christmas 1989. The first round of experiments in the North Area of CERN's SPS proton synchrotron included a considerable investment in studies using high energy muon beams. This paid off with important contribuions to physics, particularly in the measurement of the quark/gluon content (structure functions) of nucleons. ; The LEAR low energy antiproton ring at CERN takes its antimatter beams down to very low kinetic energies - less than 10 MeV - for a unique range of physics studies. However even these modest energies are too high for a series of experiments aiming to explore the effects of gravity on antimatter

CERN: LEP in the Alps

International Nuclear Information System (INIS)

Anon.

1993-01-01

Full text: In January, when CERN's LEP electron-positron collider is enjoying a well-earned break, it has now become traditional for the hard pressed LEP team to have no respite. Instead they pack their bags and depart for Chamonix in the nearby French Alps to review the past year's experience and plan for the future. In the cold January 1993 light of Chamonix, 1992 (January/February, page 4) was deemed to have been a good year for LEP operations, with the switch to 90° betatron phase operation having paid off. The 65% improvement in integrated luminosity over 1991 was attributed to longer beam lifetimes, faster filling and improved overall efficiency. The commissioning of the eight-bunch 'pretzel' scheme was facilitated with the new optics, and break-even quickly achieved, so that physics could benefit from more bunches in the machine. During 1992, the injection chain was fully tested with eight bunches, and when this comes into routine operation this year, the pretzel scheme will benefit. Pretzel running also opens the possibility of still higher luminosity, up to 2x10 31 per sq cm per s, doubling the present level. However the finishing touches to high luminosity running are still more an art ('haute cuisine') than a science. Continuing studies of the inter correlation of different LEP conditions will help make this more systematic. The main factors affecting performance at 45 GeV are transverse mode coupling instabilities. The present working point gives good results, but there are still potentially interesting regions which need to be checked out. Beam lifetime and background are both limited by beam size and aperture. Background was reduced by improved focusing, while beam size is dominated by beam-beam effects. 90° operation proved its worth in 1992, but the inability to produce polarized beams was a disappointment, and a combined 90°/60° horizontal/vertical combination looked like offering the best of both worlds. Although

CERN: A hinge between LEP and the LHC

International Nuclear Information System (INIS)

Anon.

1995-01-01

Later this year, if all goes well, the beam energy of CERN's LEP electron-positron collider should be increased to around 70 GeV per beam (collision energy 140 GeV), giving a foretaste of things to come. Since 1989, the 27-kilometre ring has been operating around 45 GeV per beam to feed its four physics experiments with a steady diet of Z particles, the electrically neutral carriers of the weak nuclear force. This has given precision results on vital parameters of the Standard Model. Meanwhile work has been steadily pushing ahead to upgrade LEP to LEP2, installing superconducting radiofrequency cavities (January 1994, page 6) and ancillary cryogenics equipment to boost the machine's energy and reach new areas of physics interest. The initial goal is to produce pairs of W particles, the electrically charged counterparts of the Z. As far as the machine is concerned, at these higher energies, the 'beambeam' interaction between the contra-rotating electrons and positrons is reduced, so more particles can be pumped into the ring. To achieve this, LEP has switched to the new 'bunch train' scheme (see page 14) each train containing several 'carriages' (bunches) of particles. To attain its physics objectives, LEP2's target is 500 inverse picobarns of integrated luminosity over the next few years. This is a challenge as LEP's integrated luminosity to date (since the machine was commissioned in 1989) is some 160 inverse picobarns, itself viewed as no mean achievement. To reach higher energies, the accelerating power at LEP is being increased with installation of superconducting radiofrequency cavities. After initial trials with solid niobium, LEP2 relies on the more reliable performance provided by copper, with its better heat conduction properties, coated with a superconducting film of niobium. Even so heroic preprocessing is required to ensure optimal performance. After initial trials revealed welding weaknesses, the

LEP inauguration

Energy Technology Data Exchange (ETDEWEB)

Anon.

1990-01-15

13 November saw the culmination at CERN of weeks of intricate planning to put together a fitting formal inauguration of LEP, CERN's 27-kilometre electron-positron collider. The day was to witness an event worthy of the many years of assiduous endeavour to bring into being the world's largest scientific machine, a prime example of international collaboration and the portent of a new era in fundamental research.

LEP inauguration

International Nuclear Information System (INIS)

Anon.

1990-01-01

13 November saw the culmination at CERN of weeks of intricate planning to put together a fitting formal inauguration of LEP, CERN's 27-kilometre electron-positron collider. The day was to witness an event worthy of the many years of assiduous endeavour to bring into being the world's largest scientific machine, a prime example of international collaboration and the portent of a new era in fundamental research.

Controls for the CERN large hadron collider (LHC)

International Nuclear Information System (INIS)

Kissler, K.H.; Perriollat, F.; Rabany, M.; Shering, G.

1992-01-01

CERN's planned large superconducting collider project presents several new challenges to the Control System. These are discussed along with current thinking as to how they can be met. The high field superconducting magnets are subject to 'persistent currents' which will require real time measurements and control using a mathematical model on a 2-10 second time interval. This may be realized using direct links, multiplexed using TDM, between the field equipment and central servers. Quench control and avoidance will make new demands on speed of response, reliability and surveillance. The integration of large quantities of industrially controlled equipment will be important. Much of the controls will be in common with LEP so a seamless integration of LHC and LEP controls will be sought. A very large amount of new high-tech equipment will have to be tested, assembled and installed in the LEP tunnel in a short time. The manpower and cost constrains will be much tighter than previously. New approaches will have to be found to solve many of these problems, with the additional constraint of integrating them into an existing frame work. (author)

Premiers résultats en provenance du LEP2

CERN Multimedia

CERN Press Office. Geneva

1996-01-01

CERN's Large Electron-Positron collider, LEP, produced its first pair of fundamental particles known as W+ and W- today, taking particle physics research into new and unexplored territory. This follows a busy winter of upgrades which have transformed LEP into a new accelerator, earning it the name LEP2. Hundreds of physicists from all over the world come to CERN to do their research at LEP2, which will be further upgraded over the coming years, bringing the possibility of new discoveries and extending our understanding of the Universe.

LEP dominates LP-HEP

Energy Technology Data Exchange (ETDEWEB)

Fraser, Gordon

1991-09-15

CERN's LEP electron-positron collider was the star of this year's major physics meeting - the Joint International Lepton-Photon Symposium and Europhysics Conference on High Energy Physics (LP-HEP) - held in Geneva from 25 July - 1 August.

CERN moves into the LHC era

CERN Multimedia

2001-01-01

Dr Hans Eschelbacher (on the left), President of the CERN Council for the last three years, hands over to his successor Maurice Bourquin.  The CERN Council, where the representatives of the 20 Member States of the Organization decide on scientific programmes and financial resources, held its 116th session on 15 December under the chairmanship of Dr. Hans C. Eschelbacher (DE). 'Le Roi est mort. Vive le Roi !' The Large Electron Positron Collider (LEP) era has ended and CERN's future is the Large Hadron Collider (LHC), stated Director General, Prof. Luciano Maiani. He opened his report to Council with a 'homage to LEP', which reached the end of its career during 2000 and is now being dismantled to make way for CERN's next major machine, the LHC collider, in the same 27-kilometre tunnel. The strong indications of a Higgs boson at 115 GeV found during the year were the culmination of LEP's long and distinguished physics career, during which the machine opened up new regimes of precision physics, involvi...

Radiation problems in the design of the large electron-positron collider (LEP)

International Nuclear Information System (INIS)

Fasso, A.; Goebel, K.; Hoefert, M.; Rau, G.; Schoenbacher, H.; Stevenson, G.R.; Sullivan, A.H.; Swanson, W.P.; Tuyn, J.W.N.

1984-01-01

This is a comprehensive review of the radiation problems taken into account in the design studies for the Large Electron-Positron collider (LEP) now under construction at CERN. It provides estimates and calculations of the magnitude of the most important hazards, including those from non-ionizing radiations and magnetic fields as well as from ionizing radiation, and describes the measures to be taken in the design, construction, and operation to limit them. Damage to components is considered as well as the risk to people. More general explanations are given of the physical processes and technical parameters that influence the production and effects of radiation, and a comprehensive bibliography provides access to the basic theories and other discussions of the subject. The report effectively summarizes the findings of the Working Group on LEP radiation problems and parallels the results of analogous studies made for the previous large accelerator. The concluding chapters describe the LEP radiation protection system, which is foreseen to reduce doses far below the legal limits for all those working with the machine or living nearby, and summarize the environmental impact. Costs are also briefly considered. (orig.)

LEP dominates LP-HEP

International Nuclear Information System (INIS)

Fraser, Gordon

1991-01-01

CERN's LEP electron-positron collider was the star of this year's major physics meeting - the Joint International Lepton-Photon Symposium and Europhysics Conference on High Energy Physics (LP-HEP) - held in Geneva from 25 July - 1 August

A look at LEP

International Nuclear Information System (INIS)

Anon.

1986-01-01

While work on the tunnel linking England and France under the English Channel has not yet begun, the 26.6 kilometre ring being built at CERN for the LEP electron-positron collider is one of Europe's major engineering projects. (orig./HSI).

Components for the CERN LEP ring

Energy Technology Data Exchange (ETDEWEB)

1987-01-01

One of the most important experimental setups at the LEP (Large Electron Positron Collider) ring is called OPAL (Omni Purpose Apparatus for LEP). Sulzer-Escher Wyss, Zurich, is to deliver the iron yoke, i.e. the mechanical part of one of the nine OPAL detectors. The contract for the yoke includes essentially the two side parts, each consisting of ten modules and two end caps, the middle part, four special modules and two supporting rings, as well as both the poles. The combined weight of all the supply items comes to some 2300 t. (Auth.).

LEP superconducting cavities go into storage

CERN Multimedia

Patrice Loïez

2001-01-01

Superconducting radio-frequency cavities from the LEP-2 phase (1996-2000) are put into storage in the tunnel that once housed the Intersecting Storage Rings (ISR), the world’s first proton collider, located at CERN.

LEP superconducting accelerating cavity module

CERN Multimedia

1995-01-01

With its 27-kilometre circumference, the Large Electron-Positron (LEP) collider was the largest electron-positron accelerator ever built. The excavation of the LEP tunnel was Europe’s largest civil-engineering project prior to the Channel Tunnel. Three tunnel-boring machines started excavating the tunnel in February 1985 and the ring was completed three years later. In its first phase of operation, LEP consisted of 5176 magnets and 128 accelerating cavities. CERN’s accelerator complex provided the particles and four enormous detectors, ALEPH, DELPHI, L3 and OPAL, observed the collisions. LEP was commissioned in July 1989 and the first beam circulated in the collider on 14 July. The collider's initial energy was chosen to be around 91 GeV, so that Z bosons could be produced. The Z boson and its charged partner the W boson, both discovered at CERN in 1983, are responsible for the weak force, which drives the Sun, for example. Observing the creation and decay of the short-lived Z boson was a critical test of...

Physics at LEP

International Nuclear Information System (INIS)

Ellis, J.; Peccei, R.

1986-01-01

This report surveys physics which may be investigated at LEP, the Large Electron-Positron collider under construction at CERN. Five general areas are emphasized, namely: precision measurements at the Z 0 peak; studies of toponium; searches for possible new particles; QCD, γγ, and heavy quark studies; and experiments at the highest LEP energies up to and beyond the W + W - pair-production threshold. Wherever possible, full cross section formulae are given, together with references to the original literature where more details may be found. (orig.)

Quark radiation from LEP

Energy Technology Data Exchange (ETDEWEB)

Cartwright, Susan

1992-04-15

Like any other electrically charged particles, quarks should give out electromagnetic radiation (photons) when they vibrate. One of the physics results from CERN's LEP collider is the first clear observation of this quark radiation from electron-positron collisions. At lower energies this radiation could only be inferred.

Quark radiation from LEP

International Nuclear Information System (INIS)

Cartwright, Susan

1992-01-01

Like any other electrically charged particles, quarks should give out electromagnetic radiation (photons) when they vibrate. One of the physics results from CERN's LEP collider is the first clear observation of this quark radiation from electron-positron collisions. At lower energies this radiation could only be inferred

Radiation protection considerations in the design of the LHC, CERN's large hadron collider

International Nuclear Information System (INIS)

Hoefert, M.; Huhtinen, M.; Moritz, L.E.; Nakashima, H.; Potter, K.M.; Rollet, S.; Stevenson, G.R.; Zazula, J.M.

1996-01-01

This paper describes the radiological concerns which are being taken into account in the design of the LHC (CERN's future Large Hadron Collider). The machine will be built in the 27 km circumference ring tunnel of the existing LEP collider at CERN. The high intensity of the circulating beams (each containing more than 10 14 protons at 7 TeV) determines the thickness specification of the shielding of the main-ring tunnel, the precautions to be taken in the design of the beam dumps and their associated caverns and the radioactivity induced by the loss of protons in the main ring by inelastic beam-gas interactions. The high luminosity of the collider is designed to provide inelastic collision rates of 10 9 per second in each of the two principal detector installations, ATLAS and CMS. These collisions determine the shielding of the experimental areas, the radioactivity induced in both the detectors and in the machine components on either side of the experimental installations and, to some extent, the radioactivity induced in the beam-cleaning (scraper) systems. Some of the environmental issues raised by the project will be discussed. (author)

From the CERN web: Collide@CERN, Fermilab neutrinos and more

CERN Multimedia

2015-01-01

This new section highlights articles, blog posts and press releases published in the CERN web environment over the past weeks. This way, you won’t miss a thing...   Ruth Jarman and Joe Gerhardt. (Photo: Matthias H. Risse). Collide@CERN Ars Electronica Award goes to “Semiconductor” 10 August – Collide@CERN Ruth Jarman and Joe Gerhardt, two English artists collaborating under the name Semiconductor, are this year’s recipients of the Collide@CERN Ars Electronica Award. In the coming months, they will begin a two-month residency at CERN.  Continue to read…     Illustration: Fermilab/Sandbox Studio.   Fermilab experiment sees neutrinos change over 500 miles 7 August - Fermilab press release Scientists on the NOvA experiment saw their first evidence of oscillating neutrinos, confirming that the extraordinary detector built for the project not only functions as planned but is also making great p...

Collide@CERN ProHelvetia Public Lecture

CERN Multimedia

CERN. Geneva; Heuer, Rolf; Mr. de Diesbach, Simon; Mr. Dubois, Marc; Ms. Perrenoud, Laura; Mr. Vust, Michel; Mrs. Bello, Monica

2015-01-01

You are very warmly invited to the opening presentation of Fragment.In’s residency at CERN. Fragment.In are the winners of Collide@CERN ProHelvetia, a collective formed by Laura Perrenoud, Simon de Diesbach, and Marc Dubois. They will present their artistic work along with their CERN scientific inspiration partner, who will present his/her work on Science. In their proposal, Fragment.In has a unique, original and creative approach to data visualization. We look forward to having them at CERN. Collide@CERN is the three month residency programme providing artists with time and space to reflect, research and renew their artistic practice.

CERN: Making CLIC tick

International Nuclear Information System (INIS)

Anon.

1990-01-01

While the Large Hadron Collider (LHC) scheme for counter-rotating proton beams in a new superconducting ring to be built in CERN's existing 27-kilometre LEP tunnel is being pushed as the Laboratory's main construction project for the 1990s, research and development continues in parallel for an eventual complementary attack on new physics frontiers with CERN's Linear Collider - CLIC - firing TeV electron and positron beams at each other

Superconducting linear colliders

International Nuclear Information System (INIS)

Anon.

1990-01-01

The advantages of superconducting radiofrequency (SRF) for particle accelerators have been demonstrated by successful operation of systems in the TRISTAN and LEP electron-positron collider rings respectively at the Japanese KEK Laboratory and at CERN. If performance continues to improve and costs can be lowered, this would open an attractive option for a high luminosity TeV (1000 GeV) linear collider

CERN-Fermilab Hadron Collider Physics Summer School

CERN Multimedia

2007-01-01

Applications are now open for the 2nd CERN-Fermilab Hadron Collider Physics Summer School, which will take place at CERN from 6 to 15 June 2007. The school web site is http://cern.ch/hcpss with links to the academic program and application procedure. The application deadline is 9 March 2007. The results of the selection process will be announced shortly thereafter. The goal of the CERN-Fermilab Hadron Collider Physics Summer Schools is to offer students and young researchers in high energy physics a concentrated syllabus on the theory and experimental challenges of hadron collider physics. The first school in the series, held last summer at Fermilab, covered extensively the physics at the Tevatron collider experiments. The second school to be held at CERN, will focus on the technology and physics of the LHC experiments. Emphasis will be given on the first years of data-taking at the LHC and on the discovery potential of the programme. The series of lectures will be  supported by in-depth discussion sess...

CERN Library | Mario Campanelli presents "Inside CERN's Large Hadron Collider" | 16 March

CERN Multimedia

CERN Library

2016-01-01

"Inside CERN's Large Hadron Collider" by Mario Campanelli. Presentation on Wednesday, 16 March at 4 p.m. in the Library (bldg 52-1-052) The book aims to explain the historical development of particle physics, with special emphasis on CERN and collider physics. It describes in detail the LHC accelerator and its detectors, describing the science involved as well as the sociology of big collaborations, culminating with the discovery of the Higgs boson.  Inside CERN's Large Hadron Collider  Mario Campanelli World Scientific Publishing, 2015  ISBN 9789814656641​

PARTICLE PHYSICS: CERN Gives Higgs Hunters Extra Month to Collect Data.

Science.gov (United States)

Morton, O

2000-09-22

After 11 years of banging electrons and positrons together at higher energies than any other machine in the world, CERN, the European laboratory for particle physics, had decided to shut down the Large Electron-Positron collider (LEP) and install a new machine, the Large Hadron Collider (LHC), in its 27-kilometer tunnel. In 2005, the LHC will start bashing protons together at even higher energies. But tantalizing hints of a long-sought fundamental particle have forced CERN managers to grant LEP a month's reprieve.

The LEP e+e−ring at the energy frontier of circular lepton colliders

CERN Document Server

Hofmann, Albert

2016-01-01

The Large Electron Positron ring (LEP) was a circular lepton collider at CERN. It operated at beam energies around 47GeV to produce the neutral Z0 particle and above 80 GeV to create pairs of the charged W± bosons. At these high energies the emission of synchrotron radiation was important and demanded a very high voltage of the RF-system. It also influenced the choice of many other machine parameters. This presentation tries to show how the basic accelerator physics was used to optimize the machine and to find innovative solutions for some problems: magnets with concrete between the laminations, modulated cavities, Nb-Cu superconducting cavities, nonevaporable getter pumps, optics analysis from multi-turn data and many more.

CERN balances linear collider studies

CERN Multimedia

ILC Newsline

2011-01-01

The forces behind the two most mature proposals for a next-generation collider, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC) study, have been steadily coming together, with scientists from both communities sharing ideas and information across the technology divide. In a support of cooperation between the two, CERN in Switzerland, where most CLIC research takes place, recently converted the project-specific position of CLIC Study Leader to the concept-based Linear Collider Study Leader.   The scientist who now holds this position, Steinar Stapnes, is charged with making the linear collider a viable option for CERN’s future, one that could include either CLIC or the ILC. The transition to more involve the ILC must be gradual, he said, and the redefinition of his post is a good start. Though not very much involved with superconducting radiofrequency (SRF) technology, where ILC researchers have made significant advances, CERN participates in many aspect...

The LEP project

International Nuclear Information System (INIS)

Anon.

1980-01-01

At its 64th Session on 19-20 December, the CERN Council received a document from its Scientific Policy Committee entitled 'Proposal for the next major accelerator project at CERN'. Following the studies which have been carried out over the past few years, the SPC recommended that the 'Design Study of a 22 to 130 GeV electronpositron colliding beam machine (LEP)' should be used as the basis for planning the next accelerator for CERN and recommended that the accelerator should be built adjacent to the existing Laboratory.These recommendations were mostly favourably received by the delegates of the CERN Member States and the stage seems set for the formal presentation of the project in June of this year

Collide@CERN: Horizons Irrésolus

CERN Multimedia

2016-01-01

Sound Installation by Collide@CERN Geneva artists Rudy Decelière and Vincent Hänni in collaboration with physicists Diego Blas and Robert Kieffer, for the Electron Festival 25-27th March, 2016 (see here).   Horizons irrésolus is a sound installation that follows on the artistic residency Collide@CERN 2014.    Registration is absolutely required. Each guest will have to have registered using their own name. Guests without having registered will not be able to come into CERN. Free entrance: Book here  A shuttle will be available every 15 minutes from 6 p.m. until 9 p.m. from CERN Reception (in front of CERN Globe) to the sound art installation. Access from Geneva to CERN Reception by tram 18, end of the line. With the support from The Republic and Canton of Geneva and The City of Geneva. Find out more on the artists and their Geneva 2...

CERN Jackfest

Energy Technology Data Exchange (ETDEWEB)

Anon.

1986-07-15

Over four decades, from his initial investigations which helped open up meson physics at the end of the 1940s to leadership of one of the big experiments being prepared or CERN's LEP electron-positron Collider, the career of Jack Steinberger has paced the development of particle physics.

The DELPHI experiment at LEP

International Nuclear Information System (INIS)

Alekseev, G.D.; Bardin, D. Yu.; Bilen'kij, M.S.

2000-01-01

This paper summarizes the current status of the DELPHI experiment, which is operating at the Large Electron Positron (LEP) Collider at CERN. The results from running at the energies around the Z resonance (LEP1) are based on the full available data, while the results obtained at higher energies (LEP2) are based on the data collected up to 1998. The analysis of the data collected at the highest centre-of-mass energies (above 200 GeV) is still in progress and new results are expected. We present briefly some of the most important DELPHI results paying a special attention to the contribution of JINR group to the detector construction and data analysis

LEP copper accelerating cavities

CERN Multimedia

Laurent Guiraud

1999-01-01

These copper cavities were used to generate the radio frequency electric field that was used to accelerate electrons and positrons around the 27-km Large Electron-Positron (LEP) collider at CERN, which ran from 1989 to 2000. The copper cavities were gradually replaced from 1996 with new superconducting cavities allowing the collision energy to rise from 90 GeV to 200 GeV by mid-1999.

CERN Jackfest

International Nuclear Information System (INIS)

Anon.

1986-01-01

Over four decades, from his initial investigations which helped open up meson physics at the end of the 1940s to leadership of one of the big experiments being prepared or CERN's LEP electron-positron Collider, the career of Jack Steinberger has paced the development of particle physics

Une énergie record ouvre de nouvelles perspectives de découvertes au LEP

CERN Document Server

CERN Press Office. Geneva

1999-01-01

At CERN on 2 August 1999 at 11h15, beams of electrons and positrons were accelerated in the Large Electron Positron Collider (LEP) to 100 GeV and brought into collision for the first time at this energy. There were two reasons for the backslapping, cheering and popping of corks that followed in the LEP control room. First, the setting of a new energy record for an electron-positron accelerator, represents a tremendous technical achievement by CERN accelerator specialists. Second, the collision energy of 200 GeV opens up exciting new discovery potential for the LEP experiments.

Advanced Superconducting Technology for Global Science The Large Hadron Collider at CERN

CERN Document Server

Lebrun, P

2002-01-01

The Large Hadron Collider (LHC), presently in construction at CERN, the European Organisation for Nuclear Research near Geneva (Switzerland), will be, upon its completion in 2005 and for the next twenty years, the most advanced research instrument of the world's high-energy physics community, providing access to the energy frontier above 1 TeV per elementary constituent. Re-using the 26.7-km circumference tunnel and infrastructure of the past LEP electron-positon collider, operated until 2000, the LHC will make use of advanced superconducting technology - high-field Nb-Ti superconducting magnets operated in superfluid helium and a cryogenic ultra-high vacuum system - to bring into collision intense beams of protons and ions at unprecedented values of center-of-mass energy and luminosity (14 TeV and 1034 cm-2.s-1, respectively with protons). After some ten years of focussed R&D, the LHC components are presently series-built in industry and procured through world-wide collaboration. After briefly recalling ...

The LEP impedance model

Energy Technology Data Exchange (ETDEWEB)

Zotter, B [European Organization for Nuclear Research, Geneva (Switzerland)

1996-08-01

This report describes a number of measurements and computations of the impedance of the Large Electron Positron collider LEP at CERN. The work has been performed over several years, together with D. Brandt, K. Cornelis, A. Hofmann, G. Sabbi and many others. The agreement between measurements of single bunch instabilities on the machine and computer simulations is in general excellent and gives confidence in the impedance model used. (author)

People and things. CERN Courier, May 1985, v. 25(4)

Energy Technology Data Exchange (ETDEWEB)

Anon.

1985-05-15

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events. A workshop is being arranged to discuss the potential of the CERN SPS proton-antiproton Collider for the early 90s in view of the then simultaneous operation of the Tevatron at Fermilab, LEP at CERN and HERA at DESY, and to evaluate the need for a new Collider detector.

2nd CERN-Fermilab Hadron Collider Physics Summer School

CERN Document Server

Gian Giudice; Ellis, Nick; Jakobs, Karl; Mage, Patricia; Seymour, Michael H; Spiropulu, Maria; Wilkinson, Guy; CERN-FNAL Summer School; Hadron Collider Physics Summer School

2007-01-01

For the past few years, experiments at the Fermilab Tevatron Collider have once again been exploring uncharted territory at the current energy frontier of particle physics. With CERN's LHC operations to start in 2007, a new era in the exploration of the fundamental laws of nature will begin. In anticipation of this era of discovery, Fermilab and CERN are jointly organizing a series of "Hadron Collider Physics Summer Schools", whose main goal is to offer a complete picture of both the theoretical and experimental aspects of hadron collider physics. Preparing young researchers to tackle the current and anticipated challenges at hadron colliders, and spreading the global knowledge required for a timely and competent exploitation of the LHC physics potential, are concerns equally shared by CERN, the LHC host laboratory, and by Fermilab, the home of the Tevatron and host of CMS's LHC Physics Center in the U.S. The CERN-Fermilab Hadron Collider Physics Summer School is targeted particularly at young postdocs in exp...

12th CERN-Fermilab Hadron Collider Physics Summer School

CERN Document Server

2017-01-01

CERN and Fermilab are jointly offering a series of "Hadron Collider Physics Summer Schools", to prepare young researchers for these exciting times. The school has alternated between CERN and Fermilab, and will return to CERN for the twelfth edition, from 28th August to 6th September 2017. The CERN-Fermilab Hadron Collider Physics Summer School is an advanced school targeted particularly at young postdocs and senior PhD students working towards the completion of their thesis project, in both Experimental High Energy Physics (HEP) and phenomenology. Other schools, such as the CERN European School of High Energy Physics, may provide more appropriate training for students in experimental HEP who are still working towards their PhDs. Mark your calendar for 28 August - 6 September 2017, when CERN will welcome students to the twelfth CERN-Fermilab Hadron Collider Physics Summer School. The School will include nine days of lectures and discussions, and one free day in the middle of the period. Limited scholarship ...

Arrêt du L.E.P annoncé au CERN

CERN Multimedia

Causse, M

2000-01-01

Ruining the hopes of researchers that they might soon make an incredible discovery, the director of CERN has announced the closure of LEP at the end of the year and acceleration of the construction of the LHC (1/2 page).

LEP shuts down after eleven years of forefront research

CERN Multimedia

2000-01-01

After extended consultation with the appropriate scientific committees, CERN’s Director-General Luciano Maiani announced today that the LEP accelerator had been switched off for the last time. LEP was scheduled to close at the end of September 2000 but tantalising signs of possible new physics led to LEP’s run being extended until 2 November. At the end of this extra period, the four LEP experiments had produced a number of collisions compatible with the production of Higgs particles with a mass of around 115 GeV. These events were also compatible with other known processes. The new data was not sufficiently conclusive to justify running LEP in 2001, which would have inevitable impact on LHC construction and CERN’s scientific programme. The CERN Management decided that the best policy for the Laboratory is to proceed full-speed ahead with the Large Hadron Collider (LHC) project. Steve Myers, Head of SL Division, with members of the LEP team, pulling the symbolic rope to swich off the accelerator. CERN Co...

The LHC road at CERN

International Nuclear Information System (INIS)

Anon.

1989-01-01

To explore the 1 TeV energy scale where fundamental particle interactions should encounter new conditions, two major routes were proposed - a high magnetic field proton collider in the LEP tunnel, dubbed LHC for Large Hadron Collider, and the CERN Linear Collider (CLIC) to supply beams of electrons and positrons. Exploratory studies have shown that while CLIC remains a valid long-term goal, LHC appears as the most cost-effective way for CERN to enter the 1 TeV arena. High-field superconducting magnet prototype work demonstrates that a 'two-in-one' design supplying the 10 tesla fields needed to handle LHC's 8 TeV proton beams (collision energy 16 TeV) is a practical proposition. (orig./HSI).

Collide@CERN - public lecture

CERN Multimedia

2012-01-01

CERN, the Republic and Canton of Geneva and the City of Geneva are delighted to invite you to a public lecture by Gilles Jobin, first winner of the Collide@CERN Geneva Dance and Performance Artist-in-residence Prize, and his CERN inspiration partner, Joao Pequenao. They will present their work in dance and science at the Globe of Science and Innovation on Wednesday, 23 May 2012 at 7 p.m. (doors open at 6.30 p.m.).   
                                                  Programme 19:00 Opening address by - Professor Rolf-Dieter Heuer, CERN Director-General, - Ariane Koek...

CERN: New cooperation agreement with China

International Nuclear Information System (INIS)

Anon.

1992-01-01

As preparations gather momentum for its LHC proton collider to be built in the 27-kilometre LEP tunnel, CERN is encouraging increased international involvement in the project, both for the machine itself and for the experiments which will use it

Art and science interactions - First Collide @CERN public lecture by Julius Von Bismarck

CERN Multimedia

CERN. Geneva

2012-01-01

Creative collisions between the arts and science have begun at CERN with the first Collide@CERN artist, Julius Von Bismarck starting his digital arts residency at the world's largest particle physics laboratory outside Geneva. He was chosen from 395 entries from 40 countries around the world from the Prix Ars Electronica Collide@CERN competition launched last September 2011. To mark this special occasion, the first Collide@CERN public lecture open to everyone will take place on March 21st 2012 at CERN's Globe of Science and Innovation, with a drinks reception at 18.45 and with presentations starting at 19.30. The event is free and will be opened by the Director General of CERN, Professor Rolf-Dieter Heuer and Gerfried Stocker, the Artistic Director of Ars Electronica, Linz, - CERN's international cultural partners for the digital arts Collide@CERN award known as Prix Ars Electronica Collide@CERN in recognition of our joint partnership. Julius Von Bismarck and his CERN science inspiration partner, the physic...

Performance of the upgraded small angle tile calorimeter at LEP

CERN Document Server

Alvsvaag, S J; Barreira, G; Benvenuti, Alberto C; Bigi, M; Bonesini, M; Bozzo, M; Camporesi, T; Carling, H; Cassio, V; Castellani, L; Cereseto, R; Chignoli, F; Della Ricca, G; Dharmasiri, D R; Espirito-Santo, M C; Falk, E; Fenyuk, A; Ferrari, P; Gamba, D; Giordano, V; Guz, Yu; Guerzoni, M; Gumenyuk, S A; Hedberg, V; Jarlskog, G; Karyukhin, A N; Klovning, A; Konoplyannikov, A K; Kronkvist, I J; Lanceri, L; Leoni, R; Maeland, O A; Maio, A; Mazza, R; Migliore, E; Navarria, Francesco Luigi; Nossum, B; Obraztsov, V F; Onofre, A; Paganoni, M; Pegoraro, M; Peralta, L; Petrovykh, L P; Pimenta, M; Poropat, P; Prest, M; Read, A L; Romero, A; Shalanda, N A; Simonetti, L; Skaali, T B; Stugu, B; Terranova, F; Tomé, B; Torassa, E; Trapani, P P; Verardi, M G; Vallazza, E; Vlasov, E; Zaitsev, A

1998-01-01

The small angle tile calorimeter (STIC) provides calorimetric coverage in the very forward region of the DELPHI experiment at the CERN LEP collider. The structure of the calorimeters, built with so- called "shashlik" technique, $9 allows the insertion of tracking detectors within the sampling structure, in order to make it possible to determine the direction of the showering particle. Presented here are some results demonstrating the performance of the $9 calorimeter and of these tracking detectors at LEP. (5 refs).

Le CERN s'envole vers des énergies plus élevées

CERN Multimedia

CERN Press Office. Geneva

1995-01-01

CERN's Large Electron-Positron Collider LEP has moved up a gear. On 31 October, particle collisions were observed for the first time at 130 GeV, the highest energy ever achieved in an electron-positron collider. After six years of studying the elementa ry particle known as the Z, LEP moved smoothly up to its new energy, bringing the possibility of discovering new particles and furthering our understanding of how the Universe works.

CERN-Fermilab Hadron Collider Physics Summer School 2013 open for applications

CERN Multimedia

2013-01-01

Mark your calendar for 28 August - 6 September 2013, when CERN will welcome students to the eighth CERN-Fermilab Hadron Collider Physics Summer School.   Experiments at hadron colliders will continue to provide our best tools for exploring physics at the TeV scale for some time. With the completion of the 7-8 TeV runs of the LHC, and the final results from the full Tevatron data sample becoming available, a new era in particle physics is beginning, heralded by the Higgs-like particle recently discovered at 125 GeV. To realize the full potential of these developments, CERN and Fermilab are jointly offering a series of "Hadron Collider Physics Summer Schools", to prepare young researchers for these exciting times. The school has alternated between CERN and Fermilab, and will return to CERN for the eighth edition, from 28 August to 6 September 2013. The CERN-Fermilab Hadron Collider Physics Summer School is an advanced school which particularly targets young postdocs in exper...

Comedy Collider presents: No cause for conCERN

CERN Multimedia

Traczyk, Piotr

2014-01-01

Comedy Collider presents: No cause for conCERN was the highly anticipated follow up to LHComedy: CERN After Dark, starring an entirely new ensemble of comedy talent. Time: 13th June 2014, 19:30 for 20:00 Location: Globe of Science and Innovation, CERN, Geneva, Switzerland

At work on LEP, the world’s most powerful electron–positron collider

CERN Document Server

Patrice Loiez,

1999-01-01

The LHC will be built inside the same tunnel as an existing accelerator, the Large Electron Positron (LEP) collider which came on stream in 1989. LEP will be removed from the tunnel at the end of this year to make way for the LHC. Here technicians make delicate adjustments to one of LEP’s thousands of magnets.

Ryoji Ikeda, Data Artist - Prix Ars Electronica Collide@CERN

CERN Multimedia

CERN. Geneva; Koek, Ariane; Heuer, Rolf; Ikeda, Ryoji; Mr. Horst, Hoertner

2014-01-01

at the CERN Globe of Science and Innovation, CERN. You are very warmly invited to the opening presentation of Data Artist, Ryoji Ikeda’s residency at CERN. Ryoji Ikeda, one of the world’s leading electronic composers and visual artists, is the new Prix Ars Electronica Collide@CERN award winner. Ryoji Ikeda and his science inspiration partner, Theoretical Physicist, Dr. Tom Melia will talk about their work in arts and science. They are at the beginning of their creative journey together at CERN. A little about Ryoji Ikeda – the new Prix Ars Electronica Collide@CERN artist in residence. Ryoji Ikeda focuses on the essential characteristics of sound itself and that of visuals as light by means of both mathematical precision and mathematical aesthetics. Ikeda has gained a reputation as one of the few international artists working convincingly across both visual ...

2nd CERN-Fermilab Hadron Collider Physics Summer School

CERN Document Server

2007-01-01

June 6-15, 2007, CERN The school web site is http://cern.ch/hcpss with links to the academic programme and the application procedure. The APPLICATION DEADLINE IS 9 MARCH 2007 The results of the selection process will be announced shortly thereafter. The goal of the CERN-Fermilab Hadron Collider Physics Summer Schools is to offer students and young researchers in high energy physics a concentrated syllabus on the theory and experimental challenges of hadron collider physics. The first school in the series, held last summer at Fermilab, extensively covered the physics at the Tevatron collider experiments. The second school, to be held at CERN, will focus on the technology and physics of the LHC experiments. Emphasis will be placed on the first years of data-taking at the LHC and on the discovery potential of the programme. The series of lectures will be supported by in-depth discussion sessions and will include the theory and phenomenology of hadron collisions, discovery physics topics, detector and analysis t...

The long-term performance of the S-band klystron modulator system in the CERN LEP pre-injector

CERN Document Server

McMonagle, G; Rossat, G

2000-01-01

The Large Electron-Positron collider (LEP) is the final machine in a chain of four accelerators that are used to create particle collisions for high-energy physics experiments. LEP collides bunches of electrons (e/sup -/) with bunches of positrons (e/sup +/) that have originated in the LEP Injector Linac (LIL). These particles travel around the 27 km circumference of the LEP ring in opposite directions at velocities close to the speed of light. When bunches of particles collide, bursts of very high energy are created during a tiny fraction of a second, emulating the state of the early Universe. Four huge detector assemblies record the tracks of particles created in this way, and provide the physicists with a means of looking at the behaviour of matter at these high energies. LIL is at the front end of this chain and is used to produce the sequence of e/sup -/ and e/sup +/ beam pulses that are accumulated in 4 or 8 bunches, at a 100 Hz rate, in the Electron Positron Accumulator (EPA). The klystron- modulators,...

Advanced superconducting technology for global science: The Large Hadron Collider at CERN

Science.gov (United States)

Lebrun, Ph.

2002-05-01

The Large Hadron Collider (LHC), presently in construction at CERN, the European Organization for Nuclear Research near Geneva (Switzerland), will be, upon its completion in 2005 and for the next twenty years, the most advanced research instrument of the world's high-energy physics community, providing access to the energy frontier above 1 TeV per elementary constituent. Re-using the 26.7-km circumference tunnel and infrastructure of the past LEP electron-positon collider, operated until 2000, the LHC will make use of advanced superconducting technology-high-field Nb-Ti superconducting magnets operated in superfluid helium and a cryogenic ultra-high vacuum system-to bring into collision intense beams of protons and ions at unprecedented values of center-of-mass energy and luminosity (14 TeV and 1034 cm-2ṡs-1, respectively with protons). After some ten years of focussed R&D, the LHC components are presently series-built in industry and procured through world-wide collaboration. After briefly recalling the physics goals, performance challenges and design choices of the machine, we describe its major technical systems, with particular emphasis on relevant advances in the key technologies of superconductivity and cryogenics, and report on its construction progress.

Collide@CERN: sharing inspiration

CERN Multimedia

Katarina Anthony

2012-01-01

Late last year, Julius von Bismarck was appointed to be CERN's first "artist in residence" after winning the Collide@CERN Digital Arts award. He’ll be spending two months at CERN starting this March but, to get a flavour of what’s in store, he visited the Organization last week for a crash course in its inspiring activities.   Julius von Bismarck, taking a closer look... When we arrive to interview German artist Julius von Bismarck, he’s being given a presentation about antiprotons’ ability to kill cancer cells. The whiteboard in the room contains graphs and equations that might easily send a non-scientist running, yet as Julius puts it, “if I weren’t interested, I’d be asleep”. Given his numerous questions, he must have been fascinated. “This ‘introduction’ week has been exhilarating,” says Julius. “I’ve been able to interact ...

Shimon Pérès visite le CERN

CERN Multimedia

CERN Press Office. Geneva

1995-01-01

Shimon Peres, Israel's Foreign Minister, made an official visit to CERN on 26 January. He was accompanied by the Israeli Ambassador to the International Organizations in Geneva, Yosef Lamdan, and was received by CERN's Director General, Prof. Christopher Llewellyn Smith. The visit took place at the site of the giant OPAL experiment, on the Large Electron Positron Collider (LEP), where there is major Israeli involvement.

Fermilab Tevatron and CERN LEP II probes of minimal and string-motivated supergravity models

International Nuclear Information System (INIS)

Baer, H.; Gunion, J.F.; Kao, C.; Pois, H.

1995-01-01

We explore the ability of the Fermilab Tevatron to probe minimal supersymmetry with high-energy-scale boundary conditions motivated by supersymmetry breaking in the context of minimal and string-motivated supergravity theory. A number of boundary condition possibilities are considered: dilatonlike string boundary conditions applied at the standard GUT unification scale or alternatively at the string scale; and extreme (''no-scale'') minimal supergravity boundary conditions imposed at the GUT scale or string scale. For numerous specific cases within each scenario the sparticle spectra are computed and then fed into ISAGET 7.07 so that explicit signatures can be examined in detail. We find that, for some of the boundary condition choices, large regions of parameter space can be explored via same-sign dilepton and isolated trilepton signals. For other choices, the mass reach of Tevatron collider experiments is much more limited. We also compare the mass reach of Tevatron experiments with the corresponding reach at CERN LEP 200

Hunt for Higgs particle wins time for CERN collider

CERN Multimedia

Abbott, A

2000-01-01

Physicists at CERN believe that a new analysis of their recent data indicates it is possible they have witnessed the creation of the Higgs boson. As a result the director general has agreed to extend the operation of LEP by one more month (1/2 page).

2nd CERN-Fermilab Hadron Collider Physics Summer School, June 6-15, 2007, CERN

CERN Multimedia

2007-01-01

The school web site is http://cern.ch/hcpss with links to the academic programme and the application procedure. The APPLICATION DEADLINE IS 9 MARCH 2007. The results of the selection process will be announced shortly thereafter. The goal of the CERN-Fermilab Hadron Collider Physics Summer Schools is to offer students and young researchers in high energy physics a concentrated syllabus on the theory and experimental challenges of hadron collider physics. The first school in the series, held last summer at Fermilab, covered extensively the physics at the Tevatron collider experiments. The second school, to be held at CERN, will focus on the technology and physics of the LHC experiments. Emphasis will be placed on the first years of data-taking at the LHC and on the discovery potential of the programme. The series of lectures will be supported by in-depth discussion sessions and will include the theory and phenomenology of hadron collisions, discovery physics topics, detector and analysis techniques and tools...

CERN's Large Hadron Collider project

Science.gov (United States)

Fearnley, Tom A.

1997-03-01

The paper gives a brief overview of CERN's Large Hadron Collider (LHC) project. After an outline of the physics motivation, we describe the LHC machine, interaction rates, experimental challenges, and some important physics channels to be studied. Finally we discuss the four experiments planned at the LHC: ATLAS, CMS, ALICE and LHC-B.

CERN's Large Hadron Collider project

International Nuclear Information System (INIS)

Fearnley, Tom A.

1997-01-01

The paper gives a brief overview of CERN's Large Hadron Collider (LHC) project. After an outline of the physics motivation, we describe the LHC machine, interaction rates, experimental challenges, and some important physics channels to be studied. Finally we discuss the four experiments planned at the LHC: ATLAS, CMS, ALICE and LHC-B

LEP for twice the energy

Energy Technology Data Exchange (ETDEWEB)

Anon.

1993-01-15

In 1995, CERN's 27-kilometre LEP electron-positron collider should start operating for physics at considerably higher energy. Since its commissioning in 1989, the machine has been operating around 45.5 GeV per beam to give collision energies that home in on the Z particle - the electrically neutral carrier of the weak nuclear force, with a mass of 91 GeV. The Z, discovered at CERN in 1983 by Carlo Rubbia's UA1 protonantiproton tour de force, was for a long time a rare physics jewel. Until LEP came along, only a handful had been seen. With millions now captured by the four LEP experiments - Aleph, Delphi, L3 and Opal - the Z has become everyday physics, and the accumulated precision Z data give an incisive view inside today's Standard Model. The self-consistency of these measurements make physicists confident that the sixth ('top') quark should turn up around 150 GeV. But the Z is only one side of the picture. For the self-consistency of the Standard Model to become really watertight, a precision fix is also needed on the W at 81 GeV, the electrically charged companion of the Z. While the neutral Z can be produced directly in electron-positron annihilations, the charged Ws can only be produced in pairs, hence the call for higher energies at LEP. (The project is known as LEP200, but 200 GeV is acknowledged as an optimistic energy target.) To roughly double beam energy from around 45 GeV for Z physics to the level needed for W production calls for an additional 1900 Megavolts of accelerating voltage.

LEP for twice the energy

International Nuclear Information System (INIS)

Anon.

1993-01-01

In 1995, CERN's 27-kilometre LEP electron-positron collider should start operating for physics at considerably higher energy. Since its commissioning in 1989, the machine has been operating around 45.5 GeV per beam to give collision energies that home in on the Z particle - the electrically neutral carrier of the weak nuclear force, with a mass of 91 GeV. The Z, discovered at CERN in 1983 by Carlo Rubbia's UA1 protonantiproton tour de force, was for a long time a rare physics jewel. Until LEP came along, only a handful had been seen. With millions now captured by the four LEP experiments - Aleph, Delphi, L3 and Opal - the Z has become everyday physics, and the accumulated precision Z data give an incisive view inside today's Standard Model. The self-consistency of these measurements make physicists confident that the sixth ('top') quark should turn up around 150 GeV. But the Z is only one side of the picture. For the self-consistency of the Standard Model to become really watertight, a precision fix is also needed on the W at 81 GeV, the electrically charged companion of the Z. While the neutral Z can be produced directly in electron-positron annihilations, the charged Ws can only be produced in pairs, hence the call for higher energies at LEP. (The project is known as LEP200, but 200 GeV is acknowledged as an optimistic energy target.) To roughly double beam energy from around 45 GeV for Z physics to the level needed for W production calls for an additional 1900 Megavolts of accelerating voltage

CERN-BINP Workshop for Young Scientists in $e^{+}e^{-}$ Colliders

CERN Document Server

Linssen, Lucie; eCOL 2016

2017-01-01

The "CERN-BINP workshop for young scientists in e+e- colliders" is organised in the framework of the EU-funded CREMLIN project. The CREMLIN project aims at strengthening science cooperation between six Russian megascience facilities and related research infrastructure counterparts in Europe. BINP and CERN coordinate a dedicated CREMLIN work package focusing on a future super-charm-tau factory (SCT) at BINP. SCT aims at producing e+e- collisions with up to 5 GeV centre-of-mass energy and at very high luminosity. In parallel CERN is hosting design studies for two possible high-energy e+e- colliders: FCC-ee and CLIC. In matters of physics, design and technologies the BINP and CERN studies address technological and scientific questions of common interest. Similar issues are dealt with in the framework of other flavour factories and energy frontier e+e- colliders worldwide. The 3-day workshop provides young scientists (at the student and postdoc level) opportunities to present their work and exchange experiences. ...

Rock samples from LEP/LHC tunnel excavation

CERN Multimedia

1985-01-01

Rock samples taken from 0 to 170 m below ground on the CERN site when the LEP (Large Electron Positron collider) pit number 6 was drilled in Bois-chatton (Versonnex). The challenges of LHC civil engineering: A mosaic of works, structures and workers of differents crafts and origins. Three consulting consortia for the engineering and the follow-up of the works. Four industrial consortia for doing the job. A young team of 25 CERN staff, 30 surface buildings, 32 caverns of all sizes, 170 000 m3 of concrete, 420 000 m3 excavated. 1998-2004 : six years of work and 340 millions Swiss Francs.

Public Lecture Collide@CERN Pro Helvetia | 23 July | Main Auditorium

CERN Multimedia

2015-01-01

You are very warmly invited to the opening presentation of Fragment.In’s residency at CERN.   Fragment.In: Simon de Diesbach, Laura Perrenoud and Marc Dubois. 23 July 2015 - 7 p.m. Main Auditorium  The lecture will be followed by a drinks reception at 8.30 p.m. Doors open at 6.30 p.m.  Opening address by Rolf Heuer, CERN Director-General, Michel Vust, project leader at the Swiss Arts Council Pro Helvetia, and Monica Bello, Head of Arts@CERN. Fragment.In are the winners of Collide@CERN Pro Helvetia, formed by Laura Perrenoud, Simon de Diesbach, and Marc Dubois. They will present their artistic work along with their CERN scientific inspiration partner, who will present his/her scientific work. In their proposal, Fragment.In took a unique, original and creative approach to data visualization. We look forward to having them at CERN.  Fragment.In Collide@CERN is the three month residency programme providing artists with time and...

Advanced superconducting technology for global science: The Large Hadron Collider at CERN

International Nuclear Information System (INIS)

Lebrun, Ph.

2002-01-01

The Large Hadron Collider (LHC), presently in construction at CERN, the European Organization for Nuclear Research near Geneva (Switzerland), will be, upon its completion in 2005 and for the next twenty years, the most advanced research instrument of the world's high-energy physics community, providing access to the energy frontier above 1 TeV per elementary constituent. Re-using the 26.7-km circumference tunnel and infrastructure of the past LEP electron-positon collider, operated until 2000, the LHC will make use of advanced superconducting technology-high-field Nb-Ti superconducting magnets operated in superfluid helium and a cryogenic ultra-high vacuum system-to bring into collision intense beams of protons and ions at unprecedented values of center-of-mass energy and luminosity (14 TeV and 10 34 cm -2 ·s -1 , respectively with protons). After some ten years of focussed R and D, the LHC components are presently series-built in industry and procured through world-wide collaboration. After briefly recalling the physics goals, performance challenges and design choices of the machine, we describe its major technical systems, with particular emphasis on relevant advances in the key technologies of superconductivity and cryogenics, and report on its construction progress

People and things. CERN Courier, Apr 1986, v. 26(3)

Energy Technology Data Exchange (ETDEWEB)

Anon.

1986-04-15

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events. A Summer Study to be held in Snowmass, Colorado, from 23 June to 11 July will allow the US particle physics community to critically evaluate all aspects of the proposed US Superconducting Super Collider (SSC) in the light of conceptual design, progress in accelerator technology, new developments in collider physics, and innovations in instrumentation. Organized jointly by the European Committee for Future Accelerators (ECFA) and the Rheinisch-Westfälische Technische Hochschule in Aachen, a 'LEP 200' Workshop is being arranged from 29 September to 1 October to work out the physics objectives and experimental requirements for running LEP at around 100 GeV per beam. A four-day practical course on microelectronics is being hosted by CERN and the International School of Geneva.

Loans may keep CERN collider on target

CERN Multimedia

Abbott, A

1996-01-01

The European Laboratory for Particle Physics (CERN) is considering taking out bank loans to fund its Large Hadron Collider project. CERN officials are evaluating this option in view of the German government's decision to substantially reduce its annual contributions to the project. They state that the bank loans may be the only way to complete the project by the year 2005, especially if other contributing nations follow Germany's lead.

The new generation of PowerPC VMEbus front end computers for the CERN SPS and LEP accelerators system

CERN Document Server

Charrue, P; Ghinet, F; Ribeiro, P

1995-01-01

The CERN SPS and LEP PowerPC project is aimed at introducing a new generation of PowerPC VMEbus processor modules running the LynxOS real-time operating system. This new generation of front end computers using the state-of-the-art microprocessor technology will first replace the obsolete XENIX PC based systems (about 140 installations) successfully used since 1988 to control the LEP accelerator. The major issues addressed in the scope of this large scale project are the technical specification for the new PowerPC technology, the re-engineering aspects, the interfaces with other CERN wide projects, and the set up of a development environment. This project offers also support for other major SPS and LEP projects interested in the PowerPC microprocessor technology.

Experiments at CERN in 1997

International Nuclear Information System (INIS)

1997-11-01

This book summarises the current experimental programme at CERN. The experiments listed are taking place at one of the following machines: the Large Electron Positron Collider (LEP), the Super Proton Synchroton (SPS), the 28 GeV Proton Synchrotron (PS), including the Antiproton Decelerator (AD) for slow antiprotons and the ISOLDE facility for short-lived ions. The three experiments now approved for installation at the Large Hadron Collider (LHC) and the R and D projects aimed at the development of new detector technologies and data acquisition systems for the LHC experiments are also listed. (orig./WL)

1990 CERN School of Physics

International Nuclear Information System (INIS)

1992-01-01

The CERN School of Physics is intended to give young experimental physicists an introduction to the theoretical aspects of recent advances in elementary particle physics. These Proceedings contain reports of lectures on the following topics: Field theory, electroweak theory, physics beyond the Standard Model, QCD, heavy flavours and CP violation, results from LEP experiments, particle accelerator technology, tau charm factories, and the Large Hadron Collider project. (orig.)

1986 CERN school of physics

International Nuclear Information System (INIS)

1987-01-01

The CERN school of physics is intended to give young experimental physicists an introduction to the theoretical aspects of recent advances in elementary particle physics. These proceedings contain reports of lecture series on the following topics: introduction to symmetries and gauge theories, quark dynamics, experimental tests of gauge theories, proton antiproton collider results and detectors, physics at LEP, superphysics, and quantum black holes. (orig.)

People and things. CERN Courier, Apr 1986, v. 26(3)

International Nuclear Information System (INIS)

Anon.

1986-01-01

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events. A Summer Study to be held in Snowmass, Colorado, from 23 June to 11 July will allow the US particle physics community to critically evaluate all aspects of the proposed US Superconducting Super Collider (SSC) in the light of conceptual design, progress in accelerator technology, new developments in collider physics, and innovations in instrumentation. Organized jointly by the European Committee for Future Accelerators (ECFA) and the Rheinisch-Westfälische Technische Hochschule in Aachen, a 'LEP 200' Workshop is being arranged from 29 September to 1 October to work out the physics objectives and experimental requirements for running LEP at around 100 GeV per beam. A four-day practical course on microelectronics is being hosted by CERN and the International School of Geneva

The new generation of PowerPC VMEbus front end computers for the CERN SPS and LEP accelerators control system

CERN Document Server

Van den Eynden, M

1995-01-01

The CERN SPS and LEP PowerPC project is aimed at introducing a new generation of PowerPC VMEbus processor modules running the LynxOS real-time operating system. This new generation of front end computers using the state-of-the-art microprocessor technology will first replace the obsolete Xenix PC based systems (about 140 installations) successfully used since 1988 to control the LEP accelerator. The major issues addressed in the scope of this large scale project are the technical specification for the new PowerPC technology, the re-engineering aspects, the interfaces with other CERN wide projects, and the set up of a development environment. This project offers also support for other major SPS and LEP projects interested in the PowerPC microprocessor technology.

The Influence of Train Leakage Currents on the LEP Dipole Field

CERN Document Server

Bravin, Enrico; Dehning, Bernd; Drees, A; Galbraith, Peter; Geitz, M A; Henrichsen, K N; Koratzinos, M; Mugnai, G

1998-01-01

The determination of the mass and the width of the Z boson at CERN's LEP accelerator, an e+e- storage ring with a circumference of approximately 27 kilometres, imposes heavy demands on the knowledge of the LEP counter-rotating electron and positron beam energies. The precision required is of the order of 1 MeV or »20 ppm frequency. Due to its size the LEP collider is influenced by various macroscopic and regional factors such as the position of the moon or seasonal changes of the rainfall in the area, as reported earlier. A new and not less surprising effect of the LEP energy was observed in 1995: railroad trains in the Geneva region perturb the dipole field. A parasitic flow of electricity, originating from the trains, travels along the LEP ground cable and the vacuum chamber, interacting with the dipole field. An account of the phenomenon with its explanation substantiated by dedicated measurements is presented.

Using e-e+→ b bar b to test properties of new interactions at CERN LEP 2 and higher energies

International Nuclear Information System (INIS)

Gounaris, G.J.; Papadamou, D.T.; Renard, F.M.

1997-01-01

We show that in e - e + colliders at energies above the Z peak, the process e - e + →b bar b becomes very sensitive to the presence of residual new physics (NP) effects described by the dim=6 SU(3)xSU(2)xU(1) gauge invariant operators O qW , O qB , and O bB . This observation should be combined with the already known great sensitivity of the light fermion production through e - e + annihilation above the Z peak to the bosonic operators bar O DW and bar O DB . It is important to emphasize that the effects of all these operators are largely hidden at the Z peak; while they are enhanced beyond it since these operators grow like q 2 , a fact which becomes transparent when using the open-quotes Z-peak subtracted representation.close quotes The observability limits for detecting these operators at CERN LEP 2 and the Next Linear Collider, through such light fermion production processes, are also established. copyright 1997 The American Physical Society

CERN/KEK: Very high accelerating gradients

Energy Technology Data Exchange (ETDEWEB)

Anon.

1993-01-15

Full text: A world-wide effort is under way to develop linear electron-positron colliders so that physics experiments can be extended into a range of energies where circular machines (necessarily much larger than CERN's 27-kilometre LEP machine) would be crippled by synchrotron radiation. CERN is studying the feasibility of building a 2 TeV machine called CLIC powered not by individual klystrons, but by a high intensity electron 'drive' linac running parallel to the main linac (November 1990, page 7). This drive linac will itself be powered by similar superconducting cavities to those developed for LEP. A high gradient is an obvious design aim for any future high energy linear collider because it makes it shorter and therefore cheaper - the design figure for the CLIC machine is 80 MV/m. The CLIC study group has taken a significant step forward in demonstrating the technical feasibility of their machine by achieving peak and average accelerating gradients of 137 MV/m and 84 MV/m respectively in a short section of accelerating structure during high gradient tests at the Japanese KEK Laboratory last year. This result obtained within the framework of a CERN/KEK collaboration on linear colliders was obtained using a 20-cell accelerating section built at CERN using state-of the- art technology which served both as a model for CLIC studies as well as a prototype for the Japanese Linear Collider studies. The operating frequency of the model accelerating section is 2.6 times lower than the CLIC frequency but was chosen because a high power r.f. source and pulse compression scheme has been developed for this frequency at KEK. Testing CLIC models at 11.4 GHz is however more stringent than at 30 GHz because the chance of electrical breakdown increases as the frequency is lowered. This recent result clearly demonstrates that a gradient of 80 MV/m is feasible.

CERN/KEK: Very high accelerating gradients

International Nuclear Information System (INIS)

Anon.

1993-01-01

Full text: A world-wide effort is under way to develop linear electron-positron colliders so that physics experiments can be extended into a range of energies where circular machines (necessarily much larger than CERN's 27-kilometre LEP machine) would be crippled by synchrotron radiation. CERN is studying the feasibility of building a 2 TeV machine called CLIC powered not by individual klystrons, but by a high intensity electron 'drive' linac running parallel to the main linac (November 1990, page 7). This drive linac will itself be powered by similar superconducting cavities to those developed for LEP. A high gradient is an obvious design aim for any future high energy linear collider because it makes it shorter and therefore cheaper - the design figure for the CLIC machine is 80 MV/m. The CLIC study group has taken a significant step forward in demonstrating the technical feasibility of their machine by achieving peak and average accelerating gradients of 137 MV/m and 84 MV/m respectively in a short section of accelerating structure during high gradient tests at the Japanese KEK Laboratory last year. This result obtained within the framework of a CERN/KEK collaboration on linear colliders was obtained using a 20-cell accelerating section built at CERN using state-of the- art technology which served both as a model for CLIC studies as well as a prototype for the Japanese Linear Collider studies. The operating frequency of the model accelerating section is 2.6 times lower than the CLIC frequency but was chosen because a high power r.f. source and pulse compression scheme has been developed for this frequency at KEK. Testing CLIC models at 11.4 GHz is however more stringent than at 30 GHz because the chance of electrical breakdown increases as the frequency is lowered. This recent result clearly demonstrates that a gradient of 80 MV/m is feasible

Heavy quark and quarkonium production at CERN LEP2. kT-factorization versus data

International Nuclear Information System (INIS)

Lipatov, A.V.; Zotov, N.P.

2005-02-01

We present calculations of heavy quark and quarkonium production at CERN LEP2 in the κ T -factorization QCD approach. Both direct and resolved photon contribution are taken into account. The conservative error analysis is performed. The unintegrated gluon distribution in the photon is obtained from the full CCFM evolution equation. The traditional color-singlet mechanism to describe non-perturbative transition of QQ-pair into a final quarkonium is used. Our analysis covers polarization properties of heavy quarkonia at moderate and large transverse momenta. We find that the total and differential open charm production cross sections are consistent with the recent experimental data taken by the L3, OPAL and ALEPH collaborations. At the same time the DELPHI data for the inclusive J/ψ production exceed our predictions but experimental uncertainties are too large to claim a significant inconsistency. The bottom production in photon-photon collisions at CERN LEP2 is hard to explain within the κ T -factorization formalism. (orig.)

[European particle accelerator conference, Rome, Italy, and visit to the LEP storage ring and LEP detectors L3 and ALEPH at CERN, Geneva, Switzerland, June 5-16, 1988]: Foreign trip report

International Nuclear Information System (INIS)

Blumberg, L.N.

1988-01-01

A selection of papers presented at the EPAC Conference relating to accelerator technology, facilities proposed, planned or under construction, and operating machines are discussed. Also noted are discussions at CERN with personnel from the LEP superconducting RF, the LEP L3 and ALEPH detectors, and the LHC superconducting magnet groups

CERN: Fixed target targets

International Nuclear Information System (INIS)

Anon.

1993-01-01

Full text: While the immediate priority of CERN's research programme is to exploit to the full the world's largest accelerator, the LEP electron-positron collider and its concomitant LEP200 energy upgrade (January, page 1), CERN is also mindful of its long tradition of diversified research. Away from LEP and preparations for the LHC proton-proton collider to be built above LEP in the same 27-kilometre tunnel, CERN is also preparing for a new generation of heavy ion experiments using a new source, providing heavier ions (April 1992, page 8), with first physics expected next year. CERN's smallest accelerator, the LEAR Low Energy Antiproton Ring continues to cover a wide range of research topics, and saw a record number of hours of operation in 1992. The new ISOLDE on-line isotope separator was inaugurated last year (July, page 5) and physics is already underway. The remaining effort concentrates around fixed target experiments at the SPS synchrotron, which formed the main thrust of CERN's research during the late 1970s. With the SPS and LEAR now approaching middle age, their research future was extensively studied last year. Broadly, a vigorous SPS programme looks assured until at least the end of 1995. Decisions for the longer term future of the West Experimental Area of the SPS will have to take into account the heavy demand for test beams from work towards experiments at big colliders, both at CERN and elsewhere. The North Experimental Area is the scene of larger experiments with longer lead times. Several more years of LEAR exploitation are already in the pipeline, but for the longer term, the ambitious Superlear project for a superconducting ring (January 1992, page 7) did not catch on. Neutrino physics has a long tradition at CERN, and this continues with the preparations for two major projects, the Chorus and Nomad experiments (November 1991, page 7), to start next year in the West Area. Delicate neutrino oscillation effects could become

CERN: Fixed target targets

Energy Technology Data Exchange (ETDEWEB)

Anon.

1993-03-15

Full text: While the immediate priority of CERN's research programme is to exploit to the full the world's largest accelerator, the LEP electron-positron collider and its concomitant LEP200 energy upgrade (January, page 1), CERN is also mindful of its long tradition of diversified research. Away from LEP and preparations for the LHC proton-proton collider to be built above LEP in the same 27-kilometre tunnel, CERN is also preparing for a new generation of heavy ion experiments using a new source, providing heavier ions (April 1992, page 8), with first physics expected next year. CERN's smallest accelerator, the LEAR Low Energy Antiproton Ring continues to cover a wide range of research topics, and saw a record number of hours of operation in 1992. The new ISOLDE on-line isotope separator was inaugurated last year (July, page 5) and physics is already underway. The remaining effort concentrates around fixed target experiments at the SPS synchrotron, which formed the main thrust of CERN's research during the late 1970s. With the SPS and LEAR now approaching middle age, their research future was extensively studied last year. Broadly, a vigorous SPS programme looks assured until at least the end of 1995. Decisions for the longer term future of the West Experimental Area of the SPS will have to take into account the heavy demand for test beams from work towards experiments at big colliders, both at CERN and elsewhere. The North Experimental Area is the scene of larger experiments with longer lead times. Several more years of LEAR exploitation are already in the pipeline, but for the longer term, the ambitious Superlear project for a superconducting ring (January 1992, page 7) did not catch on. Neutrino physics has a long tradition at CERN, and this continues with the preparations for two major projects, the Chorus and Nomad experiments (November 1991, page 7), to start next year in the West Area. Delicate neutrino oscillation effects could become visible for the first

Phenomenology at the CERN pp-bar collider

International Nuclear Information System (INIS)

Phillips, R.J.N.

1986-05-01

The paper concerns some comparisons of theory with high-psub(T) data from the CERN pp-bar collider, beginning with some background about the machine and detectors. Later sections describe weak boson searches, high psub(T) jets, heavy quark phenomena and possible E 6 exotica from superstrings. (author)

Towards the International Linear Collider

International Nuclear Information System (INIS)

Lopez-Fernandez, Ricardo

2006-01-01

The broad physics potential of e+e- linear colliders was recognized by the high energy physics community right after the end of LEP in 2000. In 2007, the Large Hadron Collider (LHC) now under construction at CERN will obtain its first collisions. The LHC, colliding protons with protons at 14 TeV, will discover a standard model Higgs boson over the full potential mass range, and should be sensitive to new physics into the several TeV range. The program for the Linear Collider (LC) will be set in the context of the discoveries made at the LHC. All the proposals for a Linear Collider will extend the discoveries and provide a wealth of measurements that are essential for giving deeper understanding of their meaning, and pointing the way to further evolution of particle physics in the future. For the mexican groups is the right time to join such an effort

b-tagging in DELPHI at LEP

CERN Document Server

Abdallah, J; Adam, W; Adye, T; Adzic, P; Albrecht, T; Alderweireld, T; Alemany-Fernandez, R; Allmendinger, T; Allport, P P; Almehed, S; Amaldi, Ugo; Amapane, N; Amato, S; Anashkin, E; Andreazza, A; Andringa, S; Anjos, N; Antilogus, P; Apel, W D; Arnoud, Y; Ask, S; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Ballestrero, A; Bambade, P; Barbier, R; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Bates, M; Battaglia, Marco; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Benekos, N C; Benvenuti, Alberto C; Bérat, C; Berggren, M; Berntzon, L; Bertrand, D; Besançon, M; Besson, N; Bibby, J; Biffi, P; Bloch, D; Blom, M; Bonesini, M; Boonekamp, M; Booth, P S L; Borisov, G; Botner, O; Bouquet, B; Bowcock, T J V; Boyko, I; Bracko, M; Branchini, P; Brenner, R; Brodet, E; Brückman, P; Brunet, J M; Bugge, L; Buschmann, P; Caccia, M; Calvi, M; Camporesi, T; Canale, V; Carena, F; Castro, N; Cavallo, F R; Chabaud, V; Chapkin, M M; Charpentier, P; Checchia, P; Chierici, R; Shlyapnikov, P; Chudoba, J; Chung, S U; Cieslik, K; Collins, P; Contri, R; Cosme, G; Cossutti, F; Costa, M J; Couchot, F; Crawley, B; Crennell, D J; Cuevas-Maestro, J; D'Almagne, B; D'Hondt, J; Dalmau, J; Da Silva, T; Da Silva, W; Della Ricca, G; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Maria, N; De Min, A; De Paula, L S; Di Ciaccio, Lucia; Dijkstra, H; Di Simone, A; Doroba, K; Drees, J; Dris, M; Eigen, G; Ekelöf, T J C; Ellert, M; Elsing, M; Espirito-Santo, M C; Fanourakis, G K; Fassouliotis, D; Feindt, M; Fernández, J; Ferrer, A; Ferro, F; Flagmeyer, U; Föth, H; Fokitis, E; Fulda-Quenzer, F; Fuster, J A; Gandelman, M; García, C; Gavillet, P; Gazis, E N; Geralis, T; Gokieli, R; Golob, B; Gómez-Cadenas, J J; Gómez-Ceballos, G; Gonçalves, P; Graziani, E; Grosdidier, G; Grzelak, K; Guy, J; Haag, C; Hallgren, A; Hamacher, K; Hamilton, K; Hansen, J; Haug, S; Hauler, F; Hedberg, V; Hennecke, M; Hernando, J A; Herr, H; Heuser, J M; Holmgren, S O; Holt, P J; Houlden, M A; Hultqvist, K; Jackson, J N; Jalocha, P; Jarlskog, C; Jarlskog, G; Jarry, P; Jeans, D; Johansson, E K; Johansson, P D; Jonsson, P; Joram, C; Jungermann, L; Kapusta, F; Karlsson, M; Katsanevas, S; Katsoufis, E C; Keränen, R; Kernel, G; Kersevan, Borut P; Kiiskinen, A P; King, B T; Kjaer, N J; Kluit, P; Kokkinias, P; Kourkoumelis, C; Kuznetsov, O; Krumshtein, Z; Kucharczyk, M; Kucewicz, W; Kurowska, J; Lamsa, J; Leder, G; Ledroit, F; Leinonen, L; Leitner, R; Lemonne, J; Lepeltier, V; Lesiak, T; Liebig, W; Liko, D; Lipniacka, A; Lopes, J H; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J; Malek, A; Maltezos, S; Mandl, F; Marco, J; Marco, R; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Masik, J; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Mazzucato, F; Mazzucato, M; McNulty, R; Meroni, C; Meyer, W T; Migliore, E; Mitaroff, W A; Mjörnmark, U; Moa, T; Moch, M; Mönig, K; Monge, R; Montenegro, J; Moraes, D; Moreno, S; Morettini, P; Müller, U; Münich, K; Mulders, M; Mundim, L; Murray, W; Muryn, B; Myatt, Gerald; Myklebust, T; Nassiakou, M; Navarria, Francesco Luigi; Nawrocki, K; Nicolaidou, R; Niezurawski, P; Nikolenko, M; Nomerotski, A; Norman, A; Nygren, A; Oblakowska-Mucha, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Österberg, K; Ouraou, A; Oyanguren, A; Paganoni, M; Paiano, S; Palacios, J P; Palka, H; Papadopoulou, T D; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Peralta, L; Perepelitsa, V F; Perrotta, A; Petrolini, A; Piedra, J; Pieri, L; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Poireau, V; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Pukhaeva, N; Pullia, Antonio; Rames, J; Ramler, L; Read, A; Rebecchi, P; Rehn, J; Reid, D; Reinhardt, R; Renton, P B; Richard, F; Rídky, J; Rivero, M; Rodríguez, D; Romero, A; Ronchese, P; Rosenberg, E I; Roudeau, Patrick; Rovelli, T; Ruhlmann-Kleider, V; Ryabtchikov, D; Sadovskii, A; Salmi, L; Salt, J; Savoy-Navarro, A; Schwickerath, U; Segar, A; Sekulin, R L; Siebel, M; Sissakian, A N; Smadja, G; Smirnova, O G; Sokolov, A; Sopczak, A; Sosnowski, R; Spassoff, Tz; Stanitzki, M; Stavitski, I; Stocchi, A; Strauss, J; Stugu, B; Szczekowski, M; Szeptycka, M; Szumlak, T; Tabarelli de Fatis, T; Taffard, A C; Tegenfeldt, F; Timmermans, J; Tinti, N; Tkatchev, L G; Tobin, M; Todorovova, S; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortosa, P; Travnicek, P; Treille, D; Trischuk, W; Tristram, G; Trochimczuk, M; Troncon, C; Turluer, M L; Tyapkin, I A; Tyapkin, P; Tyndel, M; Tzamarias, S; Uvarov, V; Valenti, G; van Dam, P; Van Eldik, J; Van Lysebetten, A; Van Remortel, N; Van Vulpen, I B; Vegni, G; Veloso, F; Venus, W A; Verbeure, F; Verdier, P; Verzi, V; Vilanova, D; Vitale, L; Vrba, V; Wahlen, H; Washbrook, A J; Weilhammer, Peter; Weiser, C; Wicke, D; Wickens, J H; Wilkinson, G; Winter, M; Witek, M; Yushchenko, O P; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zimin, N I; Zinchenko, A I; Zupan, M

2004-01-01

The standard method used for tagging b-hadrons in the DELPHI experiment at the CERN LEP Collider is discussed in detail. The main ingredient of b-tagging is the impact parameters of tracks, which relies mostly on the vertex detector. Additional information, such as the mass of particles associated to a secondary vertex, significantly improves the selection efficiency and the background suppression. The paper describes various discriminating variables used for the tagging and the procedure of their combination. In addition, applications of b-tagging to some physics analyses, which depend crucially on the performance and reliability of b-tagging, are described briefly.

Polarization at LEP. Vol. 2

International Nuclear Information System (INIS)

Alexander, G.; Altarelli, G.; Blondel, A.; Coignet, G.; Keil, E.; Plane, D.E.; Treille, D.

1988-01-01

This report contains a collection of papers covering the most important part of studies carried out by five study groups in view of a programme of experiments with polarized beams at LEP, the Large Electron-Positron collider under construction at CERN. The emphasis is on precision measurements at the Z peak. Such measurements are shown to be of considerable theoretical interest as well as very clean from the point of view of theoretical and experimental uncertainties. The measurement of the beam polarization can certainly be performed with sufficient accuracy, thanks to the availability of both e + and e - beam polarization. The normalization of the data taken with different beam helicities poses certain constraints that are described. Substantial progress has been made in understanding the possibility of providing longitudinally polarized beams in the LEP machine: The design of new wigglers and spin rotators, the study of correction procedures and results of numerical simulations are presented. (orig.)

3rd CERN-Fermilab Hadron Collider Physics Summer School

CERN Multimedia

2008-01-01

August 12-22, 2008, Fermilab The school web site is http://cern.ch/hcpss with links to the academic programme and the application procedure. The APPLICATION DEADLINE IS 29 FEBRUARY 2008. The goal of the CERN-Fermilab Hadron Collider Physics Summer Schools is to offer students and young researchers in high-energy physics a concentrated syllabus on the theory and experimental challenges of hadron collider physics. The third session of the summer school will focus on exposing young post-docs and advanced graduate students to broader theories and real data beyond what they’ve learned at their home institutions. Experts from across the globe will lecture on the theoretical and experimental foundations of hadron collider physics, host parallel discussion sessions and answer students’ questions. This year’s school will also have a greater focus on physics beyond the Standard Model, as well as more time for questions at the end of each lecture. The 2008 School will be held at ...

3rd CERN-Fermilab HadronCollider Physics Summer School

CERN Multimedia

EP Department

2008-01-01

August 12-22, 2008, Fermilab The school web site is http://cern.ch/hcpss with links to the academic programme and the application procedure. The APPLICATION DEADLINE IS 29 FEBRUARY 2008. The goal of the CERN-Fermilab Hadron Collider Physics Summer Schools is to offer students and young researchers in high-energy physics a concentrated syllabus on the theory and experimental challenges of hadron collider physics. The third session of the summer school will focus on exposing young post-docs and advanced graduate students to broader theories and real data beyond what they’ve learned at their home institutions. Experts from across the globe will lecture on the theoretical and experimental foundations of hadron collider physics, host parallel discussion sessions and answer students’ questions. This year’s school will also have a greater focus on physics beyond the Standard Model, as well as more time for questions at the end of each lecture. The 2008 School will be held at Fermilab. Further enquiries should ...

Charmed-hadron fragmentation functions from CERN LEP1 revisted

International Nuclear Information System (INIS)

Kniehl, B.A.; Kramer, G.

2006-07-01

In Phys. Rev. D 58, 014014 (1998) and 71, 094013 (2005), we determined non-perturbative D 0 , D + , D *+ , D s + , and Λ c + fragmentation functions, both at leading and next-to-leading order in the MS factorization scheme, by fitting e + e - data taken by the OPAL Collaboration at CERN LEP1. The starting points for the evolution in the factorization scale μ were taken to be μ 0 -2m Q , where Q = c, b. For the reader's convenience, in this Addendum, we repeat this analysis for μ 0 =m Q , where the flavor thresholds of modern sets of parton density functions are located. (Orig.)

Follow-up research at CERN

International Nuclear Information System (INIS)

1993-01-01

At The European Center for High Energy Physics (Conseil Europeen de Recherche Nucleaire - CERN) basic research is carried out based on some of the world's largest particle accelerators, especially the Large Electron Positron collider (LEP). Danish membership of CERN gives Danish physicists access to these machines and the Accelerator Committee offers advice on their utilization and related financing. Danish research carried out at CERN is described, based on contributions from individual research groups. The functions, administration and budgets of the Accelerator Committee are explained in addition to other forms of administration connected with CERN, such as the Danish CERN Delegation, and an evaluation of Danish experimentation within physics is presented. Information is given on individual Danish members of the CERN groups of scientists and a list of the publications of international research groups which include Danish subjects, covering the years 1991-93, is presented. The publication is related to the delegation of grants for research projects carried out by Danish physicists. (AB)

After LEP

International Nuclear Information System (INIS)

Anon.

1986-01-01

The idea emerged for a ring of superconducting magnets, installed above the LEP ring, to collide protons together (or protons with antiprotons) at as high an energy as possible. Some work has been done to firm up the ideas for the new Collider: determining the best configuration for the proton-proton option and establishing its advantages over a realistic proton-antiproton option; assessing collisions between the electron beam of LEP and one proton beam; designing a complete section of the machine; making tentative designs of superconducting magnets providing between 8 and 10 tesla, and working out a European magnet development programme towards this goal; outlining where and how the various types of collisions could be exploited in the LEP tunnel. (orig./HSI).

"Towards a Future Linear Collider" and "The Linear Collider Studies at CERN"

CERN Document Server

CERN. Geneva

2010-01-01

During the week 18-22 October, more than 400 physicists will meet at CERN and in the CICG (International Conference Centre Geneva) to review the global progress towards a future linear collider. The 2010 International Workshop on Linear Colliders will study the physics, detectors and accelerator complex of a linear collider covering both the CLIC and ILC options. Among the topics presented and discussed will be the progress towards the CLIC Conceptual Design Report in 2011, the ILC Technical Design Report in 2012, physics and detector studies linked to these reports, and an increasing numbers of common working group activities. The seminar will give an overview of these topics and also CERN’s linear collider studies, focusing on current activities and initial plans for the period 2011-16. n.b: The Council Chamber is also reserved for this colloquium with a live transmission from the Main Auditorium.

LEP is upgraded

CERN Multimedia

1995-01-01

A superconducting radio-frequency cavity is installed on the Large Electron-Positron (LEP) collider. This upgrade, known as LEP-2, allowed the accelerator to reach new, higher energies and so investigate new areas of physics.

LEP3: A High Luminosity e+e- Collider to Study the Higgs Boson

CERN Document Server

Blondel, A U; Assmann, R W; Butterworth, A; Janot, P; Jimenez, J M; Grojean, C; Milanese, A; Modena, M; Osborne, J A; Zimmermann, F; Piekarz, H; Oide, K; Yokoya, K; Ellis, J; Klute, M; Zanetti, M; Velasco, M; Telnov, V; Rivkin, L; Cai, Y

2012-01-01

The LHC experiments have discovered a new particle with a mass around 125 GeV that is a strong candidate for the scalar Higgs boson expected in the Standard Model. An e+e− collider operating close to the ZH threshold (at a centre-of-mass energy of 240 GeV) could be the tool of choice for studying this unique particle in detail. We present here the concept of a storage ring collider, which we call LEP3. Preliminary studies show that at a centre-of-mass energy of 240 GeV, near-constant luminosities of 1034 cm-2s-1 are possible in up to four collision points, while respecting a number of constraints including beamstrahlung limits. With an integrated luminosity of 100fb-1 per year and per interaction point, 20,000 e+e- - ZH events would be produced per year and per experiment. LEP3 could also operate in multi-bunch mode at the Z resonance, with luminosities of several×1035cm-2s-1, yielding O(1011) Z decays per year, as well as just above the WW threshold, potentially improving our knowledge of W and Z propert...

Third intervention of Gilles Jobin and Collide@CERN

CERN Document Server

2012-01-01

Everything you wanted to know about contemporary dance but were afraid to ask. - 4 September 2012 at 4 p.m. in the Council Chamber -   A subjective and personal presentation of the recent history of contemporary dance by Gilles Jobin, Collide@CERN choreographer in residence.

Comparison of Different Methods for Transverse Emittance Measurement and Recent Results from LEP

CERN Document Server

Bovet, Claude; Jung, R

1997-01-01

The knowledge of its position and angular transverse distributions is of utmost interest to assess the good behaviour of a beam within an accelerator. After a short reminder of beam "emittance" definitions, a review is made of various measurement techniques used so far both in single pass machines and colliders. Results of measurements made at CERN in the future LHC injection complex and in LEP are presented and discussed.

LEP commissioning

International Nuclear Information System (INIS)

Anon.

1989-01-01

On 14 July, as ail France celebrated the bicentenary of its revolution, CERN was the scene of a revolution of a very different kind. At 16.30 hrs, a 20 GeV positron beam went round the 27 kilometres (most of which is under French territory) of CERN's new LEP electron-positron storage ring. After more than a decade of careful planning and preparation, almost six years after groundbreaking, and two years after the start of equipment installation, the LEP team delivered on the day they had told people to mark five years ago

Searching for light Higgs scalar boson in the next generation of electron-positron collider at LEP

International Nuclear Information System (INIS)

Chukwumah, G.C.

1985-11-01

The e + e - -collider facilities at LEP II, with the cm energy √S in the range 100-170 GeV may be able to detect ''light'' Higgs bosons, assuming a high luminosity. In this paper, we have calculated production cross-sections of a light Higgs boson H 0 in association with the neutral gauge boson Z 0 , for varying ranges of the cm energy expected to be available to LEP II and VLEEP (Novosibirsk) and for various values of the light Higgs mass. It is found out that production cross-sections are sizeable in comparison with those for the very massive Higgs bosons in proton-anti(proton) super-colliders, Tevatron, Spp-barS and SSC, respectively. The implication of this feature is pointed out. Further, prospects for light Higgs production in association with the charged gauge boson, W - in ultra energetic neutrino beams are examined. (author)

People and things. CERN Courier, Oct 1991, v. 31(8)

Energy Technology Data Exchange (ETDEWEB)

Anon.

1991-10-15

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events: ; Hampton University Graduate Studies (HUGS) at CEBAF, a summer program in electromagnetic nuclear physics held at the Continuous Electron Beam Accelerator Facility, Newport News, Virginia, has completed its sixth year. ; With research and development work pushing ahead for the experimental programme at the proposed LHC proton collider in CERN's LEP tunnel, attention is also turning to preparations for the experiments themselves.

Searches for supersymmetry at high-energy colliders

International Nuclear Information System (INIS)

Feng, Jonathan L.; Grivaz, Jean-Francois; Nachtman, Jane

2010-01-01

This review summarizes the state of the art in searches for supersymmetry at colliders on the eve of the Large Hadron Collider era. Supersymmetry is unique among extensions of the standard model in being motivated by naturalness, dark matter, and force unification, both with and without gravity. At the same time, weak-scale supersymmetry encompasses a wide range of experimental signals that are also found in many other frameworks. Motivations for supersymmetry are recalled and the various models and their distinctive features are reviewed. Searches for neutral and charged Higgs bosons and standard-model superpartners at the high energy frontier are summarized comprehensively, considering both canonical and noncanonical supersymmetric models, and including results from the LEP collider at CERN, HERA at DESY, and the Fermilab Tevatron.

There’s more to particle physics at CERN than colliders

CERN Multimedia

2016-01-01

CERN’s scientific programme must be compelling, unique, diverse, and integrated into the global landscape of particle physics. One of the Laboratory’s primary goals is to provide a diverse range of excellent physics opportunities and to put its unique facilities to optimum use, maximising the scientific return.   In this spirit, we have recently established a Physics Beyond Colliders study group with a mandate to explore the unique opportunities offered by the CERN accelerator complex to address some of today’s outstanding questions in particle physics through projects complementary to high-energy colliders and other initiatives in the world. The study group will provide input to the next update of the European Strategy for Particle Physics. The process kicked off with a two-day workshop at CERN on 6 and 7 September, organised by the study group conveners: Joerg Jaeckel (Heidelberg), Mike Lamont (CERN) and Claude Vallée (CPPM Marseille and DESY). Its purpo...

For Information: CERN-Fermilab2006 Hadron Collider Physics Summer School

CERN Multimedia

2006-01-01

Applications are Now Open for the CERN-Fermilab2006 Hadron Collider Physics Summer School August 9-18, 2006 Please go to the school web site http://hcpss.fnal.gov/ and follow the links to the Application process. The APPLICATION DEADLINE IS APRIL 8, 2006. Successful applicants and support awards will be announced shortly thereafter. Also available on the web is the tentative academic program of the school. The main goal of the CERN-Fermilab Hadron Collider Physics Summer Schools is to offer students and young researchers a broad picture of both the theoretical and experimental aspects of hadron collider physics. The emphasis of the first school will be on the physics potential of the first years of data taking at the LHC, and on the experimental and theoretical tools needed to exploit that potential. A series of lectures and informal discussions will include an introduction to the theoretical and phenomenological framework of hadron collisions, and current theoretical models of frontier physics, as...

The CERN SPS proton–antiproton collider

CERN Document Server

Schmidt, Rudiger

2016-01-01

One of CERN's most ambitious and successful projects was the search for the intermediate bosons, W and Z [1]. The accelerator part of the project relied on a number of innovations in accelerator physics and technology. The invention of the method of stochastic cooling and the extension by many orders of magnitude beyond the initial proof of principle demonstration allowed the construction of the Antiproton Accumulator. Major modifications to the 26 GeV PS complex and the conversion of the 300 GeV SPS, which had just started up as an accelerator, to a collider were required. The SPS collider had to master the beam–beam effect far beyond limits reached before and had to function in a tight symbiosis with the UA1 and UA2 experiments.

LEP at 90°

Energy Technology Data Exchange (ETDEWEB)

Anon.

1993-01-15

With twice as many Z particles logged this year, the performance of CERN's LEP electron-positron collider continues to improve. Paradoxically, the improvement would have been even better had it not been for teething problems with new operating conditions which will eventually boost performance still higher. Now solidly established, these new conditions, notably the 90° (instead of the previous 60°) phase for transverse betatron oscillations, and the 'pretzel' scheme for eight bunches per beam instead of four (October, page 17), first had to be assimilated, and it took a few weeks before the LEP operating crews could add them to their full repertoire. Collision performance (measured by 'luminosity') continues to improve. Although in principle LEP has yet to deliver its 'design' luminosity of 1.3 x 10{sup 31} per sq cm per s at any one time, its best performance to date is not far off - 1.1 x 10{sup 31}. The crews have become very skilled at optimizing conditions during each beam coast, with continual careful grooming of the beams ensuring high collision rates. This, together with improved performance at the four detectors - Aleph, Delphi, L3, and Opal - have led to average efficiency increasing to 57% from 44% in 1991, so that the luminosity delivered over a day has exceeded what could have been expected initially, says Steve Myers.

LEP at 90°

International Nuclear Information System (INIS)

Anon.

1993-01-01

With twice as many Z particles logged this year, the performance of CERN's LEP electron-positron collider continues to improve. Paradoxically, the improvement would have been even better had it not been for teething problems with new operating conditions which will eventually boost performance still higher. Now solidly established, these new conditions, notably the 90° (instead of the previous 60°) phase for transverse betatron oscillations, and the 'pretzel' scheme for eight bunches per beam instead of four (October, page 17), first had to be assimilated, and it took a few weeks before the LEP operating crews could add them to their full repertoire. Collision performance (measured by 'luminosity') continues to improve. Although in principle LEP has yet to deliver its 'design' luminosity of 1.3 x 10 31 per sq cm per s at any one time, its best performance to date is not far off - 1.1 x 10 31 . The crews have become very skilled at optimizing conditions during each beam coast, with continual careful grooming of the beams ensuring high collision rates. This, together with improved performance at the four detectors - Aleph, Delphi, L3, and Opal - have led to average efficiency increasing to 57% from 44% in 1991, so that the luminosity delivered over a day has exceeded what could have been expected initially, says Steve Myers

Observations on LEP with a view to SSC

International Nuclear Information System (INIS)

Toohig, T.E.

1984-01-01

From 24-29 October 1984 a visit was made to the LEP project at CERN with a view to extracting from the LEP planning and experience what might be useful in planning an SSC. With a circumference of 26.7 km, in a reasonably densely-populated area outside the boundaries of the CERN site, LEP already faces most of the problems of environment, public relations, maintenance and operation that will be faced by an SSC project. Information is presented under the headings of: (1) radiation protection; (2) heating, ventilation, and airconditioning; (3) electrical power distribution; (4) LEP experiments/UA1, UA2; (5) civil; (6) infrastructure installation; (7) survey; (8) safety; and (9) LEP controls. Each report lists the CERN individuals who generously provided their insights and help

The ATLAS experiment at the CERN Large Hadron Collider

NARCIS (Netherlands)

Aad, G.; et al., [Unknown; Bentvelsen, S.; Bobbink, G.J.; Bos, K.; Boterenbrood, H.; Brouwer, G.; Buis, E.J.; Buskop, J.J.F.; Colijn, A.P.; Dankers, R.; Daum, C.; de Boer, R.; de Jong, P.; Ennes, P.; Gosselink, M.; Groenstege, H.; Hart, R.G.G.; Hartjes, F.; Hendriks, P.J.; Hessey, N.P.; Jansweijer, P.P.M.; Kieft, G.; Klok, P.F.; Klous, S.; Kluit, P.; Koffeman, E.; Koutsman, A.; Liebig, W.; Limper, M.; Linde, F.; Luijckx, G.; Massaro, G.; Muijs, A.; Peeters, S.J.M.; Reichold, A.; Rewiersma, P.; Rijpstra, M.; Scholte, R.C.; Schuijlenburg, H.W.; Snuverink, J.; van der Graaf, H.; van der Kraaij, E.; van Eijk, B.; van Kesteren, Z.; van Vulpen, I.; Verkerke, W.; Vermeulen, J.C.; Vreeswijk, M.; Werneke, P.

2008-01-01

The ATLAS detector as installed in its experimental cavern at point 1 at CERN is described in this paper. A brief overview of the expected performance of the detector when the Large Hadron Collider begins operation is also presented.

People and things. CERN Courier, Oct 1991, v. 31(8)

International Nuclear Information System (INIS)

Anon.

1991-01-01

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events: ; Hampton University Graduate Studies (HUGS) at CEBAF, a summer program in electromagnetic nuclear physics held at the Continuous Electron Beam Accelerator Facility, Newport News, Virginia, has completed its sixth year. ; With research and development work pushing ahead for the experimental programme at the proposed LHC proton collider in CERN's LEP tunnel, attention is also turning to preparations for the experiments themselves

CERN Council pauses for effect (LHC approval a step nearer)

International Nuclear Information System (INIS)

Anon.

1994-01-01

Aweek of intense diplomatic activity which had high level telephones ringing across Europe culminated in an imaginative and unexpected move on 24 June, when delegates adjourned the 100th session of CERN's governing body, Council, to be reconvened at a later date. On the Council table was the vote for CERN's next major machine, now universally agreed as the world focus of particle physics research for the start of the 21st century, the LHC proton-proton collider, to be built in CERN's 27-kilometre LEP tunnel, and the largest and most complex scientific joint effort ever undertaken in Europe

CERN and Israel

International Nuclear Information System (INIS)

Anon.

1995-01-01

Israel (along with the US, Japan, Canada, the Russian Federation and India) is one of the CERN non- Member State nations targeted for substantial future participation in CERN's experimental programme, in particular for the LHC proton collider to be built in the 27-kilometre LEP tunnel and which was formally approved by CERN Council in December (January/February, page 1). In keeping with their illustrious scientific traditions, Israeli experimental physicists have collaborated in experiments at many of the world's major high energy Laboratories - Brookhaven, Fermilab and SLAC in the US, and in Europe, DESY, Hamburg, as well as CERN. However CERN, as the geographically closest major Laboratory (as well as the largest), plays a special role for Israeli scientists. At CERN, the advent of preparations in the early 1980s for the experimental programme at the LEP electron-positron collider was the signal for Israeli researchers to mount a concerted effort and contribute to one of the experiments - Opal - at a level comparable to that of major nations. This allowed Israeli teams to participate fully in the planning and construction phase of this branch of Big Science. Underlining this commitment, and to coordinate the various national agencies involved in this aspect of Big Science, in 1983 the Israel Commission for High Energy Physics (ICHEP) was formed. It is currently chaired by David Horn of Tel Aviv. The initial ICHEP/CERN contract established the official CERN/lsrael link under which, in the short-term, teams from three major research centres - the Weizmann Institute, Tel- Aviv University, and Haifa's Technion - contributed to Opal, as the flagship experiment, while providing a framework for longer-term collaboration. (At CERN, Israeli physicists also participate in the NA45 heavy ion experiment and the NA47 Spin Muon Collaboration - SMC.) Opal groups some 320 scientists from 32 research centres in eight countries, and includes a 21-strong Israeli

The new generation of PowerPC VMEbus front end computers for the CERN SPS and LEP accelerators system

OpenAIRE

Charrue, P; Bland, A; Ghinet, F; Ribeiro, P

1995-01-01

The CERN SPS and LEP PowerPC project is aimed at introducing a new generation of PowerPC VMEbus processor modules running the LynxOS real-time operating system. This new generation of front end computers using the state-of-the-art microprocessor technology will first replace the obsolete XENIX PC based systems (about 140 installations) successfully used since 1988 to control the LEP accelerator. The major issues addressed in the scope of this large scale project are the technical specificatio...

Detectors for large e/sup +/e/sup -/ colliders

International Nuclear Information System (INIS)

Baltay, C.

1986-01-01

In this paper the author gives a brief review of the detectors now being built for the two new large e/sup +/e/sup -/ colliders, LEP, under construction at CERN, and the SLC, now under construction at SLAC. These colliders are intended to study the Z 0 energy region and above, with energies of around 100 to 200 GeV in the center of mass. The purpose of this paper is to list some of the physics topics of interest and given an indication of the requirements they make on the design of the detectors. It also contains a brief discussion giving some of the relevant parameters of the colliers, and gives a description of the large detectors now under construction to utilize these colliders

CERN to start Large Hadron Collider november 2007

CERN Multimedia

2006-01-01

"The Large Hadron Collider (LHC) is expected to provide its first collisions in November 2007, CERN has announced. A two-month run at 0.9 TeV is planned for 2007 to test the accelerating and detecting equipment, and a full power run at 14 TeV is expected in the spring of 2008."

People and things. CERN Courier, May 1990, v.30(4)

Energy Technology Data Exchange (ETDEWEB)

Anon.

1990-05-15

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events: ; Implications for 'dark matter' - the invisible mass of the Universe - were a talking point at the recent astrophysics workshop in the Moriond series, and a focus of the meeting 'LEP and the Universe' at CERN. ; This year's DESY Theory Workshop from 1-3 October will be on 'Waiting for the Top Quark'. ; To explore in detail and update the physics possibilities for the Large Hadron Collider (LHC) project at CERN, the European Committee for Future Accelerators (ECFA) is now preparing for an LHC Workshop to be held in Aachen from 4-9 October. ; An important milestone for the HERA electron-proton collider being built at the German DESY Laboratory in Hamburg was passed early in April when the turbines of the HERA refrigeration plant were switched on to cool down the first octant of the superconducting proton ring.

10th joint CERN-Fermilab Hadron Collider Physics Summer School

CERN Document Server

2015-01-01

The CERN-Fermilab Hadron Collider Physics Summer Schools are targeted particularly at young postdocs and senior PhD students working towards the completion of ther thesis project, in both experimental High Energy Physics (HEP) and phenomenology.

CERN accelerator school: Antiprotons for colliding beam facilities

International Nuclear Information System (INIS)

Bryant, P.; Newman, S.

1984-01-01

This is a specialized course which addresses a wide spectrum of theoretical and technological problems confronting the designer of an antiproton facility for high-energy-physics research. A broad and profound basis is provided by the lecturers' substantial experience gained over many years with CERN's unique equipment. Topics include beam optics, special lattices for antiproton accumulation and storage rings, antiproton production, stochastic cooling, acceleration and storage, r.f. noise, r.f. beam manipulations, beam-beam interaction, beam stability due to ion accumulation, and diagnostics. The SPS (Super Proton Synchrotron) panti p collider, LEAR (the Low Energy Antiproton Ring at CERN), antiprotons in the ISR (Intersecting Storage Rings), the new antiproton collector (ACOL) and gas jet targets are also discussed. A table is included listing the parameters of all CERN's accelerators and storage rings. See hints under the relevant topics. (orig./HSI)

Search for Exotic Processes at the CERN pp Collider

DEFF Research Database (Denmark)

Ansari, R.; Bagnaia, P.; Banner, M.;......Kofoed-Hansen

1987-01-01

The total UA2 data sample at the CERN pp̄ Collider corresponds to an integrated luminosity of 910 nb−1. Limits on various hypothetical processes, such as production of excited electrons, additional charged or neutral vector bosons, or supersymmetric particles, are presented from the analysis...

Super High Energy Colliding Beam Accelerators

International Nuclear Information System (INIS)

Abdelaziz, M.E.

2009-01-01

This lecture presents a review of cyclic accelerators and their energy limitations. A description is given of the phase stability principle and evolution of the synchrotron, an accelerator without energy limitation. Then the concept of colliding beams emerged to yield doubling of the beam energy as in the Tevatron 2 trillion electron volts (TeV) proton collider at Fermilab and the Large Hadron Collider (LHC) which is now planned as a 14-TeV machine in the 27 kilometer tunnel of the Large Electron Positron (LEP) collider at CERN. Then presentation is given of the Superconducting Supercollider (SSC), a giant accelerator complex with energy 40-TeV in a tunnel 87 kilometers in circumference under the country surrounding Waxahachie in Texas, U.S.A. These superhigh energy accelerators are intended to smash protons against protons at energy sufficient to reveal the nature of matter and to consolidate the prevailing general theory of elementary particle.

The new generation of PowerPC VMEbus front end computers for the CERN SPS and LEP accelerators control system

OpenAIRE

Van den Eynden, M

1995-01-01

The CERN SPS and LEP PowerPC project is aimed at introducing a new generation of PowerPC VMEbus processor modules running the LynxOS real-time operating system. This new generation of front end computers using the state-of-the-art microprocessor technology will first replace the obsolete Xenix PC based systems (about 140 installations) successfully used since 1988 to control the LEP accelerator. The major issues addressed in the scope of this large scale project are the technical specificatio...

CERN: LHC progress

International Nuclear Information System (INIS)

Anon.

1993-01-01

The push for CERN's next major project, the LHC proton collider to be built in the 27-kilometre LEP tunnel, is advancing on a wide front. For the machine itself, there has been considerable progress in the detailed design. While the main thrust is for proton-proton collisions, heavy ions are also on the LHC collision menu. On the experimental side, proposals are coming into sharper focus. For the machine, the main aim is for the highest possible proton collision energies and collision rates in the confines of the existing LEP tunnel, and the original base design looked to achieve these goals in three collision regions. Early discussions on the experimental programme quickly established that the most probable configuration would have two collision regions rather than three. This, combined with hints that the electronics of several detectors would have to handle several bunch crossings at a time, raised the question whether the originally specified bunch spacing of 15 ns was still optimal

High accuracy magnetic field mapping of the LEP spectrometer magnet

CERN Document Server

Roncarolo, F

2000-01-01

The Large Electron Positron accelerator (LEP) is a storage ring which has been operated since 1989 at the European Laboratory for Particle Physics (CERN), located in the Geneva area. It is intended to experimentally verify the Standard Model theory and in particular to detect with high accuracy the mass of the electro-weak force bosons. Electrons and positrons are accelerated inside the LEP ring in opposite directions and forced to collide at four locations, once they reach an energy high enough for the experimental purposes. During head-to-head collisions the leptons loose all their energy and a huge amount of energy is concentrated in a small region. In this condition the energy is quickly converted in other particles which tend to go away from the interaction point. The higher the energy of the leptons before the collisions, the higher the mass of the particles that can escape. At LEP four large experimental detectors are accommodated. All detectors are multi purpose detectors covering a solid angle of alm...

Collide@CERN is looking for mentors

CERN Multimedia

2011-01-01

The Collide@CERN Artist-in-Residence Programme is currently seeking CERN scientists interested in engaging in thought-provoking and creative collaborations with visiting artists.     In early 2012, a Digital artist will take up a 2-month residency and a Dance and Performance artist a 3-month residency.  Each artist will be allocated a specially selected science inspiration partner to work with. Both the artists and their mentors will give a public lecture in the Globe of Science and Innovation at the beginning and end of the residencies.  One scientist will be selected for each artist. Mentors and artists will be required to share knowledge by:   ·      Meeting once a week throughout the residency ·      Conducting online communications (such as a blog). If you are interested in becoming a mentor, please send the following information by e-m...

Investigation of induced radioactivity in the CERN Large Electron Positron collider for its decommissioning

CERN Document Server

Silari, Marco

2004-01-01

The future installation of the Large Hadron Collider in the tunnel formerly housing the Large Electron Positron collider (LEP) required the dismantling of the latter after 11-year operation. As required by the French legislation, an extensive theoretical study was conducted before decommissioning to establish the possible activation paths both in the accelerator and in the four experiments (L3, ALEPH, OPAL and DELPHI) installed around the ring. The aim was to define which areas may contain activated material and which ones would be completely free of activation. The four major sources of activation in LEP, i.e., distributed and localized beam losses, synchrotron radiation and the super-conducting RF cavities, were investigated. Conversion coefficients from unit lost beam power to induced specific activity were established for a number of materials. A similar study was conducted for the four experiments, evaluating the four potential sources of induced radioactivity, namely e**+e **- annihilation events, two-p...

Cooperation Agreement between the Government of Australia and the European Orgaization for Nuclear Research (CERN) concerning the further development of scientific and technical co-operation in the research projects of CERN Ministry - Regulatory Decree No 3/92 of 6 March

International Nuclear Information System (INIS)

1991-01-01

The agreement provides for co-operation on research projects. Australian specialists may participate in CERN research projects, in particular in connection with the Large Electron-Position Collider-LEP. The Agreement entered into force on the date of its signature for an initial period of five years and is renewable. (NEA)

Electroweak Measurements in Electron-Positron Collisions at W-Boson-Pair Energies at LEP

CERN Document Server

Schael, S.; Bruneliere, R.; Buskulic, D.; De Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Jezequel, S.; Lees, J.P.; Lucotte, A.; Martin, F.; Merle, E.; Minard, M.N.; Nief, J.Y.; Odier, P.; Pietrzyk, B.; Trocme, B.; Bravo, S.; Casado, M.P.; Chmeissani, M.; Comas, P.; Crespo, J.M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Grauges, E.; Juste, A.; Martinez, M.; Merino, G.; Miquel, R.; Mir, Ll. M.; Orteu, S.; Pacheco, A.; Park, I.C.; Perlas, J.; Riu, I.; Ruiz, H.; Sanchez, F.; Colaleo, A.; Creanza, D.; De Filippis, N.; De Palma, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Bazarko, A.; Becker, U.; Boix, G.; Bird, F.; Blucher, E.; Bonvicini, B.; Bright-Thomas, P.; Barklow, T.; Buchmuller, O.; Cattaneo, M.; Cerutti, F.; Ciulli, V.; Clerbaux, B.; Drevermann, H.; Forty, R.W.; Frank, M.; Greening, T.C.; Hagelberg, R.; Halley, A.W.; Gianotti, F.; Girone, M.; Hansen, J.B.; Harvey, J.; Jacobsen, R.; Hutchcroft, D.E.; Janot, P.; Jost, B.; Knobloch, J.; Kado, M.; Lehraus, I.; Lazeyras, P.; Maley, P.; Mato, P.; May, J.; Moutoussi, A.; Pepe-Altarelli, M.; Ranjard, F.; Rolandi, L.; Schlatter, D.; Schmitt, B.; Schneider, O.; Tejessy, W.; Teubert, F.; Tomalin, I.R.; Tournefier, E.; Veenhof, R.; Valassi, A.; Wiedenmann, W.; Wright, A.E.; Ajaltouni, Z.; Badaud, F.; Chazelle, G.; Deschamps, O.; Dessagne, S.; Falvard, A.; Ferdi, C.; Fayolle, D.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.C.; Pallin, D.; Pascolo, J.M.; Perret, P.; Podlyski, F.; Bertelsen, H.; Fernley, T.; Hansen, J.D.; Hansen, J.R.; Hansen, P.H.; Kraan, A.C.; Lindahl, A.; Mollerud, R.; Nilsson, B.S.; Rensch, B.; Waananen, A.; Daskalakis, G.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J.C.; Machefert, F.; Rouge, A.; Rumpf, M.; Swynghedauw, M.; Tanaka, R.; Verderi, M.; Videau, H.; Ciulli, V.; Focardi, E.; Parrini, G.; Zachariadou, K.; Corden, M.; Georgiopoulos, C.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Cerutti, F.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, G.P.; Passalacqua, L.; Picchi, P.; Colrain, P.; ten Have, I.; Hughes, I.S.; Kennedy, J.; Knowles, I.G.; Lynch, J.G.; Morton, W.T.; Negus, P.; O'Shea, V.; Raine, C.; Reeves, P.; Scarr, J.M.; Smith, K.; Thompson, A.S.; Turnbull, R.M.; Wasserbaech, S.; Buchmuller, O.; Cavanaugh, R.; Dhamotharan, S.; Geweniger, C.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E.E.; Putzer, A.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, W.; Wunsch, M.; Beuselinck, R.; Binnie, D.M.; Cameron, W.; Davies, G.; Dornan, P.J.; Goodsir, S.; Marinelli, N.; Martin, E.B.; Nash, J.; Nowell, J.; Rutherford, S.A.; Sedgbeer, J.K.; Thompson, J.C.; White, R.; Williams, M.D.; Ghete, V.M.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bouhova-Thacker, E.; Bowdery, C.K.; Buck, P.G.; Clarke, D.P.; Ellis, G.; Finch, A.J.; Foster, F.; Hughes, G.; Jones, R.W.L.; Keemer, N.R.; Pearson, M.R.; Robertson, N.A.; Sloan, T.; Smizanska, M.; Snow, S.W.; Williams, M.I.; van der Aa, O.; Delaere, C.; Leibenguth, G.; Lemaitre, V.; Bauerdick, L.A.T.; Blumenschein, U.; van Gemmeren, P.; Giehl, I.; Holldorfer, F.; Jakobs, K.; Kasemann, M.; Kayser, F.; Kleinknecht, K.; Muller, A.S.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.G.; Schmeling, S.; Wachsmuth, H.; Wanke, R.; Zeitnitz, C.; Ziegler, T.; Aubert, J.J.; Benchouk, C.; Bonissent, A.; Carr, J.; Coyle, P.; Curtil, C.; Ealet, A.; Etienne, F.; Fouchez, D.; Motsch, F.; Payre, P.; Rousseau, D.; Tilquin, A.; Talby, M.; Thulasidas, M.; Aleppo, M.; Antonelli, M.; Ragusa, F.; Buscher, V.; David, A.; Dietl, H.; Ganis, G.; Huttmann, K.; Lutjens, G.; Mannert, C.; Manner, W.; Moser, H.G.; Settles, R.; Seywerd, H.; Stenzel, H.; Villegas, M.; Wiedenmann, W.; Wolf, G.; Azzurri, P.; Boucrot, J.; Callot, O.; Chen, S.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.F.; Heusse, Ph.; Jacholkowska, A.; Le Diberder, F.; Lefrancois, J.; Mutz, A.M.; Schune, M.H.; Serin, L.; Veillet, J.J.; Videau, I.; Zerwas, D.; Azzurri, P.; Bagliesi, G.; Bettarini, S.; Boccali, T.; Bozzi, C.; Calderini, G.; Dell'Orso, R.; Fantechi, R.; Ferrante, I.; Fidecaro, F.; Foa, L.; Giammanco, A.; Giassi, A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P.S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Sciaba, A.; Sguazzoni, G.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Vannini, C.; Venturi, A.; Verdini, P.G.; Awunor, O.; Blair, G.A.; Cowan, G.; Garcia-Bellido, A.; Green, M.G.; Medcalf, T.; Misiejuk, A.; Strong, J.A.; Teixeira-Dias, P.; Botterill, D.R.; Clifft, R.W.; Edgecock, T.R.; Edwards, M.; Haywood, S.J.; Norton, P.R.; Tomalin, I.R.; Ward, J.J.; Bloch-Devaux, B.; Boumediene, D.; Colas, P.; Emery, S.; Fabbro, B.; Kozanecki, W.; Lancon, E.; Lemaire, M.C.; Locci, E.; Perez, P.; Rander, J.; Renardy, J.F.; Roussarie, A.; Schuller, J.P.; Schwindling, J.; Tuchming, B.; Vallage, B.; Black, S.N.; Dann, J.H.; Kim, H.Y.; Konstantinidis, N.; Litke, A.M.; McNeil, M.A.; Taylor, G.; Booth, C.N.; Cartwright, S.; Combley, F.; Hodgson, P.N.; Lehto, M.; Thompson, L.F.; Affholderbach, K.; Barberio, E.; Bohrer, A.; Brandt, S.; Burkhardt, H.; Feigl, E.; Grupen, C.; Hess, J.; Lutters, G.; Meinhard, H.; Minguet-Rodriguez, J.; Mirabito, L.; Misiejuk, A.; Neugebauer, E.; Ngac, A.; Prange, G.; Rivera, F.; Saraiva, P.; Schafer, U.; Sieler, U.; Smolik, L.; Stephan, F.; Trier, H.; Apollonio, M.; Borean, C.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Pitis, L.; He, H.; Kim, H.; Putz, J.; Rothberg, J.; Armstrong, S.R.; Bellantoni, L.; Berkelman, K.; Cinabro, D.; Conway, J.S.; Cranmer, K.; Elmer, P.; Feng, Z.; Ferguson, D.P.S.; Gao, Y.; Gonzalez, S.; Grahl, J.; Harton, J.L.; Hayes, O.J.; Hu, H.; Jin, S.; Johnson, R.P.; Kile, J.; McNamara, P.A., III; Nielsen, J.; Orejudos, W.; Pan, Y.B.; Saadi, Y.; Scott, I.J.; Sharma, V.; Walsh, A.M.; Walsh, J.; Wear, J.; von Wimmersperg-Toeller, J.H.; Wiedenmann, W.; Wu, J.; Wu, S.L.; Wu, X.; Yamartino, J.M.; Zobernig, G.; Dissertori, G.; Abdallah, J.; Abreu, P.; Adam, W.; Adzic, P.; Albrecht, T.; Alemany-Fernandez, R.; Allmendinger, T.; Allport, P.P.; Amaldi, U.; Amapane, N.; Amato, S.; Anashkin, E.; Andreazza, A.; Andringa, S.; Anjos, N.; Antilogus, P.; Apel, W-D.; Arnoud, Y.; Ask, S.; Asman, B.; Augustin, J.E.; Augustinus, A.; Baillon, P.; Ballestrero, A.; Bambade, P.; Barbier, R.; Bardin, D.; Barker, G.J.; Baroncelli, A.; Battaglia, M.; Baubillier, M.; Becks, K-H.; Begalli, M.; Behrmann, A.; Belous, K.; Ben-Haim, E.; Benekos, N.; Benvenuti, A.; Berat, C.; Berggren, M.; Berntzon, L.; Bertrand, D.; Besancon, M.; Besson, N.; Bloch, D.; Blom, M.; Bluj, M.; Bonesini, M.; Boonekamp, M.; Booth, P.S.L.; Borisov, G.; Botner, O.; Bouquet, B.; Bowcock, T.J.V.; Boyko, I.; Bracko, M.; Brenner, R.; Brodet, E.; Bruckman, P.; Brunet, J.M.; Bugge, L.; Buschbeck, B.; Buschmann, P.; Calvi, M.; Camporesi, T.; Canale, V.; Carena, F.; Castro, N.; Cavallo, F.; Chapkin, M.; Charpentier, Ph.; Checchia, P.; Chierici, R.; Chliapnikov, P.; Chudoba, J.; Cieslik, K.; Collins, P.; Contri, R.; Cosme, G.; Cossutti, F.; Costa, M.J.; Crawley, B.; Crennell, D.; Cuevas, J.; D'Hondt, J.; Dalmau, J.; da Silva, T.; Da Silva, W.; Della Ricca, G.; De Angelis, A.; De Boer, W.; De Clercq, C.; De Lotto, B.; De Maria, N.; De Min, A.; De Paula, L.; Di Ciaccio, L.; Di Simone, A.; Doroba, K.; Drees, J.; Dris, M.; Duperrin, A.; Eigen, G.; Ekelof, T.; Ellert, M.; Elsing, M.; Espirito Santo, M.C.; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Fernandez, J.; Ferrer, A.; Ferro, F.; Flagmeyer, U.; Foeth, H.; Fokitis, E.; Fulda-Quenzer, F.; Fuster, J.; Gandelman, M.; Garcia, C.; Gavillet, Ph.; Gazis, E.; Gele, D.; Gokieli, R.; Golob, B.; Gomez-Ceballos, G.; Goncalves, P.; Graziani, E.; Grosdidier, G.; Grzelak, K.; Guy, J.; Haag, C.; Hallgren, A.; Hamacher, K.; Hamilton, K.; Haug, S.; Hauler, F.; Hedberg, V.; Hennecke, M.; Herr, H.; Hoffman, J.; Holmgren, S-O.; Holt, P.J.; Houlden, M.A.; Hultqvist, K.; Jackson, J.N.; Jarlskog, G.; Jarry, P.; Jeans, D.; Johansson, E.K.; Johansson, P.D.; Jonsson, P.; Joram, C.; Jungermann, L.; Kapusta, F.; Katsanevas, S.; Katsoufis, E.; Kernel, G.; Kersevan, B.P.; Kerzel, U.; Kiiskinen, A.; King, B.T.; Kjaer, N.J.; Kluit, P.; Kokkinias, P.; Kostioukhine, V.; Kourkoumelis, C.; Kouznetsov, O.; Krumstein, Z.; Kucharczyk, M.; Lamsa, J.; Leder, G.; Ledroit, F.; Leinonen, L.; Leitner, R.; Lemonne, J.; Lepeltier, V.; Lesiak, T.; Libby, J.; Liebig, W.; Liko, D.; Lipniacka, A.; Lopes, J.H.; Lopez, J.M.; Loukas, D.; Lutz, P.; Lyons, L.; MacNaughton, J.; Malek, A.; Maltezos, S.; Mandl, F.; Marco, J.; Marco, R.; Marechal, B.; Margoni, M.; Marin, J-C.; Mariotti, C.; Markou, A.; Martinez-Rivero, C.; Masik, J.; Mastroyiannopoulos, N.; Matorras, F.; Matteuzzi, C.; Mazzucato, F.; Mazzucato, M.; Nulty, R.Mc; Meroni, C.; Meyer, W.T.; Migliore, E.; Mitaroff, W.; Mjoernmark, U.; Moa, T.; Moch, M.; Moenig, K.; Monge, R.; Montenegro, J.; Moraes, D.; Morettini, P.; Mueller, U.; Muenich, K.; Mulders, M.; Mundim, L.; Murray, W.; Muryn, B.; Myatt, G.; Myklebust, T.; Nassiakou, M.; Navarria, F.; Nawrocki, K.; Nemecek, S.; Nicolaidou, R.; Nikolaenko, V.; Nikolenko, M.; Oblakowska-Mucha, A.; Obraztsov, V.; Olshevski, A.; Onofre, A.; Orava, R.; Osterberg, K.; Ouraou, A.; Oyanguren, A.; Paganoni, M.; Paiano, S.; Palacios, J.P.; Palka, H.; Papadopoulou, Th. D.; Pape, L.; Parkes, C.; Parodi, F.; Parzefall, U.; Passeri, A.; Passon, O.; Perepelitsa, V.; Perrotta, A.; Petrolini, A.; Piedra, J.; Pieri, L.; Pierre, F.; Pimenta, M.; Podobnik, T.; Poireau, V.; Pol, M.E.; Polok, G.; Poropat, P.; Pozdniakov, V.; Pukhaeva, N.; Pullia, A.; Radojicic, D.; Rames, J.; Ramler, L.; Read, A.; Rebecchi, P.; Rehn, J.; Reid, D.; Reinhardt, R.; Renton, P.; Richard, F.; Ridky, J.; Ripp-Baudot, I.; Rivero, M.; Rodriguez, D.; Romero, A.; Ronchese, P.; Rosenberg, E.; Roudeau, P.; Rovelli, T.; Ruhlmann-Kleider, V.; Ryabtchikov, D.; Sadovsky, A.; Salmi, L.; Salt, J.; Sander, C.; Savoy-Navarro, A.; Schwickerath, U.; Segar, A.; Sekulin, R.; Siebel, M.; Simard, L.; Sisakian, A.; Smadja, G.; Smirnova, O.; Sokolov, A.; Sopczak, A.; Sosnowski, R.; Spassov, T.; Stanitzki, M.; Stocchi, A.; Strauss, J.; Stugu, B.; Szczekowski, M.; Szeptycka, M.; Szumlak, T.; Tabarelli, T.; Taffard, A.C.; Tegenfeldt, F.; Terranova, F.; Thomas, J.; Timmermans, J.; Tkatchev, L.; Tobin, M.; Todorovova, S.; Tome, B.; Tonazzo, A.; Tortosa, P.; Travnicek, P.; Treille, D.; Tristram, G.; Trochimczuk, M.; Troncon, C.; Turluer, M-L.; Tyapkin, I.A.; Tyapkin, P.; Tzamarias, S.; Uvarov, V.; Valenti, G.; Van Dam, P.; Van Eldik, J.; Van Lysebetten, A.; van Remortel, N.; Van Vulpen, I.; Vegni, G.; Veloso, F.; Venus, W.; Verbeure, F.; Verdier, P.; Verzi, V.; Vilanova, D.; Vitale, L.; Vrba, V.; Wahlen, H.; Washbrook, A.J.; Weiser, C.; Wicke, D.; Wickens, J.; Wilkinson, G.; Winter, M.; Witek, M.; Yushchenko, O.; Zalewska, A.; Zalewski, P.; Zavrtanik, D.; Zhuravlov, V.; Zimine, N.I.; Zintchenko, A.; Achard, P.; Adriani, O.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, V.P.; Anselmo, F.; Arefiev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; De Asmundis, R.; D'eglon, P.; Debreczeni, J.; Degre, A.; Dehmelt, K.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duda, M.; Echenard, B.; Eline, A.; El Hage, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Yu.; Ganguli, S.N.; Garcia-Abia, P.; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, G.; Grimm, O.; Gruenewald, M.W.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, A.; Hirschfelder, J.; Hofer, H.; Hohlmann, M.; Holzner, G.; Hou, S.R.; Jin, B.N.; Jindal, P.; Jones, L.W.; de Jong, P.; Josa-Mutuberria, I.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, J.; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Le Goff, J.M.; Leiste, R.; Levtchenko, M.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Luci, C.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musy, M.; Nagy, S.; Natale, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Nisati, A.; Novak, T.; Nowak, H.; Ofierzynski, R.; Organtini, G.; Palomares, C.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, T.; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Piccolo, D.; Pierella, F.; Pieri, M.; Pioppi, M.; Pirou'e, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Pothier, J.; Prokofiev, D.; Rahal-Callot, G.; Rahaman, M.A.; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Rembeczki, S.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, K.; Roe, B.P.; Romero, L.; Rosca, A.; Rosemann, C.; Rosenbleck, C.; Rosier-Lees, S.; Roth, S.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Schafer, C.; Schegelsky, V.; Schopper, H.; Schotanus, D.J.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Son, D.; Souga, C.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, C.; Ting, S.C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Vasquez, R.; Vesztergombi, G.; Vetlitsky, I.; Viertel, G.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobiev, I.; Vorobyov, A.A.; Wadhwa, M.; Wang, Q.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, An.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zimmermann, B.; Zoller, M.; Abbiendi, G.; Ackerstaff, K.; Ainsley, C.; Akesson, P.F.; Alexander, G.; Allison, J.; Altekamp, N.; Ametewee, K.; Anagnostou, G.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Bartoldus, R.; Batley, R.J.; Baumann, S.; Bechtle, P.; Bechtluft, J.; Beeston, C.; Behnke, T.; Bell, K.W.; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bentvelsen, S.; Berlich, P.; Bethke, S.; Biebel, O.; Boeriu, O.; Blobel, V.; Bloodworth, I.J.; Bloomer, J.E.; Bobinski, M.; Bock, P.; Bonacorsi, D.; Bosch, H.M.; Boutemeur, M.; Bouwens, B.T.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, R.M.; Burckhart, H.J.; Burgard, C.; Burgin, R.; Cammin, J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couchman, J.; Couyoumtzelis, C.; Coxe, R.L.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallapiccola, C.; Dallavalle, M.; Dallison, S.; de Jong, S.; De Roeck, A.; Dervan, P.; De Wolf, E.A.; del Pozo, L.A.; Desch, K.; Dienes, B.; Dixit, M.S.; do Couto e Silva, E.; Donkers, M.; Doucet, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Edwards, J.E.G.; Estabrooks, P.G.; Etzion, E.; Evans, H.G.; Evans, M.; Fabbri, F.; Fanti, M.; Fath, P.; Feld, L.; Ferrari, P.; Fiedler, F.; Fierro, M.; Fischer, H.M.; Fleck, I.; Folman, R.; Fong, D.G.; Ford, M.; Foucher, M.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gascon-Shotkin, S.M.; Gaycken, G.; Geddes, N.I.; Geich-Gimbel, C.; Geralis, T.; Giacomelli, G.; Giacomelli, P.; Giacomelli, R.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Giunta, M.; Glenzinski, D.; Goldberg, J.; Goodrick, M.J.; Gorn, W.; Graham, K.; 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Koetke, D.S.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, R.V.; Kramer, T.; Krasznahorkay, A., Jr.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Kyberd, P.; Lafferty, G.D.; Lahmann, R.; Lai, W.P.; Landsman, H.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lazic, D.; Lee, A.M.; Lefebvre, E.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Lewis, C.; Liebisch, R.; Lillich, J.; List, B.; List, J.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, A.; Ludwig, J.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Marchant, T.E.; Markus, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Matthews, W.; Mattig, P.; McDonald, W.J.; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McNab, A.I.; McPherson, R.A.; Mendez-Lorenzo, P.; Meijers, F.; Menges, W.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, N.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Morii, M.; Muller, U.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nellen, B.; Nijjhar, B.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oh, A.; Okpara, A.; Oldershaw, N.J.; Omori, T.; Oreglia, M.J.; Orito, S.; Pahl, C.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Pearce, M.J.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, D.E.; Poffenberger, P.; Polok, J.; Poli, B.; Pooth, O.; Posthaus, A.; Przybycien, M.; Przysiezniak, H.; Quadt, A.; Rabbertz, K.; Rees, D.L.; Rembser, C.; Renkel, P.; Rick, H.; Rigby, D.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rooke, A.; Ros, E.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rosvick, M.; Routenburg, P.; Rozen, Y.; Runge, K.; Runolfsson, O.; Ruppel, U.; Rust, D.R.; Rylko, R.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisyan, E.K.G.; Sasaki, M.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schenk, P.; Schieck, J.; Schmitt, S.; Schorner-Sadenius, T.; Schroder, M.; Schultz-Coulon, H.C.; Schulz, M.; Schumacher, M.; Schutz, P.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skillman, A.; Skuja, A.; Smith, A.M.; Smith, T.J.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Spano, F.; Springer, R.W.; Sproston, M.; Stahl, A.; Steiert, M.; Stephens, K.; Steuerer, J.; Stockhausen, B.; Stoll, K.; Strom, D.; Strohmer, R.; Strumia, F.; Stumpf, L.; Surrow, B.; Szymanski, P.; Tafirout, R.; Talbot, S.D.; Tanaka, S.; Taras, P.; Tarem, S.; Taylor, R.J.; Tasevsky, M.; Teuscher, R.; Thiergen, M.; Thomas, J.; Thomson, M.A.; von Torne, E.; Torrence, E.; Towers, S.; Toya, D.; Trefzger, T.; Trigger, I.; Trocsanyi, Z.; Tsukamoto, T.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Utzat, P.; Vachon, B.; Van Kooten, R.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Vikas, P.; Vincter, M.; Vokurka, E.H.; Vollmer, C.F.; Voss, H.; Vossebeld, J.; Wackerle, F.; Wagner, A.; Waller, D.; Ward, C.P.; Ward, D.R.; Ward, J.J.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; White, J.S.; Wilkens, B.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wotton, S.; Wyatt, T.R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.; Zivkovic, L.

2013-01-01

Electroweak measurements performed with data taken at the electron-positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3~fb$^{-1}$ collected by the four LEP experiments ALEPH, DELPHI, L3 and OPAL, at centre-of-mass energies ranging from $130~GeV$ to $209~GeV$. Combining the published results of the four LEP experiments, the measurements include total and differential cross-sections in photon-pair, fermion-pair and four-fermion production, the latter resulting from both double-resonant WW and ZZ production as well as singly resonant production. Total and differential cross-sections are measured precisely, providing a stringent test of the Standard Model at centre-of-mass energies never explored before in electron-positron collisions. Final-state interaction effects in four-fermion production, such as those arising from colour reconnection and Bose-Einstein correlations between the two W decay systems arising ...

EIB lends EUR 300 million for CERN's major collider

CERN Multimedia

2002-01-01

"The European Investment Bank (EIB) is lending EUR 300 million to finance the final phase of construction of the Large Hadron Collider (LHC) at CERN, the European Organization for Nuclear Research. The EIB loan will also help to finance the instrumentation to record and analyse the high-energy particle collisions at the LHC" (1 page).

People and things. CERN Courier, March 1980, v. 20(1)

International Nuclear Information System (INIS)

Anon.

1980-01-01

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events, like the Europhysics Study Conference on the Unification of Fundamental Interactions in Sicily, or the International Conference on Experimentation at LEP in Uppsala. In other news it has been decided at the Stanford Linear Accelerator Center to put money into research and development for the Single Pass Collider Project

CERN prepares for the LHC and beyond

Energy Technology Data Exchange (ETDEWEB)

Rodgers, Peter

2000-05-01

The phrase ''needle in a haystack'' - the challenge of finding something small but important in the midst of a much, much larger object - is often used to describe CERN. It could be applied to searching for someone's office in one of the 373 buildings that occupy the laboratory's site at Meyrin, just outside Geneva on the Swiss rench border, but the real needle in the haystack at CERN is the Higgs boson. The Higgs is the particle that is responsible for other fundamental particles such as quarks and Z-bosons having mass. It is also the main reason that CERN is building a machine called the Large Hadron Collider (LHC) at a cost of SwFr 2bn. Particles predicted by supersymmetry the theory that every particle has a supersymmetric partner with the same mass and charge but different ''spin'' are the other top priority. There is a chance, albeit it a small one, that particle physicists might find the Higgs boson at CERN's large electron positron (LEP) collider before it is shut down to make way for the LHC. It all depends on how high the beam energy at LEP which currently stands at 103 GeV (103 X 109 electron volts) can be raised. ''1 GeV can matter at this stage'', says Luciano Maiani, the lab's director general. ''Exploring up to a mass of 114 GeV is optimistic but not impossible. Unless we see the Higgs, the current plan is for LEP to be dismantled after it stops running at the end of September. Installation of the LHC in the LEP tunnel will then start in October.'' The LHC will collide protons at a centre-of-mass energy of 14 TeV (14 000 GeV), and two massive general-purpose detectors ATLAS and CMS will search for evidence of the Higgs and supersymmetry. A third experiment called LHC-b will probe the difference between matter and antimatter, while the ALICE experiment will study the extreme state of matter known as the quark gluon plasma. Meanwhile, two massive teams

The LEP physics program

International Nuclear Information System (INIS)

Davier, M.

1985-06-01

The physics program of LEP is reviewed in the context of recent developments from the SpantipS collider. LEP offers the unique possibility to unambiguously explore the particle spectrum up to a mass of 100 GeV i.e. over the mass range typical of the electroweak symmetry breaking. 31 refs.

submitter Projects for ultra-high-energy circular colliders at CERN

CERN Document Server

Bogomyagkov, A V; Levichev, E B; Piminov, P A; Sinyatkin, S V; Shatilov, D N; Benedict, M; Oide, K; Zimmermann, F

2016-01-01

Within the Future Circular Collider (FCC) design study launched at CERN in 2014, it is envisaged to construct hadron (FCC-hh) and lepton (FCC-ee) ultra-high-energy machines aimed to replace the LHC upon the conclusion of its research program. The Budker Institute of Nuclear Physics is actively involved in the development of the FCC-ee electron–positron collider. The Crab Waist (CR) scheme of the collision region that has been proposed by INP and will be implemented at FCC-ee is expected to provide high luminosity over a broad energy range. The status and development of the FCC project are described, and its parameters and limitations are discussed for the lepton collider in particular.

The LEP program

International Nuclear Information System (INIS)

Allaby, J.V.

1986-01-01

Details of the LEP program are discussed in this paper. LEP is an electron-positron collider 26 kms in circumference. At present, four interaction regions are to be equipped with experiments, although there is the potential for eight crossing points with four-bunch operation. Before reviewing the experiments, some basic facts about LEP are recalled. The collider is located underground between the outskirts of Geneva and the Jura mountains. The major part of the tunnel in which LEP will be installed will be bored by machine in the ''molasse'' (a kind of sandstone) that lies at depths of several tens of meters below the surface of the ground in this region, which is formed of glacial moraine. However, about one-eighth of the circumference lies under the foothills of the Jura and here the tunnel must pass through the limestone rock where a boring machine cannot be used. Since the surface of the ground is itself not flat over this huge area, the plane of the machine is not horizontal, but slightly inclined to minimize the distance from the surface to the interaction regions; hence, the cost of the access shafts

People and things. CERN Courier, May 1990, v.30(4)

International Nuclear Information System (INIS)

Anon.

1990-01-01

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events: ; Implications for 'dark matter' - the invisible mass of the Universe - were a talking point at the recent astrophysics workshop in the Moriond series, and a focus of the meeting 'LEP and the Universe' at CERN. ; This year's DESY Theory Workshop from 1-3 October will be on 'Waiting for the Top Quark'. ; To explore in detail and update the physics possibilities for the Large Hadron Collider (LHC) project at CERN, the European Committee for Future Accelerators (ECFA) is now preparing for an LHC Workshop to be held in Aachen from 4-9 October. ; An important milestone for the HERA electron-proton collider being built at the German DESY Laboratory in Hamburg was passed early in April when the turbines of the HERA refrigeration plant were switched on to cool down the first octant of the superconducting proton ring

Study of cosmic ray events with high muon multiplicity using the ALICE detector at the CERN Large Hadron Collider

CERN Document Server

Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahn, Sang Un; Aiola, Salvatore; Akindinov, Alexander; Alam, Sk Noor; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Millan Almaraz, Jesus Roberto; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Armesto Perez, Nestor; Arnaldi, Roberta; Arsene, Ionut Cristian; Arslandok, Mesut; Audurier, Benjamin; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Baldisseri, Alberto; Baltasar Dos Santos Pedrosa, Fernando; Baral, Rama Chandra; Barbano, Anastasia Maria; 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Kweon, Min Jung; Kwon, Youngil; La Pointe, Sarah Louise; La Rocca, Paola; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; Laudi, Elisa; Lea, Ramona; Leardini, Lucia; Lee, Graham Richard; Lee, Seongjoo; Legrand, Iosif; Lehas, Fatiha; Lemmon, Roy Crawford; Lenti, Vito; Leogrande, Emilia; Leon Monzon, Ildefonso; Leoncino, Marco; Levai, Peter; Li, Shuang; Li, Xiaomei; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Lonne, Per-Ivar; Loginov, Vitaly; Loizides, Constantinos; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lowe, Andrew John; Luettig, Philipp Johannes; Lunardon, Marcello; Luparello, Grazia; Ferreira Natal Da Luz, Pedro Hugo; Maevskaya, Alla; Mager, Magnus; Mahajan, Sanjay; Mahmood, Sohail Musa; Maire, Antonin; Majka, Richard Daniel; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manko, Vladislav; Manso, Franck; Manzari, Vito; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Margutti, Jacopo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martin, Nicole Alice; Martin Blanco, Javier; Martinengo, Paolo; Martinez Hernandez, Mario Ivan; Martinez-Garcia, Gines; Martinez Pedreira, Miguel; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Massacrier, Laure Marie; Mastroserio, Annalisa; Masui, Hiroshi; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel Anthony; Mazzoni, Alessandra Maria; Mcdonald, Daniel; Meddi, Franco; Melikyan, Yuri; Menchaca-Rocha, Arturo Alejandro; Meninno, Elisa; Mercado-Perez, Jorge; Meres, Michal; Miake, Yasuo; Mieskolainen, Matti Mikael; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Minervini, Lazzaro Manlio; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz Czeslaw; Mitra, Jubin; Mitu, Ciprian Mihai; Mohammadi, Naghmeh; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Montes Prado, Esther; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Perez Moreno, Luis Alberto; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhlheim, Daniel Michael; Muhuri, Sanjib; Mukherjee, Maitreyee; Mulligan, James Declan; Gameiro Munhoz, Marcelo; Munzer, Robert Helmut; Murray, Sean; Musa, Luciano; Musinsky, Jan; Naik, Bharati; Nair, Rahul; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Naru, Muhammad Umair; Nattrass, Christine; Nayak, Kishora; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Nellen, Lukas; Ng, Fabian; Nicassio, Maria; Niculescu, Mihai; Niedziela, Jeremi; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Cabanillas Noris, Juan Carlos; Norman, Jaime; Nyanin, Alexander; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Ohlson, Alice Elisabeth; Okatan, Ali; Okubo, Tsubasa; Olah, Laszlo; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Oliver, Michael Henry; Onderwaater, Jacobus; Oppedisano, Chiara; Orava, Risto; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozdemir, Mahmut; Pachmayer, Yvonne Chiara; Pagano, Paola; Paic, Guy; Pajares Vales, Carlos; Pal, Susanta Kumar; Pan, Jinjin; Pandey, Ashutosh Kumar; Pant, Divyash; Papcun, Peter; Papikyan, Vardanush; Pappalardo, Giuseppe; Pareek, Pooja; Park, Woojin; Parmar, Sonia; Passfeld, Annika; Paticchio, Vincenzo; Patra, Rajendra Nath; Paul, Biswarup; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitry Yurevich; Perez Lara, Carlos Eugenio; Perez Lezama, Edgar; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petrov, Viacheslav; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; 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Zardoshti, Nima; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Zhang, Zuman; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zyzak, Maksym

2016-01-19

ALICE is one of four large experiments at the CERN Large Hadron Collider near Geneva, specially designed to study particle production in ultra-relativistic heavy-ion collisions. Located 52 meters underground with 28 meters of overburden rock, it has also been used to detect muons produced by cosmic ray interactions in the upper atmosphere. In this paper, we present the multiplicity distribution of these atmospheric muons and its comparison with Monte Carlo simulations. This analysis exploits the large size and excellent tracking capability of the ALICE Time Projection Chamber. A special emphasis is given to the study of high multiplicity events containing more than 100 reconstructed muons and corresponding to a muon areal density $\\rho_{\\mu} > 5.9~$m$^{-2}$. Similar events have been studied in previous underground experiments such as ALEPH and DELPHI at LEP. While these experiments were able to reproduce the measured muon multiplicity distribution with Monte Carlo simulations at low and intermediate multiplic...

Physics at Future Colliders

CERN Document Server

Ellis, John R.

1999-01-01

After a brief review of the Big Issues in particle physics, we discuss the contributions to resolving that could be made by various planned and proposed future colliders. These include future runs of LEP and the Fermilab Tevatron collider, B factories, RHIC, the LHC, a linear electron-positron collider, an electron-proton collider in the LEP/LHC tunnel, a muon collider and a future larger hadron collider (FLHC). The Higgs boson and supersymmetry are used as benchmarks for assessing their capabilities. The LHC has great capacities for precision measurements as well as exploration, but also shortcomings where the complementary strengths of a linear electron-positron collider would be invaluable. It is not too soon to study seriously possible subsequent colliders.

Search for exotic processes at the CERN panti p collider

International Nuclear Information System (INIS)

Ansari, R.; Chollet, J.C.; Lotto, B. de; Fayard, L.; Froidevaux, D.; Gaillard, J.M.; Iconomidou-Fayard, L.; Merkel, B.; Moniez, M.; Parrour, G.; Repellin, J.P.; Sauvage, G.; Banner, M.; Lancon, E.; Loucatos, S.; Mansoulie, B.; Polverel, M.; Roussarie, A.; Ruhlmann, V.; Teiger, J.; Zaccone, H.; Battiston, R.; Mantovani, G.C.; Pepe, M.; Conta, C.; Ferrari, R.; Fraternali, M.; Goggi, V.G.; Livan, M.; Pastore, F.; Vercesi, V.; Dines-Hansen, J.; Hansen, P.; Kofoed-Hansen, O.; Madsen, B.; Mollerud, R.; Tsang, W.Y.

1987-01-01

The total UA2 data sample at the CERN panti p Collider corresponds to an integrated luminosity of 910 nb -1 . Limits on various hypothetical processes, such as production of excited electrons, additional charged or neutral vector bosons, or supersymmetric particles, are presented from the analysis of this sample. (orig.)

Measurement of the s dependence of jet production at the CERN pp collider

DEFF Research Database (Denmark)

Appel, J.A.; Bagnaia, P.; Banner, M.

1985-01-01

The production of very large transverse momentum (pT) hadron jets has been measured in the UA2 experiment at the CERN pp Collider for s=630 GeV. The inclusive jet production cross sections exhibit a pT-dependent increase with respect to the s=546 GeV data from previous Collider runs. This increase...

The DELPHI distributed information system for exchanging LEP machine related information

International Nuclear Information System (INIS)

Doenszelmann, M.; Gaspar, C.

1994-01-01

An information management system was designed and implemented to interchange information between the DELPHI experiment at CERN and the monitoring/control system for the LEP (Large Electron Positron Collider) accelerator. This system is distributed and communicates with many different sources and destinations (LEP) using different types of communication. The system itself communicates internally via a communication system based on a publish-and-subscribe mechanism, DIM (Distributed Information Manager). The information gathered by this system is used for on-line as well as off-line data analysis. Therefore it logs the information to a database and makes it available to operators and users via DUI (DELPHI User Interface). The latter was extended to be capable of displaying ''time-evolution'' plots. It also handles a protocol, implemented using a finite state machine, SMI (State Management Interface), for (semi-)automatic running of the Data Acquisition System and the Slow Controls System. ((orig.))

The transmission of accelerator timing information around CERN

International Nuclear Information System (INIS)

Beetham, C.G.; Kohler, K.; Parker, C.R.C.B.; Ribes, J.B.

1992-01-01

Prior to the construction of the Large Electron Positron (LEP) collider, machine timing information was transmitted around CERN's accelerators using a labyrinth of dedicated copper wires. However, at an early stage in the design of the LEP control system, it was decided to use an integrated communication system based on Time Division Multiplex (TDM) techniques. Therefore it was considered appropriate to use this facility to transmit timing information over long distances. This note describes the overall system, with emphasis placed on the connectivity requirements for the CCITT G.703 series of recommendations. In addition the methods used for error detection and correction, and also for redundancy, are described. The cost implications of using such a TDM based system are also analyzed. Finally the performance and reliability obtained by using this approach are discussed. (author)

Collide@CERN: exclusive open rehearsal of Gilles Jobin's last piece

CERN Multimedia

2012-01-01

Collide@CERN and Gilles Jobin, artist in residency at CERN, present an exclusive open rehearsal of his last piece SPIDER GALAXIES Tuesday 31 July 2012 - A new piece created to open new territories of the mind - Join us in Restaurant 1 from 4 p.m. (next to the Glass Box Restaurant) With this piece, the body turns into matter, which is complete, spatial and sensual. Come and see Gilles Jobin and his dancers. With a score by Cristian Vogel and Carla Scaletti invoking sound particles, while Daniel Demont disperses the spectrum. Protean, infinitely large or infinitesimal, such are the Spider Galaxies.    

Beyond the Large Hadron Collider: A First Look at Cryogenics for CERN Future Circular Colliders

Science.gov (United States)

Lebrun, Philippe; Tavian, Laurent

Following the first experimental discoveries at the Large Hadron Collider (LHC) and the recent update of the European strategy in particle physics, CERN has undertaken an international study of possible future circular colliders beyond the LHC. The study, conducted with the collaborative participation of interested institutes world-wide, considers several options for very high energy hadron-hadron, electron-positron and hadron-electron colliders to be installed in a quasi-circular underground tunnel in the Geneva basin, with a circumference of 80 km to 100 km. All these machines would make intensive use of advanced superconducting devices, i.e. high-field bending and focusing magnets and/or accelerating RF cavities, thus requiring large helium cryogenic systems operating at 4.5 K or below. Based on preliminary sets of parameters and layouts for the particle colliders under study, we discuss the main challenges of their cryogenic systems and present first estimates of the cryogenic refrigeration capacities required, with emphasis on the qualitative and quantitative steps to be accomplished with respect to the present state-of-the-art.

50 years of synchrotrons. Early synchrotrons in Britain, and early work for CERN. - The CERN synchrotrons. Lectures

International Nuclear Information System (INIS)

Lawson, J.; Brianti, G.

1997-01-01

In the first report, 'Early synchrotrons in Britain, and early work for CERN', John Lawson gives an extended account of the material presented at the John Adams lecture, and at the same time a revised and shortened version of RAL report 97-011, which contains fuller archival references and notes. During the period covered by this report there was extensive work in Russia, where the principle of phase stability had been discovered in 1944 by Veksler. Unfortunately, all experimental work was kept secret until Veksler's talk at the first 'Atoms for Peace' conference at Geneva in August 1955. In the second lecture, 'The CERN Synchrotrons', Giorgio Brianti outlines the history of alternating-gradient synchrotrons from 1953/54 until today. In preparing this lecture he was confronted with a vast amount of material, while the time at his disposal was not even one minute per year, implying a time compression factor close to one million. Therefore, he had to exercise drastic choices, which led him to concentrate on CERN hadron synchrotrons and colliders and leave aside the Large Electron-Positron storage ring (LEP). Indeed, LEP was the subject of the John Adams Memorial Lecture in 1990, and it may be treated again in the future in connection with its energy upgrade. Even with these severe limitations, it was impossible to do justice to the number and variety of events and to the ingenuity of the people who have carved the history of CERN and of particle physics on the magnets, radiofrequency cavities, vacuum etc., and on the record performance of our machines. (orig./WL)

American superconductor technology to help CERN to explore the mysteries of matter company's high temperature superconductor wire to be used in CERN's Large Hadron Collider

CERN Multimedia

2003-01-01

American Superconductor Corporation has been selected by CERN, to provide 14,000 meters of high temperature superconductor (HTS) wire for current lead devices that will be used in CERN's Large Hadron Collider (1 page).

Department of Energy assessment of the Large Hadron Collider

International Nuclear Information System (INIS)

1996-06-01

This report summarizes the conclusions of the committee that assessed the cost estimate for the Large Hadron Collider (LHC). This proton-proton collider will be built at CERN, the European Laboratory for Particle Physics near Geneva, Switzerland. The committee found the accelerator-project cost estimate of 2.3 billion in 1995 Swiss francs, or about $2 billion US, to be adequate and reasonable. The planned project completion date of 2005 also appears achievable, assuming the resources are available when needed. The cost estimate was made using established European accounting procedures. In particular, the cost estimate does not include R and D, prototyping and testing, spare parts, and most of the engineering labor. Also excluded are costs for decommissioning the Large Electron-Positron collider (LEP) that now occupies the tunnel, modifications to the injector system, the experimental areas, preoperations costs, and CERN manpower. All these items are assumed by CERN to be included in the normal annual operations budget rather than the construction budget. Finally, contingency is built into the base estimate, in contrast to Department of Energy (DOE) estimates that explicitly identify contingency. The committee's charge, given by Dr. James F. Decker, Deputy Directory of the DOE Office of Energy Research, was to understand the basis for the LHC cost estimate, identify uncertainties, and judge the overall validity of the estimate, proposed schedule, and related issues. The committee met at CERN April 22--26, 1996. The assessment was based on the October 1995 LHC Conceptual Design Report or ''Yellow Book,'' cost estimates and formal presentations made by the CERN staff, site inspection, detailed discussions with LHC technical experts, and the committee members' considerable experience

CERN prepares for the LHC and beyond

International Nuclear Information System (INIS)

Rodgers, Peter

2000-01-01

The phrase ''needle in a haystack'' - the challenge of finding something small but important in the midst of a much, much larger object - is often used to describe CERN. It could be applied to searching for someone's office in one of the 373 buildings that occupy the laboratory's site at Meyrin, just outside Geneva on the Swiss rench border, but the real needle in the haystack at CERN is the Higgs boson. The Higgs is the particle that is responsible for other fundamental particles such as quarks and Z-bosons having mass. It is also the main reason that CERN is building a machine called the Large Hadron Collider (LHC) at a cost of SwFr 2bn. Particles predicted by supersymmetry the theory that every particle has a supersymmetric partner with the same mass and charge but different ''spin'' are the other top priority. There is a chance, albeit it a small one, that particle physicists might find the Higgs boson at CERN's large electron positron (LEP) collider before it is shut down to make way for the LHC. It all depends on how high the beam energy at LEP which currently stands at 103 GeV (103 X 109 electron volts) can be raised. ''1 GeV can matter at this stage'', says Luciano Maiani, the lab's director general. ''Exploring up to a mass of 114 GeV is optimistic but not impossible. Unless we see the Higgs, the current plan is for LEP to be dismantled after it stops running at the end of September. Installation of the LHC in the LEP tunnel will then start in October.'' The LHC will collide protons at a centre-of-mass energy of 14 TeV (14 000 GeV), and two massive general-purpose detectors ATLAS and CMS will search for evidence of the Higgs and supersymmetry. A third experiment called LHC-b will probe the difference between matter and antimatter, while the ALICE experiment will study the extreme state of matter known as the quark gluon plasma. Meanwhile, two massive teams of physicists are preparing the two detectors for the LHC. Both ATLAS and CMS have the same basic

Comparison of impact-picture predictions with data from CERN panti p collider

International Nuclear Information System (INIS)

Bourrely, C.; Westfield Coll., London; Soffer, J.; Tai Tsun Wu.

1982-11-01

Recent data on the total cross section and the elastic slope parameters at small momentum transfers from the UA1 and UA4 Collaborations at the CERN panti p Collider are compared with the impact-picture predictions. (orig.)

CERN: Ten-Tesla twin

International Nuclear Information System (INIS)

Anon.

1991-01-01

An important step in the development of the high field superconducting magnets for CERN's proposed LHC proton collider came on 21 October when a 1 metre-long model of the proposed twin-dipole magnet produced a field of 10 Tesla in its two o beam apertures at the design temperature of 1.8K. The LHC designers have to plan for proton beams approaching 8 TeV to attain the right conditions for the quarks and gluons hidden deep inside protons to produce new physics. To contain these very high energy protons in the tight track of the 27-kilometre LEP tunnel would need the strongest magnetic bending power ever used in a full storage ring

Last LEP superconducting module travels to surface

CERN Multimedia

Patrice Loïez

2001-01-01

The last superconducting module is raised from the Large Electron-Positron (LEP) collider tunnel, through the main shaft, to the surface. Superconducting modules were only used in the LEP-2 phase of the accelerator, from 1996 to 2000.

The design and construction of a double-sided Silicon Microvertex Detector for the L3 experiment at CERN

International Nuclear Information System (INIS)

Adam, A.; Ambrosi, G.; Babucci, E.; Bertucci, B.; Biasini, M.; Bilei, G.M.; Caria, M.; Checcucci, B.; Easo, S.; Fiandrini, E.; Krastev, V.R.; Massetti, R.; Pauluzzi, M.; Santocchia, A.; Servoli, L.; Baschirotto, A.; Bosetti, M.; Pensotti, S.; Rancoita, P.G.; Rattaggi, M.; Terzi, G.; Battiston, R.; Bay, A.; Burger, W.J.; Extermann, P.; Perrin, E.; Susinno, G.F.; Bencze, G.Y.L.; Kornis, J.; Toth, J.; Bobbink, G.J.; Duinker, P.; Brooks, M.L.; Coan, T.E.; Kapustinsky, J.S.; Kinnison, W.W.; Lee, D.M.; Mills, G.B.; Thompson, T.C.; Busenitz, J.; DiBitonto, D.; Camps, C.; Commichau, V.; Hangartner, K.; Schmitz, P.; Chen, A.; Hou, S.; Lin, W.T.; Gougas, A.; Kim, D.; Paul, T.; Hauviller, C.; Herve, A.; Josa, I.; Landi, G.; Lebeau, M.; Lecomte, P.; Viertel, G.M.; Waldmeier, S.; Leiste, R.; Lejeune, E.; Weill, R.; Lohmann, W.; Nowak, H.; Sachwitz, M.; Schoeniech, B.; Tonisch, F.; Trowitzsch, G.; Vogt, H.; Passaleva, G.; Yeh, S.C.

1993-01-01

A Silicon Microvertex Detector (SMD) has been commissioned for the L3 experiment at the Large Electron-Positron colliding-beam accelerator (LEP) at the European Center for Nuclear Physics, (CERN). The SMD is a 72,672 channel, two layer barrel tracker that is comprised of 96 ac-coupled, double-sided silicon detectors. Details of the design and construction are presented

CERN: A tale of two photons

International Nuclear Information System (INIS)

Anon.

1993-01-01

When precision data from the several million Zs carefully collected over several years by the four big experiments - Aleph, Delphi, L3 and Opal - at CERN's LEP electron-positron collider have otherwise consistently underlined conventional physics, a hint of something unexplained quickly packs the seminar rooms. In 1991, the L3 experiment turned up two examples of Z decays producing a muon pair accompanied by a widely separated pair of high energy photons, with the photon pair in each case taking some 60 GeV of energy (actually 58.8 and 59.0 GeV). Nothing to get excited about at the time, but ongoing data analysis tuned into this channel. This year two more events turned up, one again with a muon pair accompanied by a 60 GeV photon pair, the other with an electron (electron-positron) pair and a 62 GeV photon pair. At first L3 preferred to keep this quiet, and the news was not announced at the major international meeting in Dallas last August. The first public announcement of the four unexplained events (out of a total of 1.6 million Z decays) came in a LEP Experiments Committee session at CERN in October

The Dismantling Project for the Large Electron Positron (LEP) Collider

CERN Document Server

Poole, John

2002-01-01

The LEP accelerator was installed in a circular tunnel 27 km in length with nine access points distributed around the circumference in the countryside and villages which surround CERN's sites. The dismantling project involved the removal in less than 15 months of around 29000 tonnes of equipment from the accelerator itself and a further 10000 tonnes from the four experiments - all of which were located at an average depth of 100 m below ground level. There was no contamination risk in the project and less than 3% of the materials removed were classified as radioactive. However, the materials which were classified as radioactive have to be temporarily stored and they consume considerable resources. The major difficulties for the project were in the establishment of the theoretical radiological zoning, implementation of the traceability systems and making appropriate radiation measurements to confirm the zoning. The absence of detailed guidelines from the French authorities, having no threshold levels for relea...

Civil Engineering Optimisation Tool for the Study of CERN's Future Circular Colliders

OpenAIRE

Cook, Charlie; Goddard, Brennan; Lebrun, Philippe; Osborne, John; Robert, Youri; Sturzaker, C; Sykes, M; Loo, Y; Brasser, J; Trunk, R

2015-01-01

The feasibility of Future Circular Colliders (FCC), possible successors to the Large Hadron Collider (LHC), is currently under investigation at CERN. This paper describes how CERN’s civil engineering team are utilising an interactive tool containing a 3D geological model of the Geneva basin. This tool will be used to investigate the optimal position of the proposed 80km-100km tunnel. The benefits of using digital modelling during the feasibility stage are discussed and some early results of t...

$D^{0}, D^{+}, D_{s}^{+}$, and $\\Lambda_{c}^{+}$ Fragmentation Functions from CERN LEP1

CERN Document Server

Kniehl, Bernd A; Kniehl, Bernd A.; Kramer, Gustav

2005-01-01

We present new sets of nonperturbative fragmentation functions for D^0, D^+, and D_s^+ mesons as well as for Lambda_c^+ baryons, both at leading and next-to-leading order in the MSbar factorization scheme with five massless quark flavors. They are determined by fitting data of e^+e^- annihilation taken by the OPAL Collaboration at CERN LEP1. We take the charm-quark fragmentation function to be of the form proposed by Peterson et al. and thus obtain new values of the epsilon_c parameter, which are specific for our choice of factorization scheme.

Slice of a LEP bending magnet

CERN Multimedia

This is a slice of a LEP dipole bending magnet, made as a concrete and iron sandwich. The bending field needed in LEP is small (about 1000 Gauss), equivalent to two of the magnets people stick on fridge doors. Because it is very difficult to keep a low field steady, a high field was used in iron plates embedded in concrete. A CERN breakthrough in magnet design, LEP dipoles can be tuned easily and are cheaper than conventional magnets.

Environmental monitoring at CERN: present status and future plans for the Large Hadron Collider (LHC)

International Nuclear Information System (INIS)

Hoefert, M.; Stevenson, G.R.; Vojtyla, P.; Wittekind, D.

1998-01-01

The present radiological impact of CERN on the environment is negligible. It is assessed that this will also be the case after the Large Hadron Collider starts operation in 2005. Nevertheless, the environmental monitoring programme at CERN will be further extended, so as to demonstrate that the Organization fully complies with standards and limits for environmental impact of nuclear installations as laid down by authorities in the CERN host countries. (P.A.)

The CERN Antiproton Collider Programme Accelerators and Accumulation Rings

CERN Document Server

Koziol, Heribert

2004-01-01

One of CERN's most daring and successful undertakings was the quest for the intermediate bosons, W and Z. In this paper, we describe the accelerator part of the venture which relied on a number of innovations: an extension of the budding method of stochastic cooling by many orders of magnitude; the construction of the Antiproton Accumulator, depending on several novel accelerator methods and technologies; major modifications to the 26 GeV PS Complex; and the radical conversion of the 300 GeV SPS, which just had started up as an accelerator, to a protonâ€"antiproton collider. The SPS Collider had to master the beamâ€"beam effect far beyond limits reached ever before and had to function in a tight symbiosis with the huge detectors UA1 and UA2.

Inside CERN's Large Hadron Collider from the proton to the Higgs boson

CERN Document Server

AUTHOR|(CDS)2051256

2016-01-01

The book aims to explain the historical development of particle physics, with special emphasis on CERN and collider physics. It describes in detail the LHC accelerator and its detectors, describing the science involved as well as the sociology of big collaborations, culminating with the discovery of the Higgs boson. Readers are led step-by-step to understanding why we do particle physics, as well as the tools and problems involved in the field. It provides an insider's view on the experiments at the Large Hadron Collider.

GPS Precision Timing at CERN

CERN Document Server

Beetham, C G

1999-01-01

For the past decade, the Global Positioning System (GPS) has been used to provide precise time, frequency and position co-ordinates world-wide. Recently, equipment has become available specialising in providing extremely accurate timing information, referenced to Universal Time Co-ordinates (UTC). This feature has been used at CERN to provide time of day information for systems that have been installed in the Proton Synchrotron (PS), Super Proton Synchrotron (SPS) and the Large Electron Positron (LEP) machines. The different systems are described as well as the planned developments, particularly with respect to optical transmission and the Inter-Range Instrumentation Group IRIG-B standard, for future use in the Large Hadron Collider (LHC).

Development and applications of super high energy collider accelerators. Vol. 1

Energy Technology Data Exchange (ETDEWEB)

Abdelaziz, E M [National Center for Nuclear Safety and Radiation Control, Atomic Energy Authority, Cairo, (Egypt)

1996-03-01

This paper presents a review of cyclic accelerators and their energy limitations. A description is given of the phase stability principle and evaluation of the synchrotron, an accelerator without energy limitation. Then the concept of colliding beams emerged to yield doubling of the beam energy as in the Tevatron 2 trillion electron volts (TeV) proton collider at Fermilab, and the large harden collider (LHD) which is now planned as a 14-TeV machine in the 27 Kilometer tunnel of the large electron positron (LEP) collider at CERN. Then presentation is given of the superconducting supercollider (SSC), a giant accelerator complex with energy 40-TeV in a tunnel 87 Kilometers in circumference under the country surrounding Waxahachile in Texas, U.S.A. These superhigh energy accelerators are intended to smash protons against protons at energy sufficient to reveal the nature of matter and to consolidate the prevailing general theory of elementary particles. 12 figs., 1 tab.

Development and applications of super high energy collider accelerators. Vol. 1

International Nuclear Information System (INIS)

Abdelaziz, E.M.

1996-01-01

This paper presents a review of cyclic accelerators and their energy limitations. A description is given of the phase stability principle and evaluation of the synchrotron, an accelerator without energy limitation. Then the concept of colliding beams emerged to yield doubling of the beam energy as in the Tevatron 2 trillion electron volts (TeV) proton collider at Fermilab, and the large harden collider (LHD) which is now planned as a 14-TeV machine in the 27 Kilometer tunnel of the large electron positron (LEP) collider at CERN. Then presentation is given of the superconducting supercollider (SSC), a giant accelerator complex with energy 40-TeV in a tunnel 87 Kilometers in circumference under the country surrounding Waxahachile in Texas, U.S.A. These superhigh energy accelerators are intended to smash protons against protons at energy sufficient to reveal the nature of matter and to consolidate the prevailing general theory of elementary particles. 12 figs., 1 tab

LEP Traceability

CERN Document Server

Billen, R

2000-01-01

After more than ten years of production for high energy physics, CERN's current flagship, LEP, will be closed down definitively October 1st, 2000. Starting immediately, some 30,000 tonnes of LEP materials will be removed from the tunnel to make room for LHC installation. The dismantling project is a major undertaking in terms of resources and constraints, which has to be completed in less than one year. Moreover, since LEP is classified as a nuclear installation in France (as if it was a nuclear power plant), special procedures have to be followed in addition to the normal environmental and safety issues. One major facet of the project is the "traceability" of everything that comes out of the LEP tunnel. This implies that each piece of equipment must be identified and tracked from its origin through any temporary storage to its final destination. Special procedures have to be followed for all materials even if they are not radioactive. As much of the equipment as possible will be recycled or disposed of. This...

For information - Université de Genève : Accelerator Physics Challenges for the Large Hadron Collider at CERN

CERN Multimedia

Université de Genève

2005-01-01

UNIVERSITE DE GENEVE Faculte des sciences Section de physique - Département de physique nucléaire et corspusculaire 24, Quai Ernest-Ansermet - 1211 GENEVE 4 Tél : (022) 379 62 73 Fax: (022) 379 69 92 Mercredi 16 March SEMINAIRE DE PHYSIQUE CORPUSCULAIRE à 17h00 - Auditoire Stückelberg Accelerator Physics Challenges for the Large Hadron Collider at CERN Prof. Olivier Bruning / CERN The Large Hadron Collider project at CERN will bring the energy frontier of high energy particle physics back to Europe and with it push the accelerator technology into uncharted teritory. The talk presents the LHC project in the context of the past CERN accelerator developments and addresses the main challenges in terms of technology and accelerator physics. Information: http://dpnc.unige.ch/seminaire/annonce.html Organizer: A. Cervera Villanueva

Looking For Physics Beyond The Standard Model: Searches For Charged Higgs Bosons At $e^{+}e^{-}$ Colliders

CERN Document Server

Kiiskinen, A P

2004-01-01

This thesis describes direct searches for pair production of charged Higgs bosons performed in the data collected by the DELPHI detector at the LEP collider at CERN. In addition, the possibilities to discover and study heavy charged Higgs bosons at possible future high-energy linear colliders are presented. The existence of charged Higgs bosons is predicted by many extensions of the Standard Model. A possible discovery of these particles would be a solid proof for physics beyond the Standard Model. Discovery of charged Higgs bosons, and measurement of their properties, would also provide useful information about the structure of the more general theory. New analysis methods were developed for the searches performed at LEP. A large, previously unexplored, mass range for cover but no evidence for the existence of the charged Higgs bosons was found. This allowed setting new lower mass limits for the charged Higgs boson within the framework of general two Higgs doublet models. Results have been interpreted and pr...

Inclusive\\pi^{0} production at the CERN p-p collider

CERN Document Server

Banner, M; Bonaudi, Franco; Borer, K; Borghini, M; Chollet, J C; Clark, A G; Conta, C; Darriulat, Pierre; Di Lella, L; Dines-Hansen, J; Dorsaz, P A; Fayard, L; Fraternali, M; Froidevaux, D; Gaillard, J M; Gildemeister, O; Goggi, V G; Grote, H; Hahn, B; Hänni, H; Hansen, J R; Hansen, P; Himel, T; Hungerbühler, V; Jenni, Peter; Kofoed-Hansen, Otto Møgens; Livan, M; Loucatos, Sotirios S; Madsen, B; Mansoulié, B; Mantovani, G C; Mapelli, L; Merkel, B; Møllerud, R; Nilsson, B; Onions, Christopher J; Parrour, G; Pastore, F; Plothow-Besch, H; Repellin, J P; Ringel, J; Rothenberg, A F; Roussarie, A; Sauvage, G; Schacher, J; Siegrist, J L; Stocker, F; Teiger, J; Vercesi, V; Zaccone, Henri; Zeller, W

1982-01-01

Inclusive\\pi^{0} production has been measured at the CERN pp collider, \\sqrt{s}=540 GeV, for 90 degrees production angle and in a range of transverse moment between 1.5 and 4.5 GeV/c. The invariant production cross section is larger than that measured at \\sqrt{s}=53 GeV for p-p collisions. The production of mu mesons and of direct photons is also investigated.

Radiation protection at the LHC, CERN's large hadron collider

International Nuclear Information System (INIS)

Potter, K.M.; Hoefert, M.; Stevenson, G.R.

1996-01-01

After a brief description of the Large Hadron Collider (LHC), which will produce 7 TeV on 7 TeV proton collisions, some of the radiological questions it raises will be discussed. The machine will be built in the 27 km circumference ring-tunnel of an existing collider at CERN. It aims to achieve collision rates of 10 9 per second in two of its high-energy particle detectors. This requires two high-intensity beams of more than 10 14 protons each. Shielding, access control and activation in addition to the high power in the proton-proton collisions must be taken into account. The detectors and local electronics of the particle physics experiments, which will surround these collisions, will have to be radiation resistant. Some of the environmental issues raised by the project will be discussed. (author)

A circular e+e- collider to study H(125) ?

CERN Multimedia

CERN. Geneva

2012-01-01

The strategy for future collider projects will be influenced strongly by the discoveries of the LHC. The discovery by ATLAS and CMS of a 125 GeV/c2 boson naturally focuses attention on concepts for a Higgs factory to study in detail the properties of this remarkable particle. Such a machine should be able to go significantly beyond the capabilities of the LHC and its upgrades for Higgs studies, as well as offering other physics possibilities. Circular electron-positron colliders are among the options that merit further study, for a fully-informed decision to be taken at the appropriate time. Options for CERN include LEP3 – capable of collisions at energies up to ~ 240 GeV, that could be located in the LHC tunnel either after exploitation of the LHC or in parallel – and TLEP – a collider in a larger tunnel in the Geneva area that could reach energies above the top threshold. The physics potential of these circular colliders will be presented and compared to that of other options.

CERN: ALICE in the looking-glass

International Nuclear Information System (INIS)

Anon.

1993-01-01

While proton-proton collisions will provide the main research thrust at CERN's planned LHC high energy collider to be built in the LEP tunnel, its 27-kilometre superconducting magnet ring will also be able to handle all the other high energy beams on the CERN menu, opening up the possibility of both heavy ion and electron-proton collisions to augment the LHC research programme. A major new character in the LHC cast - ALICE (A Large Ion Collider Experiment) - has recently published a letter of intent, announcing its intention to appear on the LHC stage. Three letters of intent for major LHC proton-proton experiments were aired last year (January, page 6), and ALICE, if approved, would cohabit with the final solution for the protonproton sector (see box). Only a single major heavy ion experiment is envisaged. The protonproton detectors have some heavy ion capability, but could only look at some very specific signals. (Detailed plans for LHC's electron proton collision option are on hold, awaiting the initial exploration of this field by the new HERA collider which came into operation last year at the DESY Laboratory in Hamburg.) Describing the ALICE detector and its research aims, spokesman Jurgen Schukraft echoes T.D.Lee's observations on the state of particle physics. It is becoming increasingly clear that resolving some of today's particle puzzles require a deeper understanding of the vacuum

A search for relativistic particles with fractional electric charge at the Cern collider

DEFF Research Database (Denmark)

Banner, M.; Kofoed-Hansen, O.

1983-01-01

A search for relativistic particles with fractional electric charge has been performed at the CERN collider using a telescope of scintillation counters to detect particles with abnormally low ionisation. The thickness of the detector (40 gr cm−2) limits this search to particles without strong...

News from the Library: CERN Library and Collide@CERN present media artist Nataša Teofilović

CERN Multimedia

CERN Library

2012-01-01

The Serbian media artist Nataša Teofilović creates virtual characters which are living art works, often employing animation techniques. She won an honorary mention for her work in the first Prix Ars Electronica Collide@CERN competition for her outstanding digital works which cross the boundaries between virtual and real spaces.  As part of her prize, Arts@CERN offered Nataša the opportunity for a two-day visit to CERN, which is being funded by a Swedish foundation travel grant.   Nataša talks about why and how she creates her digital work and virtual beings, shows examples and reveals insights into the role and status of an artist in her native Serbia. Nataša Teofilović has an PhD and MA in Digital Art (Belgrade University of Arts, Interdisciplinary Studies) and holds a BA in Architecture from Belgrade University of Architecture. She lives in Pančevo, Vojvodina, Serbia. See examples of Nataša’s work here. &quo...

The future e+e- colliders

International Nuclear Information System (INIS)

Voss, G.A.

1990-01-01

At present, the highest energy e + e - colliders are the SLC and LEP. In this paper their future improvement programs for increasing luminosity and/or energy, and the use of longitudinally polarized beams at the interaction point (IP) are discussed. An e + e - collider in the SSC tunnel does not seem to be an attractive option, on both technical and economical grounds, and with LEP, circular colliders have reached the sensible limit of size and cost. Linear colliders which have, in principle, no high energy limit, must overcome a new set of technical problems having to do with beam power limitations, emittance control, superstrong focusing at the IP, strong bunch-bunch interactions at the IP and related backgrounds

LEP Electroweak and QCD Exhibition Lepton-Photon 2001

CERN Multimedia

2001-01-01

The LEP collider an at centre-of-mass energies around the Z mass from 1989 to 1995 (LEP1).F om 1995 to 2000 (LEP2),the energy was gradually increased, crossing the W-pair production threshold in 1996,and eaching 208 GeV in 2000. Each of the four experiments,ALEPH,DELPHI,L3 and OPAL,observed around 4.5 million Z and 12 thousand W-pair events.

The Large Hadron Collider of CERN and the roadmap toward higher performance

CERN Document Server

Rossi, L

2012-01-01

The Large Hadron Collider is exploring the new frontier of particle physics. It is the largest and most ambitious scientific instrument ever built and 100 years after the Rutherford experiment it continues that tradition of “smashing atoms” to unveil the secret of the infinitely small. LHC makes use of all what we learnt in 40 years of hadron colliders, in particular of ISR and Sp-pbarS at CERN and Tevatron at Fermilab, and it is based on Superconductivity, discovered also 100 years ago. Designing, developing the technology, building and finally commissioning the LHC took more than twenty years. While LHC is now successfully running, we are already preparing the future for the next step. First, by increasing of a factor five the LHC luminosity in ten years from now, and then by increasing its energy by a factor two or more, on the horizon of the next twenty years. These LHC upgrades, in luminosity and energy, will be the super-exploitation of the CERN infrastructure and is the best investment that the HEP...

Golden Jubilee Photos: Laying the Ground for the LHC

CERN Multimedia

2004-01-01

In 1997, a prototype of the LHC dipole magnet, with the two beampipes running through the centre. Even before digging the LEP tunnel, in the early eighties CERN scientists began laying the plans for the second-generation collider to go in the tunnel. From the beginning, physicists had their eyes fixed on certain goals such as finding the Higgs boson and signs of supersymmetric particles. To reach the desired energies within the LEP tunnel, instead of LEP's electrons and positrons, the next collider would need to use more massive particles that radiate away less energy as they travel around the circular tunnel. Also, since the United States was planning the Superconducting Super Collider (SSC) with a circumference even larger than LEP's, CERN scientists conceived of their next collider as a "high-luminosity" machine that would excel at producing a high number of collisions. But since making a strong antiproton beam is laborious, this collider would have to smash together two proton beams. Thus the LHC project ...

Inside the LEP control room at start-up

CERN Multimedia

1989-01-01

Physicists grouped around a screen in the LEP control room at the strat-up of LEP on 14 July 1989. The emotion of the moment is clear. Carlo Rubbia, Director-General of CERN at the time, is in the centre and on his left, Herwig Schopper, former Director-General of the Organization.

CERN celebrating the Lowering of the final detector element for large Hadron Collider

CERN Multimedia

2008-01-01

In the early hours of the morning the final element of the Compact Muon Solenoid (CMS) detector began the descent into its underground experimental cavern in preparation for the start-up of CERNs Large Hadron Collider (LHC) this summer. This is a pivotal moment for the CMS collaboration.

The fastbus trigger modules for the SAT detector in the DELPHI experiment at LEP, CERN

International Nuclear Information System (INIS)

Alvsvaag, S.J.

1992-09-01

This thesis describes the functionality and performance of the fastbus trigger modules for the Small Angle Tagger (SAT) detector in the DELPHI experiment at the LEP machine at CERN. The main purpose of the modules is to provide a Bhabha trigger for the SAT calorimeter used for luminosity measurements. The author has bee responsible for the design, production, testing and installation of the trigger modules. All the test programs necessary to confirm that the modules function according to the specifications are included in this work. Is does not, however, aim to make detailed technical descriptions of the modules. 44 refs., 39 figs., 18 tabs

CERN Library | Pauline Gagnon presents the book "Who cares about particle physics? : making sense of the Higgs boson, the Large Hadron Collider and CERN" | 15 September

CERN Multimedia

CERN Library

2016-01-01

"Who cares about particle physics? : making sense of the Higgs boson, the Large Hadron Collider and CERN ", by Pauline Gagnon. Thursday 15 September 2016, 16:00 - 17:30 in the CERN Library (Bldg 52 1-052) *Coffee will be served at 15:30* CERN, the European Laboratory for particle physics, regularly makes the news. What kind of research happens at this international laboratory and how does it impact people's daily lives? Why is the discovery of the Higgs boson so important? Particle physics describes all matter found on Earth, in stars and all galaxies but it also tries to go beyond what is known to describe dark matter, a form of matter five times more prevalent than the known, regular matter. How do we know this mysterious dark matter exists and is there a chance it will be discovered soon? About sixty countries contributed to the construction of the gigantic Large Hadron Collider (LHC) at CERN and its immense detectors. Dive in to discover how international teams of researchers...

Design optimization of 600 A-13 kA current leads for the Large Hadron Collider project at CERN

CERN Document Server

Spiller, D M; Al-Mosawl, M K; Friend, C M; Thacker, P; Ballarino, A

2001-01-01

The requirements of the Large Hadron Collider project at CERN for high-temperature superconducting (HTS) current leads have been widely publicized. CERN require hybrid current leads of resistive and HTS materials with current ratings of 600 A, 6 kA and 13 kA. BICC General Superconductors, in collaboration with the University of Southampton, have developed and manufactured prototype current leads for the Large Hadron Collider project. The resistive section consists of a phosphorus de-oxidized copper conductor and heat exchanger and the HTS section is constructed from BICC General's (Pb, Bi)2223 tapes with a reduced thermal conductivity Ag alloy sheath. We present the results of the materials optimization studies for the resistive and the HTS sections. Some results of the acceptance tests at CERN are discussed. (9 refs).

Monitoring the waste water of LEP

CERN Document Server

Rühl, I

1999-01-01

Along the LEP sites CERN is discharging water of differing quality and varying amounts into the local rivers. This wastewater is not only process water from different cooling circuits but also water that infiltrates into the LEP tunnel. The quality of the discharged wastewater has to conform to the local environmental legislation of our Host States and therefore has to be monitored constantly. The most difficult aspect regarding the wastewater concerns LEP Point 8 owing to an infiltration of crude oil (petroleum), which is naturally contained in the soil along octant 7-8 of the LEP tunnel. This paper will give a short summary of the modifications made to the oil/water separation unit at LEP Point 8. The aim was to obtain a satisfactory oil/water separation and to install a monitoring system for a permanent measurement of the amount of hydrocarbons in the wastewater.

LEP Dismantling: Wagons Roll!

CERN Multimedia

2001-01-01

The first trucks transporting material from LEP and its four experiments left CERN on 31 January. Since the LEP dismantling operation began, the material had been waiting to be removed from the sites of the four experiments and the special transit area on the Prévessin site. On the evening of 30 January, the French customs authorities gave the green light for the transport operation to begin. So first thing the next day, the two companies in charge of recycling the material, Jaeger & Bosshard (Switzerland) and Excoffier (France), set to work. Only 1500 truckloads to go before everything has been removed!

LEP results

International Nuclear Information System (INIS)

Thresher, J.J.

1990-01-01

The first period of LEP operation ended on 22nd December 1989, rather less than two weeks before the start of this Conference. It brought to a close a most exciting time at CERN, starting in July 1989, when those involved in commissioning LEP attempted for the first time to start up the complete machine and then to give the experiments their first taste of what LEP had in store for them. By July almost all sections of LEP had been individually checked out. In particular, the entire injection chain had been tested with positrons a year earlier when a very successful injection test into the first completed LEP octant was carried out. Also by July the LEP detectors had been installed and were ready to take data with at least the most important sub-detector systems able to operate. By way of introduction a brief history of these first months of LEP operation is given in this paper. The first steps in bringing LEP into operation started on 14th July 1989 when positrons were injected into the ring for the first time. After only 55 minutes of magnet adjustments they had completed a full turn at the injection energy of 20 GeV. Further commissioning with positrons at this energy then followed to establish a stable circulating beam and then on 25th July the first electrons were successfully injected into LEP. By 31st July, after much work on beam accumulation had been done, a current of some 250 μA of positrons, i.e. about 60 μA in each of the four bunches was reached at 20 GeV and four days later on 4th August positrons were successfully ramped up to 47.5 GeV. Finally, at 23.15 on 13th August positrons were successfully ramped up to 47.5 GeV. Finally, at 23.15 on 13th August, just less than one month after the start of LEP commissioning, electrons and positrons were brought into collision at an energy of 45.5 GeV per beam

Search for γ-Z-Z' electroweak interference at e+e- collider LEP2

International Nuclear Information System (INIS)

Pankov, A.A.

2000-01-01

Indirect effects of Z' bosons at the e + e - collider LEP2 in e + e - → μ + μ - through the new integrated observables σ ± were studied. It is shown that these observables provide more definite information on Z' effects with respect to canonical observables, σ μμ and A FB . It is found that the deviations Δσ ± induced by Z' bosons have the specific energy dependence mostly defined by the Standard Model parameters. It allows to provide the unambiguous model-independent predictions for the deviations. In particular, there were found two energies, √s + ≅ 78 GeV and √s - = 113 GeV, where σ + and σ - vanish both in the Standard Model and in case of Z'. These energies are quite convenient to search for phenomenological consequences of alternative new physics sources beyond the Z' [ru

People and things. CERN Courier, Sep-Oct 1990, v. 30(7)

Energy Technology Data Exchange (ETDEWEB)

Anon.

1990-09-15

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events: ; At the June meeting of CERN Council, Director General Carlo Rubbia outlined the plan for the LHC proton collider in the LEP tunnel as CERN's major project for the coming decade. ; After initial trials of injection and storage of oxygen ions last year, CERN's LEAR low energy 'antiproton' ring has electron-cooled oxygen ions, achieving momentum 'spreads' down to 4 x 10{sup -4} , and stacked up to 13.8 x 10{sup 9} charges at 11.4 MeV per nucleon, with subsequent acceleration taking the ions to 408 Me V per nucleon before extraction for experiments. ; Under the North Holland Physics Publishing imprint, the History of CERN, Volume 1, became available in 1987. ; The Atlanta Conference on the SSC will be held on the 13-15 November and will focus on industrial and scientific opportunities, covering the status of the project, industry, university and laboratory participation, the development efforts now underway for major detectors and progress toward defining the initial research programme.

People and things. CERN Courier, Sep-Oct 1990, v. 30(7)

International Nuclear Information System (INIS)

Anon.

1990-01-01

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events: ; At the June meeting of CERN Council, Director General Carlo Rubbia outlined the plan for the LHC proton collider in the LEP tunnel as CERN's major project for the coming decade. ; After initial trials of injection and storage of oxygen ions last year, CERN's LEAR low energy 'antiproton' ring has electron-cooled oxygen ions, achieving momentum 'spreads' down to 4 x 10 -4 , and stacked up to 13.8 x 10 9 charges at 11.4 MeV per nucleon, with subsequent acceleration taking the ions to 408 Me V per nucleon before extraction for experiments. ; Under the North Holland Physics Publishing imprint, the History of CERN, Volume 1, became available in 1987. ; The Atlanta Conference on the SSC will be held on the 13-15 November and will focus on industrial and scientific opportunities, covering the status of the project, industry, university and laboratory participation, the development efforts now underway for major detectors and progress toward defining the initial research programme

ALEPH model

CERN Multimedia

1989-01-01

A wooden model of the ALEPH experiment and its cavern. ALEPH was one of 4 experiments at CERN's 27km Large Electron Positron collider (LEP) that ran from 1989 to 2000. During 11 years of research, LEP's experiments provided a detailed study of the electroweak interaction. Measurements performed at LEP also proved that there are three – and only three – generations of particles of matter. LEP was closed down on 2 November 2000 to make way for the construction of the Large Hadron Collider in the same tunnel. The cavern and detector are in separate locations - the cavern is stored at CERN and the detector is temporarily on display in Glasgow physics department. Both are available for loan.

Taking Energy to the Physics Classroom from the Large Hadron Collider at CERN

Science.gov (United States)

Cid, Xabier; Cid, Ramon

2009-01-01

In 2008, the greatest experiment in history began. When in full operation, the Large Hadron Collider (LHC) at CERN will generate the greatest amount of information that has ever been produced in an experiment before. It will also reveal some of the most fundamental secrets of nature. Despite the enormous amount of information available on this…

Missing energy at LEP2: W boson and new physics; Energie manquante a LEP2: boson W et physique nouvelle

Energy Technology Data Exchange (ETDEWEB)

Zerwas, Dirk [Lab. de l`Accelerateur Lineaire, Paris-11 Univ., 91 - Orsay (France)

1998-04-01

In 1995 LEP, CERN`s large e{sup +}e{sup -} collider, increased its center-of-mass energy beyond the Z boson resonance up to 184 GeV in 19997. The data recorded by the ALEPH detector allow to study the parameters of the standard model and to search for new particles. The mass of the W boson can be determined at LEP via the measurement of the cross section of W pairs at the production threshold. Two selections for the final states l{nu}l{nu} and {tau}{nu}qq-bar are developed. In combination with the other decay channels, the mass of the W boson and its branching ratios are measured. The reaction e{sup +}e{sup -} {yields} We{nu} gives access to the coupling {gamma}WW. The cross section of this process is measured and limits on the anomalous couplings ({lambda}{sub {gamma}},{kappa}{sub {gamma}}) are determined. The non-minimal standard model with an extra scalar doublet predicts the existence of charged Higgs bosons. A selection of the final state {tau}{nu}qq`-bar is developed. In absence of a signal, limits on the mass of the charged Higgs bosons are determined. In a supersymmetric theory each boson is associated to a fermion and vice versa. A search for sleptons, the supersymmetric partners of the leptons, is performed. The result is interpreted in the framework of the minimal supersymmetric extension of the standard model (MSSM). Moreover, in the MSSM a practically invisible W decay is possible. This decay can be detected if the second W decays to standard model particles. A limit on the invisible branching ratio of the W boson is deduced. (author) 116 refs., 73 figs., 12 tabs.

Collider workshop

International Nuclear Information System (INIS)

Anon.

1982-01-01

The promise of initial results after the start of operations at CERN's SPS proton-antiproton collider and the prospects for high energy hadron collisions at Fermilab (Tevatron) and Brookhaven (ISABELLE) provided a timely impetus for the recent Topical Workshop on Forward Collider Physics', held at Madison, Wisconsin, from 10-12 December. It became the second such workshop to be held, the first having been in 1979 at the College de France, Paris. The 100 or so participants had the chance to hear preliminary results from the UA1, UA4 and UA5 experiments at the CERN SPS collider, together with other new data, including that from proton-antiproton runs at the CERN Intersecting Storage Rings

LEP takes to the hills

International Nuclear Information System (INIS)

Anon.

1981-01-01

From 1-7 June the focal point of thinking about the European project for a very high energy electron-positron machine, LEP, moved up into the Swiss mountains. The European Committee for Future Accelerators, ECFA, organized a 'General Meeting on LEP' at the alpine resort of Villars. This was in the long tradition of ECFA meetings which try to ensure a broad consultation of the European High Energy Physics community before major decisions on CERN projects are taken. Over 400 physicists gathered at the Palace Hotel where they were very agreeably immersed in the happy Club Mediterranee ambience. The Conference was successful beyond expectation and left the feeling that the contacts and discussions had moved LEP significantly further towards its goals. Above all it demonstrated again the keenness of the community to become involved in the experimental programme of LEP and the great belief in the scientific promise of the machine

Lep vertical tunnel movements - lessons for future colliders

Energy Technology Data Exchange (ETDEWEB)

Pitthan, R [CERN-Conseil Europeen pour la recherche nucleaire, Clic-Study Group and the Survey Group, Geneve (Switzerland)

1999-07-01

The data from 10 years of vertical surveys verify for all of LEP the previous observation, localized to region P1, that LEP floor movements are predominantly deterministic. This rules out the ATL model as being correct for this tunnel. If generalized, for yearly movements a random ATL model underestimates the possible maximum long-term motions. In contrast, extrapolation of the LEP vertical data to the short-term (hours and days) time-scale shows that the random approach predicts larger short-term movements than the deterministic model. This means that simulations using the ATL hypothesis are overtly pessimistic with regard to the frequency of operational realignments required. Depending on the constants chosen in the models these differences can be large, of the order of a magnitude and more. This paper deals solely with the directly measured months-to-years tunnel motions in rock, and the extrapolation of such ground motions to hourly or daily time-spans It does not, address the important question of the contribution of hourly-scale movements of the accelerator components, which could have a random part, to the combined motion. Nor does it address the question of movements of accelerator tunnels like HERA or TRISTAN which are built in water and debris, and not in solid rock. (author)

Lep vertical tunnel movements - lessons for future colliders

International Nuclear Information System (INIS)

Pitthan, R.

1999-01-01

The data from 10 years of vertical surveys verify for all of LEP the previous observation, localized to region P1, that LEP floor movements are predominantly deterministic. This rules out the ATL model as being correct for this tunnel. If generalized, for yearly movements a random ATL model underestimates the possible maximum long-term motions. In contrast, extrapolation of the LEP vertical data to the short-term (hours and days) time-scale shows that the random approach predicts larger short-term movements than the deterministic model. This means that simulations using the ATL hypothesis are overtly pessimistic with regard to the frequency of operational realignments required. Depending on the constants chosen in the models these differences can be large, of the order of a magnitude and more. This paper deals solely with the directly measured months-to-years tunnel motions in rock, and the extrapolation of such ground motions to hourly or daily time-spans It does not, address the important question of the contribution of hourly-scale movements of the accelerator components, which could have a random part, to the combined motion. Nor does it address the question of movements of accelerator tunnels like HERA or TRISTAN which are built in water and debris, and not in solid rock. (author)

University of Tennessee deploys force10 C-series to analyze data from CERN's Large Hadron Collider

CERN Multimedia

2007-01-01

"Force20 networks, the pioneer in building and securing reliable networks, today announced that the University of Tennessee physics department has deployed the C300 resilient switch to analyze data form CERN's Large Hadron Collider." (1 page)

Assessing Risk in Costing High-energy Accelerators: from Existing Projects to the Future Linear Collider

CERN Document Server

Lebrun, Philippe

2010-01-01

High-energy accelerators are large projects funded by public money, developed over the years and constructed via major industrial contracts both in advanced technology and in more conventional domains such as civil engineering and infrastructure, for which they often constitute one-of markets. Assessing their cost, as well as the risk and uncertainty associated with this assessment is therefore an essential part of project preparation and a justified requirement by the funding agencies. Stemming from the experience with large circular colliders at CERN, LEP and LHC, as well as with the Main Injector, the Tevatron Collider Experiments and Accelerator Upgrades, and the NOvA Experiment at Fermilab, we discuss sources of cost variance and derive cost risk assessment methods applicable to the future linear collider, through its two technical approaches for ILC and CLIC. We also address disparities in cost risk assessment imposed by regional differences in regulations, procedures and practices.

High energy accelerator and colliding beam user group. Progress report, March 1, 1983-February 29, 1984

International Nuclear Information System (INIS)

1983-01-01

Topics covered in this research summary include: status of the OPAL collaboration at LEP, CERN; two-photon physics at PLUTO; search for new particles at JADE; neutrinoless double beta decay at DESY; Fermilab jet experiment; neutrino deuterium experiment in the 15 foot bubble chamber at Fermilab; deep inelastic muon experiment at Fermilab; new experiments at the proton-antiproton collider; neutrino-electron scattering at Los Alamos; parity violation in proton-proton scattering; an upgrade of laboratory and computer facilities; and a study of bismuth germanate as a durable scintillation crystal

Report of the Working Group on High Luminosities at LEP

International Nuclear Information System (INIS)

Blucher, E.; Jowett, J.; Merritt, F.; Mikenberg, G.; Panman, J.; Renard, F.M.; Treille, D.

1991-01-01

The availability of an order-of-magnitude increase in the luminosity of LEP (CERN's Large Electron-Positron Collider) can dramatically increase its physics output. With the help of a pretzel scheme, it should be possible to increase the peak luminosity beyond 10 32 cm -2 s -1 at the Z energy and to significantly increase the luminosity around the W-pari threshold. This report spells out the physics possibilities opened up by the availability of several 10 7 Z events. The three domains of physics that benefit mostly from this abundance are very accurate measurements of Standard Model parameters, rare decays of the Z, and the physics of fermion-antifermion states such as B physics. The possibilities and implications for the machine and the experiments are presented. The physics possibilities are explored and compared with those at other accelerators. (orig.)

Status of CERN linear collider studies

International Nuclear Information System (INIS)

Guignard, G.

1991-01-01

A description is given of the topics which have been the subject of studies and developments, and the status of the work on a CERN linear collider (CLIC) is summarized. Progress was made on the test facility, for investigating the critical question of generating the short and intense bunches required for the driving beam. In the drive linac, the wake fields associated with the transfer structure and the consequent stability issue are severe. Therefore, studies and calculations are carried on overmoded pipes, cylindrical with either symmetrical corrugations or combs asymmetrically placed on one side. In the main linac, the question was addressed of minimizing the energy spread by shifting the phase of the accelerating voltage, leading to requirements conflicting with those for beam stability. A prototype of high-gradient accelerating cells has been built and measured. In parallel with the design studies of the final focus system, a model of a small-aperture, high-gradient quadrupole, that could be part of the scheme, has been realized and measured

TLEP design study forges ahead

CERN Multimedia

Alain Blondel & Mike Koratzinos

2013-01-01

As the Future Circular Collider (FCC) study is launched, one of its component parts, TLEP, enjoys a successful workshop at CERN. The FCC study looks at all options for a future circular collider with the emphasis on a hadron machine with TLEP as a possible intermediate step.   The poster of the sixth TLEP workshop that took place at CERN. Japanese artist Kazuya Akimoto kindly agreed to the use of one of his works as the basis for the poster’s backdrop. October 16 to 18 saw a three-day workshop on TLEP, the sixth in the series. The workshop took place at CERN and was well attended, informative and stimulating. To name just one of the influential people present, Herwig Schopper, ex-Director General of CERN and instrumental in the approval, construction and success of LEP, was among the participants. But what exactly is TLEP? The name was, somehow serendipitously, coined from future lepton collider option studies and stands for triple-LEP, a machine three times the size of LEP. But th...

Minimum Bias Measurements with the ATLAS Detector at the CERN Large Hadron Collider

CERN Document Server

Leyton, M

2009-01-01

The Large Hadron Collider (LHC) at CERN will collide bunches of protons (p) at a center-of-mass energy of sqrt(s) = 14 TeV and a rate of 40 MHz. The unprecedented collision energy and interaction rate at the LHC will allow us to explore the TeV mass scale and take a major step forward in our understanding of the fundamental nature of matter. The initial physics run of the LHC is expected to start in November 2009 and continue until the end of 2010, with collisions at sqrt(s) = 900 GeV, 7 TeV and 10 TeV. ATLAS (A Toroidal LHC ApparatuS) is a 4pi general-purpose detector designed for studying LHC collisions at the particle level. The design and layout of ATLAS are intended to cover the wide spectrum of physics signatures that are possible at the TeV mass scale. Construction and installation of the ATLAS detector at CERN are now complete. This dissertation focuses on measuring the properties of inelastic pp interactions at the LHC with the ATLAS detector. A method for measuring the central pseudorapidity den...

Protection of the CERN Large Hadron Collider

Science.gov (United States)

Schmidt, R.; Assmann, R.; Carlier, E.; Dehning, B.; Denz, R.; Goddard, B.; Holzer, E. B.; Kain, V.; Puccio, B.; Todd, B.; Uythoven, J.; Wenninger, J.; Zerlauth, M.

2006-11-01

The Large Hadron Collider (LHC) at CERN will collide two counter-rotating proton beams, each with an energy of 7 TeV. The energy stored in the superconducting magnet system will exceed 10 GJ, and each beam has a stored energy of 362 MJ which could cause major damage to accelerator equipment in the case of uncontrolled beam loss. Safe operation of the LHC will therefore rely on a complex system for equipment protection. The systems for protection of the superconducting magnets in case of quench must be fully operational before powering the magnets. For safe injection of the 450 GeV beam into the LHC, beam absorbers must be in their correct positions and specific procedures must be applied. Requirements for safe operation throughout the cycle necessitate early detection of failures within the equipment, and active monitoring of the beam with fast and reliable beam instrumentation, mainly beam loss monitors (BLM). When operating with circulating beams, the time constant for beam loss after a failure extends from apms to a few minutes—failures must be detected sufficiently early and transmitted to the beam interlock system that triggers a beam dump. It is essential that the beams are properly extracted on to the dump blocks at the end of a fill and in case of emergency, since the beam dump blocks are the only elements of the LHC that can withstand the impact of the full beam.

LEP a new instrument for high-energy physics

CERN Document Server

Udo, Fred

1981-01-01

Describes the LEP project of CERN. LEP (large electron/positron storage ring) is to be used to investigate electron/positron collisions at 44 to 260 GeV. The circumference of the ring will be 30.6 km. The theory is outlined. Two circular systems of beam bundles (electrons and positrons) move in opposite directions and are accelerated and focused (to 0.4 mm diameter) until collisions take place. (11 refs).

From the LHC to future colliders. CERN Theory Institute summary report

International Nuclear Information System (INIS)

Roeck, A. de; Ellis, J.; Wells, J.; Gripaios, B.; Dittmar, M.; Grojean, C.; Heinemeyer, S.; Jakobs, K.; Schumacher, M.; Duehrssen, M.; Weiglein, G.; Moortgat-Pick, G.; Morton-Thurtle, V.; Rolbiecki, K.; Smillie, J.; Tattersall, J.; Azuelos, G.; Dawson, S.; Assamagan, K.; Gopalakrishna, S.; Han, T.; Hewett, J.; Rizzo, T.; Lancaster, M.; Ozcan, E.; Mariotti, C.; Moortgat, F.; Polesello, G.; Riemann, S.; Bechtle, P.; Carena, M.; Juste, A.; Chachamis, G.; Chen, K.F.; Hou, W.S.; Curtis, S. de; Desch, K.; Wienemann, P.; Dreiner, H.; Foster, B.; Frandsen, M.T.; Giammanco, A.; Godbole, R.; Govoni, P.; Gunion, J.; Hollik, W.; Isidori, G.; Kalinowski, J.; Krawczyk, M.; Korytov, A.; Kou, E.; Kraml, S.; Martin, A.; Milstead, D.; Moenig, K.; Mele, B.; Pieri, M.; Plehn, T.; Reina, L.; Richter-Was, E.; Sannino, F.; Schram, M.; Sultansoy, S.; Uwer, P.; Webber, B.

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 -1 of integrated luminosity, of the proposed sLHC luminosity upgrade, of the ILC, of CLIC, of the LHeC and of a muon collider. The four Working Groups considered possible scenarios for the first 10 fb -1 of data at the LHC in which (i) a state with properties that are compatible with a Higgs boson is discovered, (ii) no such state is discovered either because the Higgs properties are such that it is difficult to detect or because no Higgs boson exists, (iii) a missing-energy signal beyond the Standard Model is discovered as in some supersymmetric models, and (iv) some other exotic signature of new physics is discovered. In the contexts of these scenarios, the Working Groups reviewed the capabilities of the future colliders to study in more detail whatever new physics may be discovered by the LHC. Their reports provide the particle physics community with some tools for reviewing the scientific priorities for future colliders after the LHC produces its first harvest of new physics from multi-TeV collisions. (orig.)

L3 experiment dismantling at LEP

CERN Multimedia

Laurent Guiraud

2001-01-01

The last muon chamber is removed from the L3 experiment at the LEP collider, which was in operation from 1989 to 2000. The large red magnet yoke will be reused by the ALICE experiment when the LHC is constructed.

LEP asymmetries and fits of the standard model

International Nuclear Information System (INIS)

Pietrzyk, B.

1994-01-01

The lepton and quark asymmetries measured at LEP are presented. The results of the Standard Model fits to the electroweak data presented at this conference are given. The top mass obtained from the fit to the LEP data is 172 -14-20 +13+18 GeV; it is 177 -11-19 +11+18 when also the collider, ν and A LR data are included. (author). 10 refs., 3 figs., 2 tabs

A search for scalar leptoquarks at the CERN anti pp collider

International Nuclear Information System (INIS)

Alitti, J.; Ambrosini, G.; Ansari, R.; Autiero, D.; Bareyre, P.; Bertram, I.A.; Blaylock, G.; Bonamy, P.; Borer, K.; Bourliaud, M.; Buskulic, D.; Carboni, G.; Cavalli, D.; Cavasinni, V.; Cenci, P.; Chollet, J.C.; Conta, C.; Costa, G.; Costantini, F.; Cozzi, L.; Cravero, A.; Curatolo, M.; Dell'Acqua, A.; DelPrete, T.; DeWolf, R.S.; DiLella, L.; Ducros, Y.; Egan, G.F.; Einsweiler, K.F.; Esposito, B.; Fayard, L.; Federspiel, A.; Ferrari, R.; Fraternali, M.; Froidevaux, D.; Fumagalli, G.; Gaillard, J.M.; Gianotti, F.; Gildemeister, O.; Goessling, C.; Goggi, V.G.; Gruenendahl, S.; Hara, K.; Hellman, S.; Hrivnac, J.; Hufnagel, H.; Hugentobler, E.; Hultqvist, K.; Iacopini, E.; Incandela, J.; Jakobs, K.; Jenni, P.; Kluge, E.E.; Kurz, N.; Lami, S.; Lariccia, P.; Lefebvre, M.; Linssen, L.; Livan, M.; Lubrano, P.; Magneville, C.; Mandelli, L.; Mapelli, L.; Mazzanti, M.; Meier, K.; Merkel, B.; Meyer, J.P.; Moniez, M.; Moning, R.; Morganti, M.; Mueller, L.; Munday, D.J.; Nessi, M.; Nessi-Tedaldi, F.; Onions, C.; Pal, T.; Parker, M.A.; Parrour, G.; Pastore, F.; Pennacchio, E.; Pentney, J.M.; Pepe, M.; Perini, L.; Petridou, C.; Petroff, P.; Plothow-Besch, H.; Polesello, G.; Poppleton, A.; Pretzl, K.; Primavera, M.; Punturo, M.; Repellin, J.P.; Rimoldi, A.; Sacchi, M.; Scampoli, P.; Schacher, J.; Schmidt, B.; Simak, V.; Singh, S.L.; Sondermann, V.; Spiwoks, R.; Stapnes, S.; Talamonti, C.; Tondini, F.; Tovey, S.N.; Tsesmelis, E.; Unal, G.; Valdata-Nappi, M.; Vercesi, V.; Weidberg, A.R.; Wells, P.S.; White, T.O.; Wood, D.R.; Wotton, S.A.; Zaccone, H.; Zylberstejn, A.

1992-01-01

A search has been made for scalar leptoquark pair production with the upgraded UA2 detector at the CERN anti pp Collider at √s=630 GeV, investigating decays of the leptoquark into a quark and either an electron or an electron neutrino. From an event sample corresponding to an integrated luminosity of 13 pb -1 a lower limit has been determined for the mass of first generation leptoquarks, yielding 67 GeV (95% CL) for a scalar leptoquark decaying with a 50% branching ratio into a quark and an electron. (orig.)

OPAL

International Nuclear Information System (INIS)

Miller, David

1991-01-01

The kernel of the OPAL (Omni Purpose Apparatus for LEP) collaboration at CERN's LEP electron-positron collider came from the JADE (JApan, Deutschland, England) experiment at the lower energy PETRA electron positron collider at DESY, Hamburg. The name of a semi-precious stone is a reminder of the JADE tradition, while the spelled-out version conveys versatility

OPAL

Energy Technology Data Exchange (ETDEWEB)

Miller, David

1991-06-15

The kernel of the OPAL (Omni Purpose Apparatus for LEP) collaboration at CERN's LEP electron-positron collider came from the JADE (JApan, Deutschland, England) experiment at the lower energy PETRA electron positron collider at DESY, Hamburg. The name of a semi-precious stone is a reminder of the JADE tradition, while the spelled-out version conveys versatility.

Perspectives on large Linear Colliders

International Nuclear Information System (INIS)

Richter, B.

1987-01-01

The accelerator community now generally agrees that the Linear Collider is the most cost-effective technology for reaching much higher energies in the center-of-mass than can be attained in the largest of the e + e - storage rings, LEP. Indeed, even as the first linear collider, the SLC at SLAC, is getting ready to begin operations groups, at SLAC, Novosibirsk, CERN and KEK are doing R and D and conceptual design studies on a next generation machine in the 1 TeV energy region. In this perspectives talk I do not want to restrict my comments to any particular design, and so I will talk about a high-energy machine as the NLC, which is shorthand for the Next Linear Collider, and taken to mean a machine with a center-of-mass energy someplace in the 0.5 to 2 TeV energy range with sufficient luminosity to carry out a meaningful experimental program. I want to discuss three main items with you. The first is the interrelation of energy and luminosity requirements. These two items impose severe constraints on the accelerator builder. Next, I will give an introduction to linear collider design, concentrating on what goes on at the collision point, for still another constraint comes here from the beam-beam interaction which further restricts the choices available to the accelerator builder.Then, I want to give my impressions of the state of the technology available for building these kinds of machines within the next decade

Inter-string Bose-Einstein correlations in hadronic Z decays using the L3 detector at LEP

CERN Document Server

Wang, Qin

2008-01-01

Bose-Einstein Correlations (BEC) of identical bosons can be used for the femtoscopy of the pro- duction properties of bosons in high energy particle collisions. This quantum mechanical BEC effect is a direct consequence of the symmetrization of the wave function of a boson system and is frequently used on photons in Astophysics to measure the angular size and other properties of distant stars. In particle collisions, the effect can be observed experimentally as an enhancement of the production of identical bosons with small four-momentum difference Q relative to a production that would occur in a world without Bose-Einstein statistics. In this thesis, BEC are studied between identical pions produced in electron-positron collisions at a center-of-mass energy of 91 GeV in the LEP e+ e− Collider of CERN, near Geneva. The final-state particles of these collisions are detected in the detector of the L3 experiment, which is positioned at one of the four intersections of LEP. According to the present picture of bo...

Energy Extraction in the CERN Large Hadron Collider a Project Overview

CERN Document Server

Dahlerup-Petersen, K; Kazmine, B; Medvedko, A S; Sytchev, V V; Vasilev, L B

2001-01-01

In case of a resistive transition (quench), fast and reliable extraction of the magnetic energy, stored in the superconducting coils of the electromagnets of a particle collider, represents an important part of its magnet protection system. In general, the quench detectors, the quench heaters and the cold by-pass diodes across each magnet, together with the energy extraction facilities provide the required protection of the quenching superconductors against damage due to local energy dissipation. In CERN's LHC machine the energy stored in each of its eight superconducting dipole chains exceeds 1300 MJ. Following an opening of the extraction switches this energy will be absorbed in large extraction resistors located in the underground collider tunnel or adjacent galleries, during the exponential current decay. Also the sixteen, 13 kA quadrupole chains (QF, QD) and more than one hundred and fifty, 600 A circuits of the corrector magnets will be equipped with extraction systems. The extraction switch-gear is bas...

Design and Installation Challenges of the Neutral Beam Absorbers for the Large Hadron Collider at CERN

OpenAIRE

Fernández Vélez, Óscar

2005-01-01

El CERN (Consejo Europeo de Investigación Nuclear) está construyendo su nuevo acelerador de partículas en la frontera franco-suiza. Actualmente en la fase de instalación, El Large Hadron Collider (LHC), con 26,7 kilómetros de longitud a 100 metros bajo tierra, será el mayor y más potente acelerador de partículas jamás construido. A su llegada al CERN, cada uno de casi 2000 imanes superconductores que formarán parte del acelerador debe ser verificado, ensamblado y transportado hasta ...

Particle physics and the LEP project

International Nuclear Information System (INIS)

Roussarie, A.

1985-01-01

A very didactic chronological account of the last 20 years of elementary particle physics is presented. After some recall on matter constituents and interactions between these constituents, some details are given on researches which will be made in LEP, the e + -e - collider [fr

Prompt D*+ production in proton-proton and lead-lead collisions, measured with the ALICE experiment at the CERN Large Hadron Collider

NARCIS (Netherlands)

de Rooij, R. S.

2013-01-01

In this thesis the results are presented of the first measurements of the D*+ meson nuclear modification factor RAA in heavy ion collisions at the Large Hadron Collider (LHC) using the ALICE (A Large Ion Collider Experiment) detector at CERN. These open charmed mesons are a useful tool to

Feasibility study for a B-meson factory in the CERN ISR tunnel

International Nuclear Information System (INIS)

Nakada, T.

1990-01-01

A feasibility study has been made for a B-meson factory, using the ISR tunnel and the LEP injector at CERN. An electron-positron collider operated with asymmetric beam energies of 8 and 3.5 GeV at a luminosity of 10 34 cm -2 s -1 will permit decisive answers on the question of CP violation within the framework of the Standard Model. This report outlines the physics motivation and detector requirements and gives a description of the machine design. It is proposed that the design goal is reached in two stages, with a collider with two rings of equal size. In the first stage a luminosity of 10 33 cm -2 s -1 may be achieved, allowing a rich programme of charm, beauty and τ-lepton physics. A further tenfold increase of the luminosity would require additional R and D on various machine aspects. (orig.)

Detectors for Linear Colliders: Physics Requirements and Experimental Conditions (1/4)

CERN Multimedia

CERN. Geneva

2010-01-01

How is the anticipated physics program of a future e+e- collider shaping the R&D for new detectors in collider particle physics ? This presentation will review the main physics requirements and experimental conditions comparing to LHC and LEP. In particular, I shall discuss how e+e- experimentation is expected to change moving from LEP-2 up to multi-TeV energies.

The history of the LEP proposal

International Nuclear Information System (INIS)

Stafford, G.H.

1979-01-01

Following recommendations by ECFA, the European Committee for Future Accelerators, that the next major European high energy facility should be a large electron positron collider, about 400 physicists and engineers from the 12 CERN member nations have been contributing to preparatory work as members of working groups. In particular, design and feasibility studies have been issued for (a) a 100 GeV per beam collider with a 51.5 km circumference, (b) a 70 GeV per beam collider with a 22.2 km circumference and (c) an 86 GeV per beam collider with a 30.6 km circumference. It is now proposed that the design (c) as discussed in the so-called 'Pink Book' should be used and that the accelerator should be built adjacent to CERN Meyrin. (U.K.)

Probing two-photon decay widths of mesons at energies available at the CERN Large Hadron Collider (LHC)

International Nuclear Information System (INIS)

Bertulani, C. A.

2009-01-01

Meson production cross sections in ultraperipheral relativistic heavy ion collisions at the CERN Large Hadron Collider are revisited. The relevance of meson models and of exotic QCD states is discussed. This study includes states that have not been considered before in the literature.

LEP the large electron-positron project

International Nuclear Information System (INIS)

Schopper, H.

1984-01-01

LEP is an e + e - ring optimized for about 100 GeV per beam. The ring has a circumference of about 26.7 kilometers, and will be 80 to 125 meters deep underground. The existing accelerators, both the PS and the SPS, will be used as injectors. The cost of LEP is 910 million Swiss francs, at 1981 prices. This document describes the outline of the LEP project, especially, in relation to the present CERN site and experimental facilities. The present status of LEP, that is, machine ordering, installation or modification of the existing machines, is explained in the following areas: injection system, magnets, accelerating system, and experimental areas. As for the civil engineering works two international consortia are responsible for the excavation of the tunnel for the main ring. Some photographs are presented to show the status of the civil engineering works. For the transportation of both components and people, a monorail suspended from the ceiling of the tunnel is adopted. The first injection test into an octant is planned in the autumn of 1987, and the first beam all around the LEP will be at the end of 1988. (Aoki, K.)

Beam-related machine protection for the CERN Large Hadron Collider experiments

Directory of Open Access Journals (Sweden)

R. B. Appleby

2010-06-01

Full Text Available The Large Hadron Collider at CERN, Geneva stores 360 MJ per beam of protons at the top machine energy. This amount of energy storage presents a considerable challenge to the machine protection systems designed to protect both the machine and the six LHC experiments. This paper provides an overview of the machine protection systems relevant to the protection of the experiments, and demonstrates their operation and level of protection through a series of injection and stored beam failure scenarios. We conclude that the systems provide sufficient coverage for the protection of the experiments as far as reasonably possible.

Lecture | CERN prepares its long-term future: a 100-km circular collider to follow the LHC? | CERN Globe | 11 March

CERN Multimedia

2015-01-01

Particle physics is a long-term field of research: the LHC was originally conceived in the 1980s, but did not start running until 25 years later. An accelerator unlike any other, it is now just at the start of a programme that is set to run for another 20 years.   Frédérick Bordry. While the LHC programme is already well defined for the next two decades, it is now time to look even further ahead, and so CERN is initiating an exploratory study for a future long-term project centred on a next-generation circular collider with a circumference of 80 to 100 kilometres. A worthy successor to the LHC, whose collision energies will reach 13 TeV in 2015, such an accelerator would allow particle physicists to push the boundaries of knowledge even further. The Future Circular Collider (FCC) programme will focus especially on studies for a hadron collider, like the LHC, capable of reaching unprecedented energies in the region of 100 TeV. Opening with an introduction to the LHC and...

Fast symplectic map tracking for the CERN Large Hadron Collider

Directory of Open Access Journals (Sweden)

Dan T. Abell

2003-06-01

Full Text Available Tracking simulations remain the essential tool for evaluating how multipolar imperfections in ring magnets restrict the domain of stable phase-space motion. In the Large Hadron Collider (LHC at CERN, particles circulate at the injection energy, when multipole errors are most significant, for more than 10^{7} turns, but systematic tracking studies are limited to a small fraction of this total time—even on modern computers. A considerable speedup is expected by replacing element-by-element tracking with the use of a symplectified one-turn map. We have applied this method to the realistic LHC lattice, version 6, and report here our results for various map orders, with special emphasis on precision and speed.

Industrial services at CERN

CERN Multimedia

2002-01-01

The Bulletin looks at industrial services contracts and the real impact of the cost reductions at CERN. The level of industrial services contracts varies from one phase to another. For example, during the dismantling of LEP (photo) it rose substiantially to fall again at the end of dismantling. Industrial services contracts are an important resource for CERN. The level and nature of such contracts changes according to the phase of operation of the Laboratory. A construction phase, as for the LHC, requires a higher level of industrial services contracts compared with a period of normal running. During the operation of LEP, industrial services contracts were thus maintained at a level of 120 MCHF per year. The level rose to 156 MCHF in 2001 to include contracts awarded for dismantling LEP, and fell to about 144 MCHF in 2002 when the dismantling was complete. During the whole LHC construction period, up to 2007, industrial services spending will be stable in the range 135-140 MCHF per year. For the running pe...

Advances in particle physics: the LEP contribution, Conclusions and perspectives

CERN Document Server

Richard, F

2002-01-01

LEP1 precision measurements, combined with LEP2 searches for the Higgs boson, define the framework for future investigations in subatomic physics. In particular they define the energy and the luminosity which are needed at a future e sup + e sup - collider to settle the issue of the origin of mass and to complement the LHC on the various scenarios proposed beyond the Standard Model. (authors)

Hint of a Z' boson from the CERN LEP II data

International Nuclear Information System (INIS)

Gulov, A. V.; Skalozub, V. V.

2007-01-01

The many-parametric fits of the LEP2 data on e + e - →e + e - , μ + μ - , τ + τ - processes are performed with the goal to estimate the signals of the Abelian Z ' boson. Four independent parameters must be fitted, if the derived already low-energy relations between the Z ' couplings to the standard model fermions are taken into consideration. No signals are found when the complete LEP2 data set for these processes is treated. In the fit of the backward bins, the hint at the 1.3σ confidence level is detected. The Z ' couplings to the vector and axial-vector lepton currents are constrained. The comparisons with the one-parameter fits and with the corresponding LEP1 experiments are fulfilled

Heavy flavour production and heavy flavour mixing at the CERN proton-antiproton collider

International Nuclear Information System (INIS)

Eijk, B. van.

1987-01-01

In this thesis some results of the proton-antiproton-collision experiment UA1 with the CERN Super Proton-Antiproton Synchrotron are presented and interpreted. Ch. 1 contians a general introduction to the physics motivations behind the proton-antiproton-collider project, a brief description of the CERN facilities and a summary of collider and UA1 physics achievements. Furthermore the concept of studying heavy flavours via their weak decays into muons is introduced. Ch. 2 gives a brief overview of the UA1 experimental set-up, while those parts of the detector that are relevant for the analysis, presented in this thesis, is discussed in some more detail. Ch. 3 contains a short introduction to, and motivation for the use of Monte Carlo techniques in event simulations, while Ch. 4 describes the framework of the recently developed 'EUROJET' event generator. In Ch. 5 a treatment is given of the theoretical background and concepts like 'quark-mixing' and 'CP-violation' are explained, also other useful definitions and formulae are introduced on which the later analysis of the same-sign to opposite-sign dimuon ratio is built. Data collection and event reconstruction is the subject of Ch. 6, while a detailed comparison between the theoretical models and experimentally obtained distributions is given in Ch. 7. Finally, in Ch. 8 some concluding remarks are made. 182 refs.; 81 figs.; 9 tabs

The Next Linear Collider Design: NLC 2001

Energy Technology Data Exchange (ETDEWEB)

Larsen, Alberta

2001-08-21

Recent studies in elementary particle physics have made the need for an e{sup +}e{sup -} linear collider able to reach energies of 500 GeV and above with high luminosity more compelling than ever. Observations and measurements completed in the last five years at the SLC (SLAC), LEP (CERN), and the Tevatron (FNAL) can be explained only by the existence of at least one particle or interaction that has not yet been directly observed in experiment. The Higgs boson of the Standard Model could be that particle. The data point strongly to a mass for the Higgs boson that is just beyond the reach of existing colliders. This brings great urgency and excitement to the potential for discovery at the upgraded Tevatron early in this decade, and almost assures that later experiments at the LHC will find new physics. But the next generation of experiments to be mounted by the world-wide particle physics community must not only find this new physics, they must find out what it is. These experiments must also define the next important threshold in energy. The need is to understand physics at the TeV energy scale as well as the physics at the 100-GeV energy scale is now understood. This will require both the LHC and a companion linear electron-positron collider.

The Next Linear Collider Design: NLC 2001

International Nuclear Information System (INIS)

Larsen, Alberta

2001-01-01

Recent studies in elementary particle physics have made the need for an e + e - linear collider able to reach energies of 500 GeV and above with high luminosity more compelling than ever. Observations and measurements completed in the last five years at the SLC (SLAC), LEP (CERN), and the Tevatron (FNAL) can be explained only by the existence of at least one particle or interaction that has not yet been directly observed in experiment. The Higgs boson of the Standard Model could be that particle. The data point strongly to a mass for the Higgs boson that is just beyond the reach of existing colliders. This brings great urgency and excitement to the potential for discovery at the upgraded Tevatron early in this decade, and almost assures that later experiments at the LHC will find new physics. But the next generation of experiments to be mounted by the world-wide particle physics community must not only find this new physics, they must find out what it is. These experiments must also define the next important threshold in energy. The need is to understand physics at the TeV energy scale as well as the physics at the 100-GeV energy scale is now understood. This will require both the LHC and a companion linear electron-positron collider

CERN, Geneva

CERN Multimedia

2007-01-01

"The Large Hadron Collider (pages 1-3) is being built at CERN, the European Centre for Nuclear Research near Geneva. CERN offers some extremely exciting opportunities to see "big bang" in action. (1 page)

The performance of the DELPHI hadron calorimeter at LEP

International Nuclear Information System (INIS)

Ajinenko, I.; Beloous, K.; Chudoba, J.

1996-01-01

The DELPHI Hadron Calorimeter was conceived more than ten years ago, as an instrument to measure the energy of hadrons and hadronic jets from e + e - collisions at the CERN collider LEP. In addition it was expected to provide a certain degree of discrimination between pions and muons. The detector is a rather simple and relatively inexpensive device consisting of around 20,000 limited streamer plastic tubes, with inductive pad read-out, embedded in the iron yoke of the 1.2 T DELPHI magnet. Its depth is at minimum 6.6 nuclear interaction lengths. The electronics necessary for the pad readout was designed to have an adequate performance for a reasonable cost. This detector has proved over six years of operation to have an entirely satisfactory performance and great reliability; for example less than 1% of the streamer tubes have failed and electronic problems remain at the per mil level. During the past two years an improvement program has been under way. It has been found possible to use the streamer tubes as strips, hence giving better granularity and particle tracking, by reading out the cathode of individual tubes. The constraints on this were considerable because of the inaccessibility of the detectors in the magnet yoke. However, a cheap and feasible solution has been found. The cathode readout leads to an improved energy resolution, better μ identification, a better π/μ separation and to possibilities of neutral particle separation. The simultaneous anode read-out of several planes of the endcaps of the detector will provide a fast trigger in the forward/backward direction which is an important improvement for LEP200. On the barrel the system will provide a cosmic trigger which is very useful for calibration as counting rates at LEP200 will be very low

Probing Minimal 5D Extensions of the Standard Model From LEP to an $e^{+} e^{-}$ Linear Collider

CERN Document Server

Mück, A; Rückl, R; Mück, Alexander; Pilaftsis, Apostolos; R\\"uckl, Reinhold

2004-01-01

We derive new improved constraints on the compactification scale of minimal 5-dimensional (5D) extensions of the Standard Model (SM) from electroweak and LEP2 data and estimate the reach of an e^+e^- linear collider such as TESLA. Our analysis is performed within the framework of non-universal 5D models, where some of the gauge and Higgs fields propagate in the extra dimension, while all fermions are localized on a S^1/Z_2 orbifold fixed point. Carrying out simultaneous multi-parameter fits of the compactification scale and the SM parameters to the data, we obtain lower bounds on this scale in the range between 4 and 6 TeV. These fits also yield the correlation of the compactification scale with the SM Higgs mass. Investigating the prospects at TESLA, we show that the so-called GigaZ option has the potential to improve these bounds by about a factor 2 in almost all 5D models. Furthermore, at the center of mass energy of 800 GeV and with an integrated luminosity of 10^3 fb^-1, linear collider experiments can p...

LEP - Large Electron Positron Exhibition LEPFest 2000

CERN Multimedia

2000-01-01

The Large Electron-Positron Collider (LEP) is 27 km long. Its four detectors (ALEPH, DELPHI, L3, OPAL) measure precisely what happens in the collisions of electrons and positrons. These conditions only exist-ed in the Universe when it was about 10 -10 sec old.

Gauge bosons and heavy quarks: Proceedings of Summer Institute on Particle Physics

Energy Technology Data Exchange (ETDEWEB)

Hawthorne, J.F. (ed.)

1991-01-01

This report contains papers on the following topics: Z decays and tests of the standard model; future possibilities for LEP; studies of the interactions of electroweak gauge bosons; top quark topics; the next linear collider; electroweak processes in hadron colliders; theoretical topics in B-physics; experimental aspects of B-physics; B-factory storage ring design; rare kaon decays; CP violation in K{sup 0} decays at CERN; recent K{sup 0} decay results from Fermilab E-731; results from LEP on heavy quark physics; review of recent results on heavy flavor production; weak matrix elements and the determination of the weak mixing angles; recent results from CLEO I and a glance at CLEO II data; recent results from ARGUS; neutrino lepton physics with the CHARM 2 detector; recent results from the three TRISTAN experiments; baryon number violation at high energy in the standard model: fact or fiction New particle searches at LEP; review of QCD at LEP; electroweak interactions at LEP; recent results on W physics from the UA2 experiment at the CERN {rho}{bar {rho}} collider; B physics at CDF; and review of particle astrophysics.

Gauge bosons and heavy quarks: Proceedings of Summer Institute on Particle Physics

International Nuclear Information System (INIS)

Hawthorne, J.F.

1991-01-01

This report contains papers on the following topics: Z decays and tests of the standard model; future possibilities for LEP; studies of the interactions of electroweak gauge bosons; top quark topics; the next linear collider; electroweak processes in hadron colliders; theoretical topics in B-physics; experimental aspects of B-physics; B-factory storage ring design; rare kaon decays; CP violation in K 0 decays at CERN; recent K 0 decay results from Fermilab E-731; results from LEP on heavy quark physics; review of recent results on heavy flavor production; weak matrix elements and the determination of the weak mixing angles; recent results from CLEO I and a glance at CLEO II data; recent results from ARGUS; neutrino lepton physics with the CHARM 2 detector; recent results from the three TRISTAN experiments; baryon number violation at high energy in the standard model: fact or fiction? New particle searches at LEP; review of QCD at LEP; electroweak interactions at LEP; recent results on W physics from the UA2 experiment at the CERN ρ bar ρ collider; B physics at CDF; and review of particle astrophysics

Interaction region for crab waist scheme of the Future Electron-Positron Collider (CERN)

CERN Document Server

Bogomyagkov, A

2015-01-01

Design study in CERN of the accelerator that would fit 80-100 km tunnel called Future Circular Colliders (FCC) includes high-luminosity $e^+ e^−$ collider (FCC-ee) with center-of-mass energy from 90 to 350 GeV to study Higgs boson properties and perform precise measurements at the electroweak scale [1–3]. Crab waist interaction region provides collisions with luminosity higher than 2 × 10$^{36}$ cm$^{−2}$ sec$^{−1}$ at beam energy of 45 GeV. The small values of the beta functions at the interaction point and distant final focus lenses are the reasons for high nonlinear chromaticity limiting energy acceptance of the whole ring. The paper describes interaction region for crab waist collision scheme in the FCC-ee, principles of tuning the chromaticity correction section in order to provide large energy acceptance.

First Lecture of Collide@CERN Geneva for Dance and Performance: Gilles Jobin artist in residency and his inspiration partner Joao Pequenao

CERN Multimedia

CERN. Geneva

2012-01-01

CERN, jointly with Canton and City of Geneva, presents the public lecture of Gilles Jobin, the first winner of the Prix Collide@CERN Geneva, residency award for Dance and Performance arts, and his inspiration partner. They will present their work in dance and science at the CERN Globe of Science and Innovation on Wendesday 23 May 2012 at 19h (open doors at 18.30h) Refreshments will be served afterwards. Please reserve your places for you and your friends by contacting merce.monje.cano@cern.ch. +41 22 76 75246 We very much look forward to seeing you there.

France at CERN, 11-14 March 1986. CERN Courier, May 1986, v. 26(4)

Energy Technology Data Exchange (ETDEWEB)

Anon.

1986-05-15

More firms participated in the 1986 'France at CERN' Exhibition than in the previous exhibition in 1983. This year 55 firms, including three Chambers of Commerce and Industry, took part in the exhibition which comprised 34 stands. The choice of firms was approved by the official with responsibility for CERN at the Scientific and Technical Mission of the Ministry of Research and Technology, thereby ensuring that the exhibits corresponded to CERN's immediate needs and in particular to those of LEP.

ECFA Meeting in May: LEP project changes / Backing for HERA / HEP in Europe

International Nuclear Information System (INIS)

Anon.

1980-01-01

The European Committee for Future Accelerators held a Plenary Meeting at CERN on 9 May. The representatives of the Universities and Laboratories in the CERN Member States heard presentations on the latest developments concerning the LEP project at CERN. They supported a recommendation on the HERA project at DESY and they endorsed a detailed report on high energy physics in Europe

ISOLDE 1985-1987: In the shadow of LEP construction

CERN Multimedia

CERN. Geneva

2014-01-01

This report describes my time at CERN from 1985 to 1987. Only very briefly before, ISOLDE was recognized by the CERN Management as a CERN facility and not only as a collaboration performing experiments at the synchrocyclotron (SC). Due to LEP construction the human resources were extremely restricted and I acted in one person as ISOLDE Group Leader, as Coordinator of the Synchrocyclotron, and as person responsible for the ISOLDE Technical Group. In addition, I was responsible for the students of my research groups from Mainz University which were active in laser spectroscopy of neutron-deficient nuclides in the mercury region and in getting ISOLTRAP on the floor and into operation. Due to LEP construction also the financial resources were extremely limited and my requests to the EP Division Leader B. Hyams and to the Director General H. Schopper for financial support for installation of a laser ion source and ISOLTRAP were turned down. Still, I and my students had a lot of fun at ISOLDE and I am very happy th...

Development of high gradient superconducting radio frequency cavities for international linear collider and energy recovery linear accelerator

International Nuclear Information System (INIS)

Saito, Kenji; Furuta, Fumio; Saeki, Takayuki

2009-01-01

Superconducting radio frequency (SRF) cavities were used for storage rings like TRISTAN at KEK, HERA at DESY and LEP-II at CERN in 1990-2000. This technology has been accepted as a common accelerator technology. In August 2004, ITPR recommended an electron/positron linear collider based on SRF technology for the future high energy physics. ICFA accepted the recommendation and named it ILC (International Linear Collider). SRF cavities have a very unique feature due to its very small surface resistance. Energy recovery is another very exciting application. Many laboratories are proposing ERL (Energy Recovery LINAC) as a next bright photon source. In these accelerators, production of SRF cavities with reliably high performance is the most important issue. In this paper the activities of ILC high gradient cavities will be introduced. ERL activity will be briefly presented. (author)

Development of High Gradient Superconducting Radio Frequency Cavities for International Linear Collider and Energy Recovery Linear Accelerator

Science.gov (United States)

Saito, Kenji; Furuta, Fumio; Saeki, Takayuki

Superconducting radio frequency (SRF) cavities were used for storage rings like TRISTAN at KEK, HERA at DESY and LEP-II at CERN in 1990-2000. This technology has been accepted as a common accelerator technology. In August 2004, ITPR recommended an electron/positron linear collider based on SRF technology for the future high energy physics. ICFA accepted the recommendation and named it ILC (International Linear Collider). SRF cavities have a very unique feature due to its very small surface resistance. Energy recovery is another very exciting application. Many laboratories are proposing ERL (Energy Recovery LINAC) as a next bright photon source. In these accelerators, production of SRF cavities with reliably high performance is the most important issue. In this paper the activities of ILC high gradient cavities will be introduced. ERL activity will be briefly presented.

LEP Magnets Get a Second Lease of Life

CERN Multimedia

2001-01-01

Removed one minute, recycled the next! Around 900 yokes from the LEP dipole magnets have been re-used as building material. 906 yokes from the LEP dipole magnets have been incorporated in the foundations of the new Building 954, where they have been used to create the underfloor space and reinforcements. The recycling of LEP is already under way. Over half of CERN's accelerator has been dismantled so far, and parts of its magnets are already beginning a new life: since 16 May, some of the LEP dipole magnet yokes have been re-used as building material. The dipole yokes, the only ones of their kind, are made up of steel plates and layers of concrete sandwiched together, thus forming blocks of reinforced concrete. It would be a painstaking task to separate the basic materials for re-use, which led to the idea of using the yokes intact as reinforcements. 906 LEP yokes have gone into the foundations of the brand-new Building 954 on the Prévessin site. They have been used to build the underfloor space ...

Arrêt du LEP après onze années de recherches de pointe

CERN Multimedia

CERN Press Office. Geneva

2000-01-01

After extended consultation with the appropriate scientific committees, CERN 's Director-General Luciano Maiani announced today that the LEP accelerator had been switched off for the last time. LEP was scheduled to close at the end of September 2000 but tantalising signs of possible new physics led to LEP's run being extended until 2 November. At the end of this extra period, the four LEP experiments had produced a number of collisions compatible with the production of Higgs particles with a mass of around 115 GeV.

Hadron collider physics at UCR

International Nuclear Information System (INIS)

Kernan, A.; Shen, B.C.

1997-01-01

This paper describes the research work in high energy physics by the group at the University of California, Riverside. Work has been divided between hadron collider physics and e + -e - collider physics, and theoretical work. The hadron effort has been heavily involved in the startup activities of the D-Zero detector, commissioning and ongoing redesign. The lepton collider work has included work on TPC/2γ at PEP and the OPAL detector at LEP, as well as efforts on hadron machines

The Spirit counts - People at and around CERN

CERN Multimedia

CERN. Geneva

2014-01-01

After a few biographical remarks I shall concentrate on human aspects which are not covered by official documents, but which are as important to the success of CERN as scientific and technical competence. The approval of LEP, general problems of the project management and the approval of the LEP experiments under conditions never encountered before at CERN will be covered. The special spirit created at CERN based on the competence and solidarity of the CERN staff and its users made it possible to find new ways of successful international collaboration combining competition with cooperation. Career Summary Physics diploma and doctorate from Hamburg University, now Prof. emer.; research assistant at Stockholm Technical University (with Lise Meitner); Cavendish Laboratory UK (with O.R.Frisch); Cornell University (with R.R. Wilson); research in optics, nuclear and elementary particle physics. various professorships in Germany and director of university institutes; Director of DESY, Hamburg, 1973-1980...

France at CERN, 11-14 March 1986. CERN Courier, May 1986, v. 26(4)

International Nuclear Information System (INIS)

Anon.

1986-01-01

More firms participated in the 1986 'France at CERN' Exhibition than in the previous exhibition in 1983. This year 55 firms, including three Chambers of Commerce and Industry, took part in the exhibition which comprised 34 stands. The choice of firms was approved by the official with responsibility for CERN at the Scientific and Technical Mission of the Ministry of Research and Technology, thereby ensuring that the exhibits corresponded to CERN's immediate needs and in particular to those of LEP

Prospects for the Higgs boson in e+e- collisions at LEP 200

International Nuclear Information System (INIS)

Gross, E.; Lellouch, D.; Read, A.L.

1998-05-01

The authors evaluate the combined sensitivity of the four LEP collaborations to exclude or discover the Standard Model Higgs boson with the LEP collider at centre-of-mass energies of 189-200 GeV. It is argued that neighter Standard Model nor the Supersymmetric Higgs search benefits from an upgrade of LEP to its peak centre-of-mass energy (e.g. upgrade 198 GeV to 200 GeV) if this degrades the integrated luminosity by a factor of two or more. 7 refs., 11 figs

Collider phenomenology of technihadrons in the technicolor straw man model

International Nuclear Information System (INIS)

Lane, Kenneth; Mrenna, Stephen

2003-01-01

We discuss the phenomenology of the lightest SU(3) C singlet and nonsinglet technihadrons in the straw man model of low-scale technicolor (TCSM). The technihadrons are assumed to be those arising in top-color-assisted technicolor models in which top-color is broken by technifermion condensates. We improve upon the description of the color-singlet sector presented in our earlier paper introducing the TCSM [K. Lane, Phys. Rev. D 60, 075007 (1999)]. These improvements are most important for subprocess energies well below the masses of the ρ T and ω T vector technihadrons and, therefore, apply especially to e + e - colliders such as CERN LEP and a low-energy linear collider. In the color-octet sector, we consider mixing of the gluon, the coloron V 8 from top-color breaking, and four isosinglet color-octet technirho mesons ρ T8 . We assume, as expected in walking technicolor, that these ρ T8 decay into q-barq, gg, and gπ T final states, but not into π T π T , where π T is a technipion. All the TCSM production and decay processes discussed here are included in the event generator PYTHIA. We present several simulations appropriate for the Fermilab Tevatron collider, and suggest benchmark model lines for further experimental investigation

Exclusive Channels in Photon-Photon Collisions at LEP

OpenAIRE

Braccini, Saverio

2002-01-01

The study of exclusive channels in photon-photon collisions at e+e- colliders allows to investigate the structure and the properties of hadrons in a very clean experimental environment. A concise review of the most recent results obtained at LEP is presented.

Inclusive jet cross-section and a search for quark compositeness at the CERN anti pp Collider

International Nuclear Information System (INIS)

Alitti, J.; Bareyre, P.; Bonamy, P.; Bourliaud, M.; Magneville, C.; Meyer, J.P.; Stirling, A.V.; Zaccone, H.; Ansari, R.; Buskulic, D.; Chollet, J.C.; Fayard, L.; Froidevaux, D.; Gaillard, J.M.; Merkel, B.; Moniez, M.; Parrour, G.; Petroff, P.; Repellin, J.P.; Unal, G.; Blaylock, G.; DiLella, L.; Egan, G.F.; Einsweiler, K.F.; Fumagalli, G.; Gildemeister, O.; Goessling, C.; Goggi, V.G.; Hellman, S.; Hultqvist, K.; Incandela, J.; Jakobs, K.; Jenni, P.; Linssen, L.; Lubrano, P.; Mapelli, L.; Meier, K.; Nessi, M.; Nessi-Tedaldi, F.; Onions, C.; Pal, T.; Parker, M.A.; Poppleton, A.; Rasmussen, L.; Stapnes, S.; Tovey, S.N.; Vercesi, V.; Weidberg, A.R.; Wood, D.R.; Bonesini, M.; Cavalli, D.; Costa, G.; Gianotti, F.; Mandelli, L.; Mazzanti, M.; Perini, L.; Polesello, G.; Borer, K.; Federspiel, A.; Hara, K.; Hugentobler, E.; Moning, R.; Mueller, L.; Pretzl, K.; Schacher, J.; Conta, C.; Dell'Acqua, A.; Ferrari, R.; Fraternali, M.; Livan, M.; Pastore, F.; Pennacchio, E.; Rimoldi, A.; DeWolf, R.S.; Lefebvre, M.; Munday, D.J.; Pentney, J.M.; Singh, S.L.; Wells, P.S.; White, T.O.; Wotton, S.A.; Gruenendahl, S.; Kluge, E.E.; Kurz, N.; Lami, S.; Plothow-Besch, H.; Tsesmelis, E.

1991-01-01

The inclusive jet cross-section has been measured at the CERN anti pp Collider (√s = 630 GeV) as a function of the jet transverse momentum (p T ) and pseudorapidity (η) for p T values up to 180 GeV and for -2 c >825 GeV (95% CL) is set on the quark compositeness scale Λ c . (orig.)

Bounds on new contact interactions from future e+e- colliders

International Nuclear Information System (INIS)

Schrempp, B.; Schrempp, F.; Zeppenfeld, D.; Wisconsin Univ., Madison

1988-01-01

A systematic study of the 'reach' for contact interactions as a probe for new physics at future e + e - colliders is performed. A large energy range is considered, from PETRA/PEP energies at the lower end, via the Z 0 peak (SLC/LEP-I) and LEP-II, up to the TeV regime of a potential future linear e + e - collider. Lower bounds on the compositeness scale Λ for leptons are calculated for Bhabha scattering and μ-pair production using realistic assumptions on the expected luminosities and detector performances. The impact of longitudinal and transverse polarization is studied in detail. The 'reach' corresponding to high rates at the Z 0 peak is compared to the one obtained from running at higher energies. At LEP-II energies, a sensitivity to (lepton) substructure at the level of Λ ≅ 10 TeV is to be expected. At a 2 TeV e + e - collider the sensitivity can be as large as 100 TeV. (orig.)

Attend the lecture of the first artist-scientist inspiration partners of the Collide@CERN programme

CERN Document Server

2012-01-01

Julius Von Bismarck, the first winner of the Prix Ars Electronica Collide@CERN residency award for the digital arts and his science inspiration partner, Dr. James Wells, will present their individual work in art and science at the beginning of the residency on Wednesday 21 March at 18:45 at the Globe of Science and Innovation.   Hands up, this is a photo shoot! Julius Von Bismarck in action. All are welcome! The event will be in English, the common language between the artist and the scientist. To make a reservation for you and any guests, please send an e-mail to merce.monje.cano@cern.ch or call +41 22 76 75 246. For the complete programme of the event, see the official invitation.

Experiments at CERN in 1981

International Nuclear Information System (INIS)

1981-08-01

This report contains the preliminary abstracts of the current experiments at the CERN SPS synchrotron, the anti p colliding beams, the CERN ISR, the CERN PS synchrotron, and the CERN synchrocyclotron. See hints under the relevant topics. (HSI)

The Compact Muon Solenoid Experiment at the Large Hadron Collider The Compact Muon Solenoid Experiment at the Large Hadron Collider

Directory of Open Access Journals (Sweden)

David Delepine

2012-02-01

Full Text Available The Compact Muon Solenoid experiment at the CERN Large Hadron Collider will study protonproton collisions at unprecedented energies and luminosities. In this article we providefi rst a brief general introduction to particle physics. We then explain what CERN is. Thenwe describe the Large Hadron Collider at CERN, the most powerful particle acceleratorever built. Finally we describe the Compact Muon Solenoid experiment, its physics goals,construction details, and current status.El experimento Compact Muon Solenoid en el Large Hadron Collider del CERN estudiarácolisiones protón protón a energías y luminosidades sin precedente. En este artículo presentamos primero una breve introducción general a la física de partículas. Despuésexplicamos lo que es el CERN. Luego describimos el Large Hadron Collider, el más potente acelerador de partículas construido por el hombre, en el CERN. Finalmente describimos el experimento Compact Muon Solenoid, sus objetivos en física, los detalles de su construcción,y su situación presente.

Effects of bulk viscosity and hadronic rescattering in heavy ion collisions at energies available at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider

Science.gov (United States)

Ryu, Sangwook; Paquet, Jean-François; Shen, Chun; Denicol, Gabriel; Schenke, Björn; Jeon, Sangyong; Gale, Charles

2018-03-01

We describe ultrarelativistic heavy ion collisions at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider with a hybrid model using the IP-Glasma model for the earliest stage and viscous hydrodynamics and microscopic transport for the later stages of the collision. We demonstrate that within this framework the bulk viscosity of the plasma plays an important role in describing the experimentally observed radial flow and azimuthal anisotropy simultaneously. We further investigate the dependence of observables on the temperature below which we employ the microscopic transport description.

Hadron collider physics at UCR

Energy Technology Data Exchange (ETDEWEB)

Kernan, A.; Shen, B.C.

1997-07-01

This paper describes the research work in high energy physics by the group at the University of California, Riverside. Work has been divided between hadron collider physics and e{sup +}-e{sup {minus}} collider physics, and theoretical work. The hadron effort has been heavily involved in the startup activities of the D-Zero detector, commissioning and ongoing redesign. The lepton collider work has included work on TPC/2{gamma} at PEP and the OPAL detector at LEP, as well as efforts on hadron machines.

Cryogenic Studies for the Proposed CERN Large Hadron Electron Collider (LHeC)

CERN Document Server

Haug, F

2011-01-01

The LHeC (Large Hadron electron Collider) is a proposed future colliding beam facility for lepton-nucleon scattering particle physics at CERN. A new 60 GeV electron accelerator will be added to the existing 27 km circumference 7 TeV LHC for collisions of electrons with protons and heavy ions. Two basic design options are being pursued. The first is a circular accelerator housed in the existing LHC tunnel which is referred to as the "Ring-Ring" version. Low field normal conducting magnets guide the particle beam while superconducting (SC) RF cavities cooled to 2 K are installed at two opposite locations at the LHC tunnel to accelerate the beams. For this version in addition a 10 GeV re-circulating SC injector will be installed. In total four refrigerators with cooling capacities between 1.2 kW and 3 kW @ 4.5 K are needed. The second option, referred to as the "Linac-Ring" version consists of a race-track re-circulating energy-recovery type machine with two 1 km long straight acceleration sections. The 944 hi...

L3 detector

Energy Technology Data Exchange (ETDEWEB)

Anon.

1992-01-15

This is the final article in the CERN Courier series marking a decade of the four big experiments - Aleph, Delphi, L3 and Opal - at CERN's LEP electron-positron collider. Data-taking started soon after LEP became operational in July 1989, followed by substantial runs in 1990 and 1991. Because of the long lead times involved in today's major physics undertakings, preparations for these four experiments got underway in the early 1980s.

International Workshop on Linear Colliders 2010

CERN Multimedia

CERN. Geneva

2010-01-01

IWLC2010 International Workshop on Linear Colliders 2010ECFA-CLIC-ILC joint meeting: Monday 18 October - Friday 22 October 2010Venue: CERN and CICG (International Conference Centre Geneva, Switzerland) This year, the International Workshop on Linear Colliders organized by the European Committee for Future Accelerators (ECFA) will study the physics, detectors and accelerator complex of a linear collider covering both CLIC and ILC options.Contact Workshop Secretariat  IWLC2010 is hosted by CERN

ColliderBit. A GAMBIT module for the calculation of high-energy collider observables and likelihoods

Energy Technology Data Exchange (ETDEWEB)

Balazs, Csaba [Monash University, School of Physics and Astronomy, Melbourne, VIC (Australia); Australian Research Council Centre of Excellence for Particle Physics at the Tera-scale (Australia); Buckley, Andy [University of Glasgow, SUPA, School of Physics and Astronomy, Glasgow (United Kingdom); Dal, Lars A.; Krislock, Abram; Raklev, Are [University of Oslo, Department of Physics, Oslo (Norway); Farmer, Ben [AlbaNova University Centre, Oskar Klein Centre for Cosmoparticle Physics, Stockholm (Sweden); Jackson, Paul; Murnane, Daniel; White, Martin [Australian Research Council Centre of Excellence for Particle Physics at the Tera-scale (Australia); University of Adelaide, Department of Physics, Adelaide, SA (Australia); Kvellestad, Anders [NORDITA, Stockholm (Sweden); Putze, Antje [Universite de Savoie, LAPTh, Annecy-le-Vieux (France); Rogan, Christopher [Harvard University, Department of Physics, Cambridge, MA (United States); Saavedra, Aldo [Australian Research Council Centre of Excellence for Particle Physics at the Tera-scale (Australia); The University of Sydney, Faculty of Engineering and Information Technologies, Centre for Translational Data Science, School of Physics, Sydney, NSW (Australia); Scott, Pat [Imperial College London, Blackett Laboratory, Department of Physics, London (United Kingdom); Weniger, Christoph [University of Amsterdam, GRAPPA, Institute of Physics, Amsterdam (Netherlands); Collaboration: The GAMBIT Scanner Workgroup

2017-11-15

We describe ColliderBit, a new code for the calculation of high energy collider observables in theories of physics beyond the Standard Model (BSM). ColliderBit features a generic interface to BSM models, a unique parallelised Monte Carlo event generation scheme suitable for large-scale supercomputer applications, and a number of LHC analyses, covering a reasonable range of the BSM signatures currently sought by ATLAS and CMS. ColliderBit also calculates likelihoods for Higgs sector observables, and LEP searches for BSM particles. These features are provided by a combination of new code unique toColliderBit, and interfaces to existing state-of-the-art public codes. ColliderBit is both an important part of the GAMBIT framework for BSM inference, and a standalone tool for efficiently applying collider constraints to theories of new physics. (orig.)

People and things. CERN Courier, April 1982, v. 22(3)

International Nuclear Information System (INIS)

Anon.

1982-01-01

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events. Now that the LEP electron-positron collider project is under way at CERN, decisions have been taken on the management of the machine construction and on preparations for the experimental programme.In bad shape with the 1982 budget inherited from the previous administration, the US high energy physics funding has been reviewed by the Reagan administration in the light of the current US economic situation. In the meantime the US High Energy Physics Advisory Panel (HEPAP) formed a committee under the chairmanship of George Trilling to look at the implications of different possible funding levels for the long range planning of US high energy physics. Work on the 3.8 km circumference ISABELLE tunnel began in 1978 and is now largely complete. The Tevatron II project at Fermilab to convert the Energy Saver to full 1000 GeV experimental operation has received US government authorization. Some 150 physicists met at SLAC recently to discuss reports on the experimental prospects at the SLAC Linear Collider (SLC). This meeting concluded the first phase of study for the SLC physics programme. More news from the CESR electron-positron ring at Cornell to update our recent story. After further operation with the new mini-beta insertions, normal operating luminosity has been improved by a factor of three

CERN 's large hadron collider : Radiation protection aspects of design and commissioning

International Nuclear Information System (INIS)

Forkel-Wirth, Doris; Brugger, Markus; Menzel, Hans; Roesler, Stefan; Vincke, Heinz; Vincke, Helmut

2008-01-01

Full text: CERN, the world's largest particle physics laboratory provides high energy hadron beams for experiments exploring matter. For this purpose various accelerators are operated and in 2008 the last link will be added to the accelerator chain: beam will be injected into CERN 's new 'flagship', the Large Hadron Collider (LHC). From then on high energy physics experiments will exploit the LHC 's colliding beams of protons and lead ions with a center of mass energy of 14 TeV and 1150 TeV, respectively. Radiation Protection aspects were taken into account during the whole duration of the design phase. Conservative design constraints were defined in 1996; some years later some of them, in particular with respect to the dose to occupational exposed workers, had to be readjusted to account for the latest development in CERN 's radiation protection rules and regulations. Numerous radiation protection studies had been performed to ensure a lay-out of the machine and its experiments in compliance with these constraints. These studies assessed all radiation risks related to the various beam-operation modes of the accelerator. In all cases external exposure was identified as the major risk: due to high energetic, mixed radiation fields during beam-on and due to beta and gamma radiation fields caused by induced radioactivity during beam-off. Counter measures were implemented like an optimized beam operation to limit beam losses, installation of thick shielding, prohibition of access to the major part of the LHC underground areas during beam-operation and optimization of the equipment and its handling during maintenance and repair. Detailed Monte Carlo simulations were performed to derive from the various beam loss scenarios the dose rates the workers will be exposed to. Individual and collective doses were projected based on the calculations and the maintenance scenarios provided by the teams concerned. In an iterative way the lay-out of the various regions were optimized

Workshop on physics at future accelerators

International Nuclear Information System (INIS)

1987-01-01

A workshop took place at La Thuile and at CERN in January 1987 to study the physics potential of three types of particle collider with energies in the TeV region, together with the feasibility of experiments with them. The machines were: a large hadron collider (LHC) placed in the LEP tunnel at CERN, with a total proton-proton centre-of-mass energy of about 16 TeV; an electron-proton collider, using the LHC and LEP, with a centre-of-mass energy in the range 1.3 TeV to 1.8 TeV; and an electron-positron linear collider with centre-of-mass energy about 2 TeV. The summary talks given at CERN by the conveners of the study groups are contained in volume I of the proceedings; the present volume is devoted to the contributions from the participants at La Thuile. These give details of the studies carried out on the new phenomena which might be observed at the new machines and the technical feasibility of possible experiments. (orig.)

People and things. CERN Courier, Oct 1995, v. 35(7)

International Nuclear Information System (INIS)

Anon.

1995-01-01

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events: Gentner-Kastler Prize: T he prestigious Gentner-Kastler Prize, jointly awarded by the French and German Physical Societies, goes this year to Walter Schmidt-Parzefall of DESY, formerly leader of the Argus group at the DORIS electron-positron collider at the DESY Laboratory Hamburg, which has made many significant contributions to heavy quark spectroscopy. Subsequently he joined Hamburg University, and has recently played a prominent role in establishing the HERA-B experiment at DESY's HERA electron-proton collider. Before working at DESY, Schmidt-Parzefall spent some time at CERN's Intersecting Storage Rings.; Thirty ISR years: A discreet lunch event at CERN marked the 30th anniversary of the historic decision to go ahead with the Intersecting Storage Rings (ISR) at CERN. Among those present were Victor Weisskopf, CERN's Director General at the time, and Mervyn Hine, responsible for CERN's longterm planning under Weisskopf. The ISR, the world's first proton collider, came into operation in 1971, ahead of schedule, but was shut down in 1984, also ahead of schedule, as part of the bid to divert funds to LEP construction. The ISR, which used the idea of particle stacking to build up the stored beam intensity, was long regarded as a masterpiece of accelerator building, and blazed a trail for CERN's future accelerator projects. Many CERN specialists cut their accelerator teeth at the ISR.; ICTP Dirac Medal: The International Centre for Theoretical Physics (ICTP), Trieste, is awarding its 1995 Dirac Medal to Michael Berry of Bristol for his discovery of the non-integrable phase that arises in adiabatic processes in quantum theory. This effect was first detected in 1986 in an optics experiment by Tomita and Chiao in which the rotation of the polarization plane of a

People and things. CERN Courier, January-February 1982, v. 22(1)

International Nuclear Information System (INIS)

Anon.

1982-01-01

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events. The project to build a large electron- positron storage ring, LEP, at CERN already had the backing of the twelve CERN Member States, but three votes remained subject to conditions. At a CERN Council meeting in December this 'ad referendum' was lifted by the Netherlands, Norway and Sweden. The LEP project thus has the unconditional support of all Member States.New members of the IUPAP International Commission on Particles and Fields have been elected. The International Committee for Future Accelerators (ICFA) held its sixth meeting at Protvino, USSR, on the occasion of the ICFA Workshop on very high field (10 Tesla) superconducting magnets

Production of high mass eν and e+e- pairs in the UA2 experiment at the CERN anti pp collider

International Nuclear Information System (INIS)

Schacher, J.

1984-01-01

We present new results on intermediate vector boson production at the CERN anti pp collider. A comparison is made with the predictions of the standard model of the unified electroweak Glashow-Salam-Weinberg theory. (orig.)

CERN: Council Session

International Nuclear Information System (INIS)

Anon.

1983-01-01

The coming years will be dominated by the building of LEP and the preparation for the four approved experiments. Construction of the underground ring tunnel to house the electron-positron collider will begin very soon and about half of the contracts for machine components have been placed. The four experiments, ALEPH, DELPHI, L3 and OPAL have been designed and costed in detail. Over 900 physicists are involved and contracts with the participating research centres are being drawn up specifying responsibilities and financial commitments. Thus the whole timescale and expenditure profile of the LEP project is now much clearer

COLLIDE Pro Helvetia Award

CERN Multimedia

2016-01-01

The COLLIDE Pro Helvetia Award is run in partnership with Pro Helvetia, giving the opportunity to Swiss artists to do research at CERN for three months.   From left to right: Laura Perrenoud, Marc Dubois and Simon de Diesbach. The photo shows their VR Project, +2199. Fragment.In are the winning artists of COLLIDE Pro Helvetia. They came to CERN for two months in 2015, and will now continue their last month in the laboratory. Fragment.In is a Swiss based interaction design studio. They create innovative projects, interactive installations, video and game design. Read more about COLLIDE here.

Quench protection diodes for the large hadron collider LHC at CERN

International Nuclear Information System (INIS)

Hagedorn, D.; Naegele, W.

1992-01-01

For the quench protection of the main ring dipole and quadrupole magnets for the proposed Large Hadron Collider at CERN two lines of approach have been pursued for the realization of a suitable high current by-pass element and liquid helium temperature. Two commercially available diodes of the HERA type connected in parallel can easily meet the requirements if a sufficient good current sharing is imposed by current balancing elements. Design criteria for these current balancing elements are derived from individual diode characteristics. Single diode elements of thin base region, newly developed in industry, have been successfully tested. The results are promising and, if the diodes can be made with reproducible characteristics, they will provide the preferred solution especially in view of radiation hardness

The Next Linear Collider: NLC2001

International Nuclear Information System (INIS)

Burke, D.

2002-01-01

Recent studies in elementary particle physics have made the need for an e + e - linear collider able to reach energies of 500 GeV and above with high luminosity more compelling than ever [1]. Observations and measurements completed in the last five years at the SLC (SLAC), LEP (CERN), and the Tevatron (FNAL) can be explained only by the existence of at least one particle or interaction that has not yet been directly observed in experiment. The Higgs boson of the Standard Model could be that particle. The data point strongly to a mass for the Higgs boson that is just beyond the reach of existing colliders. This brings great urgency and excitement to the potential for discovery at the upgraded Tevatron early in this decade, and almost assures that later experiments at the LHC will find new physics. But the next generation of experiments to be mounted by the world-wide particle physics community must not only find this new physics, they must find out what it is. These experiments must also define the next important threshold in energy. The need is to understand physics at the TeV energy scale as well as the physics at the 100-GeV energy scale is now understood. This will require both the LHC and a companion linear electron-positron collider. A first Zeroth-Order Design Report (ZDR) [2] for a second-generation electron-positron linear collider, the Next Linear Collider (NLC), was published five years ago. The NLC design is based on a high-frequency room-temperature rf accelerator. Its goal is exploration of elementary particle physics at the TeV center-of-mass energy, while learning how to design and build colliders at still higher energies. Many advances in accelerator technologies and improvements in the design of the NLC have been made since 1996. This Report is a brief update of the ZDR

The Next Linear Collider: NLC2001

Energy Technology Data Exchange (ETDEWEB)

D. Burke et al.

2002-01-14

Recent studies in elementary particle physics have made the need for an e{sup +}e{sup -} linear collider able to reach energies of 500 GeV and above with high luminosity more compelling than ever [1]. Observations and measurements completed in the last five years at the SLC (SLAC), LEP (CERN), and the Tevatron (FNAL) can be explained only by the existence of at least one particle or interaction that has not yet been directly observed in experiment. The Higgs boson of the Standard Model could be that particle. The data point strongly to a mass for the Higgs boson that is just beyond the reach of existing colliders. This brings great urgency and excitement to the potential for discovery at the upgraded Tevatron early in this decade, and almost assures that later experiments at the LHC will find new physics. But the next generation of experiments to be mounted by the world-wide particle physics community must not only find this new physics, they must find out what it is. These experiments must also define the next important threshold in energy. The need is to understand physics at the TeV energy scale as well as the physics at the 100-GeV energy scale is now understood. This will require both the LHC and a companion linear electron-positron collider. A first Zeroth-Order Design Report (ZDR) [2] for a second-generation electron-positron linear collider, the Next Linear Collider (NLC), was published five years ago. The NLC design is based on a high-frequency room-temperature rf accelerator. Its goal is exploration of elementary particle physics at the TeV center-of-mass energy, while learning how to design and build colliders at still higher energies. Many advances in accelerator technologies and improvements in the design of the NLC have been made since 1996. This Report is a brief update of the ZDR.

Carlo Rubbia, former CERN Director-General, appointed Senator for life by the President of Italy.

CERN Multimedia

Antonella Del Rosso

2013-01-01

Today, the President of the Italian Republic Giorgio Napolitano appointed four new senators for life: the music director and conductor “maestro” Claudio Abbado, the neuroscientist Professor Elena Cattaneo, the renowned architect Renzo Piano and Professor Carlo Rubbia, who was CERN Director-General from 1989 to 1993.   Carlo Rubbia during his talk for the discovery of the W particle in 1983. In 1984, Carlo Rubbia, then head of the UA1 collaboration, was awarded the Nobel Prize in Physics, together with Simon van der Meer, for the discovery of the W and Z particles – at that time two important missing components of the Standard Model. During his term of office as Director-General, the Large Electron Positron collider was inaugurated and the four LEP experiments produced their first results. He also mounted the case for the new Large Hadron Collider, which in 2012 led to the discovery of a Higgs boson. In 1993, the last year of his mandate, the World Wide Web proto...

CERN collider homes in on Higgs boson

CERN Multimedia

Abbott, A

1999-01-01

Last week LEP was pushed beyond its design limits when the electron and positron beams acheived energies of 200 GeV. According to some physicists, this level could be high enough to detect the Higgs boson (4 paragraphs).

CREATIVE COLLISIONS: ARTS @CERN

CERN Multimedia

CERN. Geneva

2012-01-01

In 2000, CERN hosted Signatures of the Invisible – one of the landmark initiatives in arts and science. In 2012, CERN is now initiating its own science/arts programme Collide@CERN in different arts disciplines. The first of these is in digital arts, and the international competition to find the winning artist is called the Prix Ars Electronica Collide@CERN. It was announced September 2011 at CERN’s first collaboration with an international arts festival – Ars Electronica in Linz. The competition attracted over 395 entries from 40 countries around the world. The winning artist, Julius Von Bismarck, will begin his two month residency here at CERN next month. Ariane Koek who leads on this initiative, discusses the residency programme, as well as the background about Art@CERN. History has shown that particle physics and the arts are great inspiration partners. The publication of the paper by Max Planck which gave birth to quantum mechanics as well as those by Einstein, heavily influenced some of the grea...

2015 CERN-Fermilab HCP Summer School

CERN Multimedia

2015-01-01

CERN and Fermilab are jointly offering a series of "Hadron Collider Physics Summer Schools", to prepare young researchers for these exciting times. The school has alternated between CERN and Fermilab, and will return to CERN for the tenth edition, from 24 June to 3 July 2015. The CERN-Fermilab Hadron Collider Physics Summer School is an advanced school targeted particularly at young postdocs and senior PhD students working towards the completion of their thesis project, in both Experimental High Energy Physics (HEP) and phenomenology. Lecture Topics include: Statistics in HEP, Heavy Flavour, Heavy Ion, Standard Model, Higgs searches and measurements, BSM theory, BSM searches, Top physics, QCD and Monte Carlos, Accelerators, Detectors for the future, Trigger and DAQ, Dark Matter Astroparticle, and two special lectures on Future Colliders, and 20 years after the top discovery. Calendar and Details: Mark your calendar for  24 June - 3 July 2015, when CERN will welcome students to t...

People and things. CERN Courier, Mar 1984, v. 24(2)

Energy Technology Data Exchange (ETDEWEB)

Anon.

1984-03-15

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events. Some time ago, Wolfgang ('Pief') Panofsky, Director of SLAC since 1961 and one of the prime movers behind both the famous two-mile electron linac and the Laboratory itself, announced his intention to step down in 1984. Immediately a search began for a worthy successor. Carlo Rubbia, leader of the UA 1 experiment at CERN which last year discovered the W and Z particles, was named by the US science magazine 'Discover' as its 1983 'Scientist of the Year'. A CERN-ECFA Workshop to study the feasibility of hadron colliders which it might at some time in the future be possible to install in the LEP tunnel, is to be held at the University of Lausanne from 21-24 March. Fermilab will host the 1984 US Summer School on High Energy Particle Accelerators from 13-24 August - the fourth in this series of summer schools.The 1984 CERN School of Computing, the eighth in the biennial series, is being organized in collaboration with the Instituto Estudios Energeticos (Junta de Energia Nuclear, Madrid) and the Facultad de Informatica, Barcelona, and will be held from 9-22 September at Aiguablava, Spain. The 1984 Users' Meeting of the High Energy Discussion Group (HEDG) at Brookhaven on 29-31 March will include a Workshop on the possible physics from an improved Alternating Gradient Synchrotron.

L3 detector

International Nuclear Information System (INIS)

Anon.

1992-01-01

This is the final article in the CERN Courier series marking a decade of the four big experiments - Aleph, Delphi, L3 and Opal - at CERN's LEP electron-positron collider. Data-taking started soon after LEP became operational in July 1989, followed by substantial runs in 1990 and 1991. Because of the long lead times involved in today's major physics undertakings, preparations for these four experiments got underway in the early 1980s

The LHC timeline: a personal recollection (1980-2012)

Science.gov (United States)

Maiani, Luciano; Bonolis, Luisa

2017-12-01

The objective of this interview is to study the history of the Large Hadron Collider in the LEP tunnel at CERN, from first ideas to the discovery of the Brout-Englert-Higgs boson, seen from the point of view of a member of CERN scientific committees, of the CERN Council and a former Director General of CERN in the years of machine construction.

CERN

CERN Multimedia

2007-01-01

"Geat ready for the mother of all particle accelerator: the Large Hadron Collider (LHC), nearing completion at CERN, the International particle physics lab headquartered in Geneva, Switzerland." (1 paragraph)

Installation and management of the SPS and LEP control system computers

International Nuclear Information System (INIS)

Bland, Alastair

1994-01-01

Control of the CERN SPS and LEP accelerators and service equipment on the two CERN main sites is performed via workstations, file servers, Process Control Assemblies (PCAs) and Device Stub Controllers (DSCs). This paper describes the methods and tools that have been developed to manage the file servers, PCAs and DSCs since the LEP startup in 1989. There are five operational DECstation 5000s used as file servers and boot servers for the PCAs and DSCs. The PCAs consist of 90 SCO Xenix 386 PCs, 40 LynxOS 486 PCs and more than 40 older NORD 100s. The DSCs consist of 90 OS-968030 VME crates and 10 LynxOS 68030 VME crates. In addition there are over 100 development systems. The controls group is responsible for installing the computers, starting all the user processes and ensuring that the computers and the processes run correctly. The operators in the SPS/LEP control room and the Services control room have a Motif-based X window program which gives them, in real time, the state of all the computers and allows them to solve problems or reboot them. ((orig.))

Gilles Jobin Collide@CERN - Strangels Intervention

CERN Multimedia

Gregory Batardon

2012-01-01

STRANGELS Cie Gilles Jobin. Site specific choreographic intervention inside the CERN's library. Three strangels on a migration to another dimension rest at the CERN's library. Strangels need food for thoughts. Do not pay attention to them they are only strangels. Dancers : Ruth Childs, Susana Panadès Diaz, Gilles Jobin

Study of cosmic ray events with high muon multiplicity using the ALICE detector at the CERN Large Hadron Collider

Energy Technology Data Exchange (ETDEWEB)

Collaboration: ALICE Collaboration

2016-01-01

ALICE is one of four large experiments at the CERN Large Hadron Collider near Geneva, specially designed to study particle production in ultra-relativistic heavy-ion collisions. Located 52 meters underground with 28 meters of overburden rock, it has also been used to detect muons produced by cosmic ray interactions in the upper atmosphere. In this paper, we present the multiplicity distribution of these atmospheric muons and its comparison with Monte Carlo simulations. This analysis exploits the large size and excellent tracking capability of the ALICE Time Projection Chamber. A special emphasis is given to the study of high multiplicity events containing more than 100 reconstructed muons and corresponding to a muon areal density ρ{sub μ} > 5.9 m{sup −2}. Similar events have been studied in previous underground experiments such as ALEPH and DELPHI at LEP. While these experiments were able to reproduce the measured muon multiplicity distribution with Monte Carlo simulations at low and intermediate multiplicities, their simulations failed to describe the frequency of the highest multiplicity events. In this work we show that the high multiplicity events observed in ALICE stem from primary cosmic rays with energies above 10{sup 16} eV and that the frequency of these events can be successfully described by assuming a heavy mass composition of primary cosmic rays in this energy range. The development of the resulting air showers was simulated using the latest version of QGSJET to model hadronic interactions. This observation places significant constraints on alternative, more exotic, production mechanisms for these events.

Proceedings of the workshop on physics at future accelerators

International Nuclear Information System (INIS)

1987-01-01

A workshop took place at La Thuile and at CERN in January 1987 to study the physics potential of three types of particle collider with energies in the TeV region, together with the feasibility of experiments with them. The machines were: A Large Hadron Collider (LHC) placed in the LEP tunnel at CERN, with a total proton-proton centre-of-mass energy of about 16 TeV; an electron-proton collider, using the LHC and LEP, with a centre-of-mass energy in the range 1.3 TeV to 1.8 TeV; and an electron-positron linear collider with centre-of-mass energy about 2 TeV. This volume of the proceedings contains summary talks given at CERN by the conveners of the study groups. They cover the possibilities for discovery of new phenomena anticipated in the energy region up to the order of a TeV in the centre of mass of colliding partons, or of the electron and positron. Also discussed are the limits of current technology in the construction of particle-detector systems suitable for use at these energies, and especially in the high event rates provided by a proton-proton collider of luminosity 10 33 cm -2 s -1 or more. (orig.)

Precision Experiments at LEP

CERN Document Server

de Boer, Wim

2015-01-01

The Large Electron Positron Collider (LEP) established the Standard Model (SM) of particle physics with unprecedented precision, including all its radiative corrections. These led to predictions for the masses of the top quark and Higgs boson, which were beautifully confirmed later on. After these precision measurements the Nobel Prize in Physics was awarded in 1999 jointly to 't Hooft and Veltman "for elucidating the quantum structure of electroweak interactions in physics". Another hallmark of the LEP results were the precise measurements of the gauge coupling constants, which excluded unification of the forces within the SM, but allowed unification within the supersymmetric extension of the SM. This increased the interest in Supersymmetry (SUSY) and Grand Unified Theories, especially since the SM has no candidate for the elusive dark matter, while Supersymmetry provides an excellent candidate for dark matter. In addition, Supersymmetry removes the quadratic divergencies of the SM and {\\it predicts} the Hig...

Heavy-ion physics with the ALICE experiment at the CERN Large Hadron Collider.

Science.gov (United States)

Schukraft, J

2012-02-28

After close to 20 years of preparation, the dedicated heavy-ion experiment A Large Ion Collider Experiment (ALICE) took first data at the CERN Large Hadron Collider (LHC) accelerator with proton collisions at the end of 2009 and with lead nuclei at the end of 2010. After a short introduction into the physics of ultra-relativistic heavy-ion collisions, this article recalls the main design choices made for the detector and summarizes the initial operation and performance of ALICE. Physics results from this first year of operation concentrate on characterizing the global properties of typical, average collisions, both in proton-proton (pp) and nucleus-nucleus reactions, in the new energy regime of the LHC. The pp results differ, to a varying degree, from most quantum chromodynamics-inspired phenomenological models and provide the input needed to fine tune their parameters. First results from Pb-Pb are broadly consistent with expectations based on lower energy data, indicating that high-density matter created at the LHC, while much hotter and larger, still behaves like a very strongly interacting, almost perfect liquid.

Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

CERN Document Server

Bruce, R.; Boccone, V.; Bracco, C.; Brugger, M.; Cauchi, M.; Cerutti, F.; Deboy, D.; Ferrari, A.; Lari, L.; Marsili, A.; Mereghetti, A.; Mirarchi, D.; Quaranta, E.; Redaelli, S.; Robert-Demolaize, G.; Rossi, A.; Salvachua, B.; Skordis, E.; Tambasco, C.; Valentino, G.; Weiler, T.; Vlachoudis, V.; Wollmann, D.

2014-08-21

The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010--2013, the LHC was routinely storing protons at 3.5--4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An un-controlled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multi-stage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the co...

Fault Tracking of the Superconducting Magnet System at the CERN Large Hadron Collider

CERN Document Server

Griesemer, Tobias

2016-03-25

The Large Hadron Collider (LHC) at CERN is one of the most complex machines ever built. It is used to explore the mysteries of the universe by reproducing conditions of the big bang. High energy particles are collide in particle detectors and as a result of the collision process secondary particles are created. New particles could be discovered during this process. The operation of such a machine is not straightforward and is subject to many different types of failures. A model of LHC operation needs to be defined in order to understand the impact of the various failures on availability. As an example a typical operational cycle is described: the beams are first injected, then accelerated, and finally brought into collisions. Under nominal conditions, beams should be in collision (so-called ‘stable beams’ period) for about 10 hours and then extracted onto a beam dump block. In case of a failure, the Machine Protection Systems ensure safe extraction of the beams. From the experience in LHC Run 1 (2009 - 20...

Building, running and dismantling the world's largest scientific instrument with the same database tools

CERN Document Server

Billen, R; CERN. Geneva. SPS and LHC Division

2001-01-01

Many people have heard of CERN, the European Organisation for Nuclear Research, and its enormous scientific masterpiece LEP, the Large Electron Positron collider. This is a 27-kilometer long particle accelerator designed to peek deeply inside the structure of matter in the framework of fundamental research. Despite the millions of Internet users, few of them know that the World Wide Web was invented at CERN in 1989, the same year that LEP was commissioned. Even fewer people know that CERN was among the first European organisations to have purchased the Oracle RDBMS back in 1983 and effectively put it in use for mission critical data management applications. Since that date, Oracle databases have been used extensively at CERN and in particular for technical and scientific data. This paper gives an overview of the use of Oracle throughout the lifecycle of CERN's flagship: the construction, exploitation and dismantling of LEP.

CERN: The best of the bunch

Energy Technology Data Exchange (ETDEWEB)

Gagliardi, F.

1992-10-15

As other factors governing the electron-positron collision rate in CERN's LEP 27-kilometre storage ring reach their limit, one way of coaxing the collision rate higher is to increase the number of bunches stored in the ring.

LEP Radio Frequency Copper Cavity

CERN Multimedia

The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

Large Area Silicon Tracking Detectors with Fast Signal Readout for the Large Hadron Collider (LHC) at CERN

CERN Document Server

Köstner, S

2005-01-01

The Standard Model of elementary particles, which is summarized briefly in the second chapter, incorporates a number of successful theories to explain the nature and consistency of matter. However not all building blocks of this model could yet be tested by experiment. To confirm existing theories and to improve nowadays understanding of matter a new machine is currently being built at CERN, the Large Hadron Collider (LHC), described in the third chapter. LHC is a proton-proton collider which will reach unprecedented luminosities and center of mass energies. Five experiments are attached to it to give answers to questions like the existence of the Higgs meson, which allows to explain the mass content of matter, and the origin of CP-violation, which plays an important role in the baryogenesis of the universe. Supersymmetric theories, proposing a bosonic superpartner for each fermion and vice versa, will be tested. By colliding heavy ions, high energy and particle densities can be achieved and probed. This stat...

Superconductive technologies for the Large Hadron collider at CERN

CERN Document Server

Rossi, L

2000-01-01

The Large Hadron Collider (LHC) project is the largest plant based on superconductivity and cryogenics: 27 km of tunnel filled with superconducting magnets and other equipment that will be kept at 1.9 K. The dipole magnets have to generate a minimum magnetic field of 8.3 T to allow collisions of proton beams at an energy of 14 TeV in the centre of mass. The construction of LHC started in 1997 at CERN in Geneva and required 10 years of research and development on fine- filament NbTi superconducting wires and cables, on magnet technology and on He-II refrigerators. In particular the project needs the production of about 1000 tons of high-homogeneity NbTi with current densities of more than 2000 A mm/sup -2/ at 9 T and 1.9 K, with tight control also of all other cable properties such as magnetization, interstrand resistance and copper resistivity. The paper describes the main dipole magnets and reviews the most significant steps in the research and development, focusing on the issues related to the conductor, to...

Cryogenics for CERN experiments past, present and future

CERN Document Server

Bremer, J; Delikaris, D; Delruelle, N; Kesseler, G; Passardi, Giorgio; Rieubland, Jean Michel; Tischhauser, Johann; Haug, F

1997-01-01

Use of cryogenics at CERN was originated (in the 1960s) by bubble chambers and the associated s.c. solenoids. Complex cryoplants were installed to provide cooling at LH2 and LHe temperatures. Continuity (in the 1970s) in He cryogenics for experiments was provided by spectrometer magnets for fixed target physics of the SPS accelerator. More recently (in the 1980s), large "particle-transparent" s.c. solenoids for collider experiments (LEP) have been built demanding new cryoplants. The LHC experiments (in the 2000s) will continue the tradition with s.c. dipoles (ALICE and LHCb), solenoids (CMS, ATLAS) and toroids (ATLAS) of unusual size. Cryogenics for experiments using noble liquids follows the same trend since the development (in the 1970s) of the first shower LAr detectors. A LKr calorimeter (about 10 m3) will be operated in 1996 and the ATLAS experiment foresees a set of three huge LAr calorimeters (almost 90 m3 total volume of liquid) to be installed underground.

Ion colliders

Energy Technology Data Exchange (ETDEWEB)

Fischer, W.

2011-12-01

Ion colliders are research tools for high-energy nuclear physics, and are used to test the theory of Quantum Chromo Dynamics (QCD). The collisions of fully stripped high-energy ions create matter of a temperature and density that existed only microseconds after the Big Bang. Ion colliders can reach higher densities and temperatures than fixed target experiments although at a much lower luminosity. The first ion collider was the CERN Intersecting Storage Ring (ISR), which collided light ions [77Asb1, 81Bou1]. The BNL Relativistic Heavy Ion Collider (RHIC) is in operation since 2000 and has collided a number of species at numerous energies. The CERN Large Hadron Collider (LHC) started the heavy ion program in 2010. Table 1 shows all previous and the currently planned running modes for ISR, RHIC, and LHC. All three machines also collide protons, which are spin-polarized in RHIC. Ion colliders differ from proton or antiproton colliders in a number of ways: the preparation of the ions in the source and the pre-injector chain is limited by other effects than for protons; frequent changes in the collision energy and particle species, including asymmetric species, are typical; and the interaction of ions with each other and accelerator components is different from protons, which has implications for collision products, collimation, the beam dump, and intercepting instrumentation devices such a profile monitors. In the preparation for the collider use the charge state Z of the ions is successively increased to minimize the effects of space charge, intrabeam scattering (IBS), charge change effects (electron capture and stripping), and ion-impact desorption after beam loss. Low charge states reduce space charge, intrabeam scattering, and electron capture effects. High charge states reduce electron stripping, and make bending and acceleration more effective. Electron stripping at higher energies is generally more efficient. Table 2 shows the charge states and energies in the

Ion colliders

International Nuclear Information System (INIS)

Fischer, W.

2010-01-01

Ion colliders are research tools for high-energy nuclear physics, and are used to test the theory of Quantum Chromo Dynamics (QCD). The collisions of fully stripped high-energy ions create matter of a temperature and density that existed only microseconds after the Big Bang. Ion colliders can reach higher densities and temperatures than fixed target experiments although at a much lower luminosity. The first ion collider was the CERN Intersecting Storage Ring (ISR), which collided light ions (77Asb1, 81Bou1). The BNL Relativistic Heavy Ion Collider (RHIC) is in operation since 2000 and has collided a number of species at numerous energies. The CERN Large Hadron Collider (LHC) started the heavy ion program in 2010. Table 1 shows all previous and the currently planned running modes for ISR, RHIC, and LHC. All three machines also collide protons, which are spin-polarized in RHIC. Ion colliders differ from proton or antiproton colliders in a number of ways: the preparation of the ions in the source and the pre-injector chain is limited by other effects than for protons; frequent changes in the collision energy and particle species, including asymmetric species, are typical; and the interaction of ions with each other and accelerator components is different from protons, which has implications for collision products, collimation, the beam dump, and intercepting instrumentation devices such a profile monitors. In the preparation for the collider use the charge state Z of the ions is successively increased to minimize the effects of space charge, intrabeam scattering (IBS), charge change effects (electron capture and stripping), and ion-impact desorption after beam loss. Low charge states reduce space charge, intrabeam scattering, and electron capture effects. High charge states reduce electron stripping, and make bending and acceleration more effective. Electron stripping at higher energies is generally more efficient. Table 2 shows the charge states and energies in the

CERN: The best of the bunch

International Nuclear Information System (INIS)

Gagliardi, F.

1992-01-01

As other factors governing the electron-positron collision rate in CERN's LEP 27-kilometre storage ring reach their limit, one way of coaxing the collision rate higher is to increase the number of bunches stored in the ring

Towards the next chapter

CERN Document Server

2013-01-01

In the late 1970s, while the CERN community was busy preparing the SPS to operate as a collider and planning for LEP, people also had their eyes on the next chapter in the unfolding story of CERN.   That the LEP tunnel should be built with a future hadron collider in mind was a given by the end of the decade. But there had also been proposals to build large proton storage rings, or re-equip the ISR with superconducting magnets. Some people had suggested building an electron-proton collider at CERN, and there were ambitious plans looking far into the future at a possible Very Big Accelerator to be built somewhere in the world, which went by its acronym VBA. For the field of particle physics, with its very long lead times, this is part of the normal cycle, and while most of those options never came to fruition, this process did pave the way for the LHC. Today, with the LHC programme underway, the time has come for CERN to start seriously considering the options for its post-LHC future. Perhaps ...

CERN and the LHC

CERN Multimedia

Cramer, J G

1992-01-01

CERN, a high-energy physics laboratory in Europe, is planning to build a more powerful particle accelerator, the Large Hadronic Collider. The US spreads its accelerators around the country while most of Europe's research is conducted at and around CERN.

The standard model and colliders

International Nuclear Information System (INIS)

Hinchliffe, I.

1987-03-01

Some topics in the standard model of strong and electroweak interactions are discussed, as well as how these topics are relevant for the high energy colliders which will become operational in the next few years. The radiative corrections in the Glashow-Weinberg-Salam model are discussed, stressing how these corrections may be measured at LEP and the SLC. CP violation is discussed briefly, followed by a discussion of the Higgs boson and the searches which are relevant to hadron colliders are then discussed. Some of the problems which the standard model does not solve are discussed, and the energy ranges accessible to the new colliders are indicated

Heavy quark physics in ep collisions at LEP+LHC

International Nuclear Information System (INIS)

Ali, A.; Barreiro, F.; Troconiz, J.F. de; Schuler, G.A.; Bij, J.J. van der

1990-12-01

We study electroweak production of heavy quarks - charm, beauty, and top - in deep inelastic electron-proton collisions at the proposed LEP+LHC collider at CERN. The assumed energy for the collisions is E e =50 GeV, E p =8000 GeV, providing an ep center of mass energy, √s≅1.26 TeV. We invoke the boson-gluon fusion model to estimate theoretical cross sections and distributions for the heavy quarks. Higher order QCD corrections are only approximately taken into account, by assuming a (normalization) K-factor of 2 for the charm and beauty quark production rates and incorporating the parton shower cascades. With these assumptions and the parameterization of Eichten et al. for the structure functions (EHLQ, set 1), we find the following cross sections: σ(ep→c+X)≅O(3 μb), σ(ep→b+X)≅O(40 nb), and σ(ep→t+X)≅4 pb for m t =120 GeV, decreasing to 0.5 pb for m t =250 GeV. These cross sections would provide O(6x10 9 ) charmed hadrons, O(8x10 7 ) beauty hadrons, and O(10 3 ) top hadrons, for an integrated ep luminosity of 1000 pb -1 . The heavy quark rates in ep collisions are considerably smaller than the corresponding rates in pp collisions at LHC, with √s=16 TeV. This gives a clear advantage to pp collisions for top searches. However, for the charmed and beauty quarks only a tiny fraction of the cross sections in p+p→Q+X can be triggered in comparison to the corresponding cross sections in e+p→Q+X, resulting in comparable number of measured heavy quark events in the ep and pp mode. We sketch the energy-momentum profile of heavy quark events in ep collisions and illustrate the kind of analyses that experiments at the LEP+LHC collider would undertake to quantitatively study heavy quark physics. In particular, prospects of measuring the particle-antiparticle mixing parameter x s =ΔM/Γ for the B s 0 -anti B s 0 meson system are evaluated, and search strategies for the top quark in ep collisions are presented. (orig.)

People and things. CERN Courier, Mar 1984, v. 24(2)

International Nuclear Information System (INIS)

Anon.

1984-01-01

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events. Some time ago, Wolfgang ('Pief') Panofsky, Director of SLAC since 1961 and one of the prime movers behind both the famous two-mile electron linac and the Laboratory itself, announced his intention to step down in 1984. Immediately a search began for a worthy successor. Carlo Rubbia, leader of the UA 1 experiment at CERN which last year discovered the W and Z particles, was named by the US science magazine 'Discover' as its 1983 'Scientist of the Year'. A CERN-ECFA Workshop to study the feasibility of hadron colliders which it might at some time in the future be possible to install in the LEP tunnel, is to be held at the University of Lausanne from 21-24 March. Fermilab will host the 1984 US Summer School on High Energy Particle Accelerators from 13-24 August - the fourth in this series of summer schools.The 1984 CERN School of Computing, the eighth in the biennial series, is being organized in collaboration with the Instituto Estudios Energeticos (Junta de Energia Nuclear, Madrid) and the Facultad de Informatica, Barcelona, and will be held from 9-22 September at Aiguablava, Spain. The 1984 Users' Meeting of the High Energy Discussion Group (HEDG) at Brookhaven on 29-31 March will include a Workshop on the possible physics from an improved Alternating Gradient Synchrotron

Observation of Single Isolated Electrons of High Transverse Momentum in Events with Missing Transverse Energy at the CERN pp Collider

DEFF Research Database (Denmark)

Banner, M.; Kofoed-Hansen, O.

1983-01-01

We report the results of a search for single isolated electrons of high transverse momentum at the CERN collider. Above 15 GeV/c, four events are found having large missing transverse energy along a direction opposite in azimuth to that of the high-pT electron. Both the configuration of the events...

Radiological impact of the future CERN program (LEP)

International Nuclear Information System (INIS)

Goebel, K.

1982-01-01

The author discusses the radiation problems which are the radiological influences of LEP which interest the majority of the members of the personnel. The first studies done in this domain are achieved, and the results are published this summer, among others the doses of radiation and of radioactivity and equally the concentration of hoxions gases on the exterior of the enclosure of future installations. The results are the object of discussions and are compared with the norms of radioprotection and with the actual situation in this region. (orig.)

Kurt Hübner, 38 years of service to the accelerator field

CERN Multimedia

2002-01-01

Kurt Hübner will long be remembered at CERN for his leadership in the accelerator field during his 38 years of service to it. A brilliant, conscientious and determined physicist, he has always been known for his humility and humanity. He retired from CERN on 29th November. Kurt Hübner, who is Austrian, joined CERN in 1964 as a fellow, to work on the CESAR electron storage ring project for the ISR. He became a member of the personnel in 1966 and joined the ISR Division two years later. At the end of the 1970s he played an important role in the design studies for LEP, in particular proposing that the existing synchrotrons be used as the injectors for the new collider. It was therefore logical that he should take on the responsibility for designing the LEP injector chain from 1983 onwards. In addition to his involvement in the commissioning and operation of the collider, he took part in drawing up the proposals for the LHC and in the studies for CLIC, the project for a future linear collider...

Future frontiers for e+e- collisions: physics of SLC and LEP

International Nuclear Information System (INIS)

Dorfan, J.M.

1986-04-01

A brief historical review is given of the contribution to particle physics of e + e - interactions, followed by a discussion of the LEP and SLC machines and the reasons for developing linear colliders. A brief overview of the Standard Model and some essential formalism for the process e + e - → f anti f are presented, followed by a discussion of detectors. Tests of the Standard Model and physics beyond the Standard Model that can be made running at the Z 0 are considered. LEP physics at energies above the Z 0 is discussed

First β-beating measurement and optics analysis for the CERN Large Hadron Collider

Directory of Open Access Journals (Sweden)

M. Aiba

2009-08-01

Full Text Available Proton beams were successfully steered through the entire ring of the CERN Large Hadron Collider (LHC on September the 10th of 2008. A reasonable lifetime was achieved for the counterclockwise beam, namely beam 2, after the radiofrequency capture of the particle bunch was established. This provided the unique opportunity of acquiring turn-by-turn betatron oscillations for a maximum of 90 turns right at injection. Transverse coupling was not corrected and chromaticity was estimated to be large. Despite this largely constrained scenario, reliable optics measurements have been accomplished. These measurements together with the application of new algorithms for the reconstruction of optics errors have led to the identification of a dominant error source.

Aleph silicon microstrip vertex detector

CERN Multimedia

Laurent Guiraud

1998-01-01

This microstrip vertex locator was located at the heart of the ALEPH experiment, one of the four experiments at the Large Electron-Positron (LEP) collider. In the experiments at CERN's LEP, which ran from 1989 to 2000, modern silicon microvertex detectors, such as those used at ALEPH, monitored the production of short-lived particles close to the beam pipe.

Report of the 1997 LEP2 working group on 'searches'

International Nuclear Information System (INIS)

Allanach, B.C.; Blair, G.A.; Diaz, M.A.

1997-08-01

A number of research program reports are presented from the LEP2 positron-electron collider in the area of searches for Higgs bosons, supersymmetry and supergravity. Working groups' reports cover prospective sensitivity of Higgs boson searches, radiative corrections to chargino production, charge and colour breaking minima in minimal Supersymmetric Standard Model, R-party violation effects upon unification predictions, searches for new pair-produced particles, single sneutrino production and searches related to effects similar to HERA experiments. The final section of the report summarizes the LEP 2 searches, concentrating on gians from running at 200 GeV and alternative paradigms for supersymmetric phenomenology. (UK)

Simulation of the beam halo from the beam-beam interaction in LEP

International Nuclear Information System (INIS)

Chen, T.; Irwin, J.; Siemann, R.

1994-02-01

The luminosity lifetimes of e + e - colliders are often dominated by the halo produced by the beam-beam interaction. They have developed a simulation technique to model this halo using the flux across boundaries in amplitude space to decrease the CPU time by a factor of one-hundred or more over 'brute force' tracking. It allows simulation of density distributions and halos corresponding to realistic lifetimes. Reference 1 shows the agreement with brute force tracking in a number of cases and the importance of beam-beam resonances in determining the density distribution of large amplitudes. this research is now directed towards comparisons with operating colliders and studies of the combined effects of lattice and beam-beam nonlinearities. LEP offers an ideal opportunity for both, and in this paper they are presenting the first results of LEP simulations

CERN: Important summer for LEAR physics

Energy Technology Data Exchange (ETDEWEB)

Anon.

1990-12-15

An integral part of CERN's comprehensive antiproton facilities is the LEAR low energy antiproton ring which came into action for physics in 1983 and has gone on to host many experiments looking at a wide range of physics topics. With CERN's big SPS proton-antiproton collider now in what could be its final production physics run after an illustrious career which began in 1981, the face of antiproton physics at CERN will change over the next few years. However LEAR runs independently of high energy antiproton operations, and any phasing out of collider operations has no direct impact on LEAR.

The γ*γ* total cross section and the BFKL pomeron at e+e-colliders

International Nuclear Information System (INIS)

Bartels, J.

1996-08-01

We present a numerical estimate of the γ*γ* total cross section at LEP and at the designed e + e - next linear collider (NLC), based upon the BFKL Pomeron. We find for the linear collider that the event rate is substantial provided electrons scattered under small angles can be detected, and a measurement of this cross section provides an excellent test of the BFKL Pomeron. For LEP, although the number of events is substantially smaller, and initial study of this process is feasible. (orig.)

A word from Steve Myers: The Operational Performance Marathon is just starting

CERN Multimedia

2008-01-01

In the previous Bulletin, Lyn (Evans) referred to the construction phase of the LHC as a marathon that is now almost completed. This is absolutely true and thanks to the hard work and dedication of all the construction staff, CERN now has a superb accelerator ready to be operated and driven to its maximum potential performance. However, for many of us, the next phase of operation and exploitation of the LHC is a second marathon and the firing pistol has just been fired. My first encounter with the LHC was in the very early 1980s, when many of us were fully occupied with LEP construction. Through a chance invitation by CERN director Herwig Schopper I participated in a discussion in the US about future proton colliders. Following this meeting, in April 1983, my boss (the late Wolfgang Schnell) and I published "LEP note 440", which gave preliminary estimates of the possible performance of a proton collider in the LEP tunnel. After the controversial de...

Cryogenic testing of by-pass diode stacks for the superconducting magnets of the large hadron collider at CERN

International Nuclear Information System (INIS)

Della Corte, A.; Catitti, A.; Chiarelli, S.; Di Ferdinando, E.; Verdini, L.; Gharib, A.; Hagedorn, D.; Turtu, S.; Basile, G. L.; Taddia, G.; Talli, M.; Viola, R.

2002-01-01

A dedicated facility prepared by ENEA (Italian Agency for Energy and Environment) for the cryogenic testing of by-pass diodes for the protection of the CERN Large Hadron Collider main magnets will be described. This experimental activity is in the frame of a contract awarded to OCEM, an Italian firm active in the field of electronic devices and power supplies, in collaboration with ENEA, for the manufacture and testing of all the diode stacks. In particular, CERN requests the measurement of the reverse and forward voltage diode characteristics at 300 K and 77 K, and endurance test cycles at liquid helium temperature. The experimental set-up at ENEA and data acquisition system developed for the scope will be described and the test results reported

Missing energy at LEP2: W boson and new physics

International Nuclear Information System (INIS)

Zerwas, Dirk

1998-04-01

In 1995 LEP, CERN's large e + e - collider, increased its center-of-mass energy beyond the Z boson resonance up to 184 GeV in 19997. The data recorded by the ALEPH detector allow to study the parameters of the standard model and to search for new particles. The mass of the W boson can be determined at LEP via the measurement of the cross section of W pairs at the production threshold. Two selections for the final states lνlν and τνqq-bar are developed. In combination with the other decay channels, the mass of the W boson and its branching ratios are measured. The reaction e + e - → Weν gives access to the coupling γWW. The cross section of this process is measured and limits on the anomalous couplings (λ γ ,κ γ ) are determined. The non-minimal standard model with an extra scalar doublet predicts the existence of charged Higgs bosons. A selection of the final state τνqq'-bar is developed. In absence of a signal, limits on the mass of the charged Higgs bosons are determined. In a supersymmetric theory each boson is associated to a fermion and vice versa. A search for sleptons, the supersymmetric partners of the leptons, is performed. The result is interpreted in the framework of the minimal supersymmetric extension of the standard model (MSSM). Moreover, in the MSSM a practically invisible W decay is possible. This decay can be detected if the second W decays to standard model particles. A limit on the invisible branching ratio of the W boson is deduced. (author)

Jet physics at LEP

International Nuclear Information System (INIS)

Venus, W.

1991-01-01

The results of studies of the jet structure of hadronic Z 0 decays performed in the first year of Large Electron-Positron collider (LEP) operation are reviewed. The measurements of the quantum chromodynamics (QCD) coupling constant α s (M z )and the detection of the presence of the triple gluon vertex are summarized. After a brief review of the promising status of QCD in relation to even the very soft processes, the running of the coupling constants to high energy is considered in the context of grand unified theories. The necessity and importance of further theoretical work is stressed. (author)

6th IT First Tuesday@CERN

CERN Multimedia

François Grey

2005-01-01

Thursday 12 May, 17:30-19:30, Main Auditorium, CERN Data management in the 21st Century: the Petabyte challenge A Petabyte is a million Gigabytes, the equivalent of over 200,000 DVDs. That may seem like an enormous amount of data, but managing such quantities of data is a reality in the world of science, and is increasingly becoming an imperative in the world of business. This IT First Tuesday@CERN presents the Petabyte challenge, and some of the emerging solutions, from both scientific and commercial perspectives. For CERN's Large Hadron Collider, a Grid solution has been chosen to provide the necessary distributed storage capacity for the anticipated 15 Petabytes of data per year that this collider will produce. IBM is CERN's storage partner in the CERN openlab for DataGrid applications, and is testing the companies innovative TotalStorage SAN distributed filesystem in CERN's demanding IT environment. For Lausanne-based VisioWave, managing stored video data provides an extreme storage challenge. For D...

Preliminary design of CERN Future Circular Collider tunnel: first evaluation of the radiation environment in critical areas for electronics

Science.gov (United States)

Infantino, Angelo; Alía, Rubén García; Besana, Maria Ilaria; Brugger, Markus; Cerutti, Francesco

2017-09-01

As part of its post-LHC high energy physics program, CERN is conducting a study for a new proton-proton collider, called Future Circular Collider (FCC-hh), running at center-of-mass energies of up to 100 TeV in a new 100 km tunnel. The study includes a 90-350 GeV lepton collider (FCC-ee) as well as a lepton-hadron option (FCC-he). In this work, FLUKA Monte Carlo simulation was extensively used to perform a first evaluation of the radiation environment in critical areas for electronics in the FCC-hh tunnel. The model of the tunnel was created based on the original civil engineering studies already performed and further integrated in the existing FLUKA models of the beam line. The radiation levels in critical areas, such as the racks for electronics and cables, power converters, service areas, local tunnel extensions was evaluated.

Preliminary design of CERN Future Circular Collider tunnel: first evaluation of the radiation environment in critical areas for electronics

Directory of Open Access Journals (Sweden)

Infantino Angelo

2017-01-01

Full Text Available As part of its post-LHC high energy physics program, CERN is conducting a study for a new proton-proton collider, called Future Circular Collider (FCC-hh, running at center-of-mass energies of up to 100 TeV in a new 100 km tunnel. The study includes a 90-350 GeV lepton collider (FCC-ee as well as a lepton-hadron option (FCC-he. In this work, FLUKA Monte Carlo simulation was extensively used to perform a first evaluation of the radiation environment in critical areas for electronics in the FCC-hh tunnel. The model of the tunnel was created based on the original civil engineering studies already performed and further integrated in the existing FLUKA models of the beam line. The radiation levels in critical areas, such as the racks for electronics and cables, power converters, service areas, local tunnel extensions was evaluated.

Status of PACMAN Project at CERN

CERN Document Server

Catalan-Lasheras, Nuria; Modena , Michele

2015-01-01

Though the Large Hadron Collider (LHC) at CERN is just at the start of a program expected to run for 20 additional years, CERN is studying the next generation of colliders, like the Compact Linear Collider (CLIC). This project proposes an electron-positron collider with a length close to 50 km and with a centre of mass energy of 3 TeV at the collision point. One of the main challenges is the sub-micrometric size of the beams, down to a few nanometres at the interaction point. As a consequence, the accelerator will require unprecedented nanometric tolerances of beam alignment. A series of several thousands components will have to be assembled, aligned at the micrometre level and most critically, stabilized actively at the nanometre level. PACMAN, a study on Particle Accelerator Components Metrology and Alignment to the Nanometre scale, is a Marie Curie Program supported by the European Commission (FP7 Program), creating a network of 16 Academic and Industrial Partners. The project is hosted at CERN and it offe...

Cryogenic studies for the proposed CERN large hadron electron collider (LHEC)

Science.gov (United States)

Haug, F.; LHeC Study Team, The

2012-06-01

The LHeC (Large Hadron electron Collider) is a proposed future colliding beam facility for lepton-nucleon scattering particle physics at CERN. A new 60 GeV electron accelerator will be added to the existing 27 km circumference 7 TeV LHC for collisions of electrons with protons and heavy ions. Two basic design options are being pursued. The first is a circular accelerator housed in the existing LHC tunnel which is referred to as the "Ring-Ring" version. Low field normal conducting magnets guide the particle beam while superconducting (SC) RF cavities cooled to 2 K are installed at two opposite locations at the LHC tunnel to accelerate the beams. For this version in addition a 10 GeV re-circulating SC injector will be installed. In total four refrigerators with cooling capacities between 1.2 kW and 3 kW @ 4.5 K are needed. The second option, referred to as the "Linac-Ring" version consists of a race-track re-circulating energyrecovery type machine with two 1 km long straight acceleration sections. The 944 high field 2 K SC cavities dissipate 30 kW at CW operation. Eight 10 kW @ 4.5 K refrigerators are proposed. The particle detector contains a combined SC solenoid and dipole forming the cold mass and an independent liquid argon calorimeter. Cooling is done with two individual small sized cryoplants; a 4.5 K helium, and a 87 K liquid nitrogen plant.

The CERN LEP-SPS Librarian system

International Nuclear Information System (INIS)

Corniaux, C.; Morpurgo, G.

1990-01-01

The complexity of a software working environment, such as the control system for the SPS and LEP accelerators, requires a considerable management effort. The software needed to run the machines is continuously evolving, as new releases of application and system programs are introduced rather frequency. Ideally the management effort must coordinate all the different software developers and their users (the machine operating team). A software tool, the Librarian, has been written to help them in performing this task. Its ultimate goal is to enable the accelerator operators to retain control of all the software running in the control system. All the source files needed to produce a piece of running software (a 'product') are saved together, and can be retrieved either individually or as a whole. Management of the different versions of a product is also implemented, as well as a scheme for protections and access rights depending on the type of user (Librarian manager, application manager or software developer). The data base ORACLE has been used to maintain logical links between files saved under the Librarian. (orig.)

CERN: Important summer for LEAR physics

International Nuclear Information System (INIS)

Anon.

1990-01-01

An integral part of CERN's comprehensive antiproton facilities is the LEAR low energy antiproton ring which came into action for physics in 1983 and has gone on to host many experiments looking at a wide range of physics topics. With CERN's big SPS proton-antiproton collider now in what could be its final production physics run after an illustrious career which began in 1981, the face of antiproton physics at CERN will change over the next few years. However LEAR runs independently of high energy antiproton operations, and any phasing out of collider operations has no direct impact on LEAR

FUTURE CIRCULAR COLLIDER LOGISTICS STUDY

CERN Document Server

Beißert, Ulrike; Kuhlmann, Gerd; Nettsträter, Andreas; Prasse, Christian; Wohlfahrt, Andreas

2018-01-01

The Large Hadron Collider (LHC) at the European Organization for Nuclear Research CERN in Geneva is the largest and most powerful collider in the world. CERN and its research and experimental infrastructure is not only a focus for the science community but is also very much in the public eye. With the Future Circular Collider (FCC) Study, CERN has begun to examine the feasibility of a new underground accelerator ring with a length of approximately 100 kilometres. Logistics is of great importance for the construction, assembly and operation of the FCC. During the planning, construction and assembly of the LHC, logistics proved to be one of the key factors. As the FCC is even larger than the LHC, logistics will also become more and more significant. This report therefore shows new concepts, methods and analytics for logistics, supply chain and transport concepts as part of the FCC study. This report deals with three different logistics aspects for the planning and construction phase of FCC: 1. A discussion of d...

Monitoring and control of the muon detector in the L3 experiment at LEP

International Nuclear Information System (INIS)

Gonzalez, E.

1990-01-01

In this report the monitoring system of the muon spectrometer of the L3 detector in LEP at CERN is presented. The system is based on a network of VME's using the OS9 operating system. The design guiding lines and the present system configuration are described both from the hardware and the software point of view. In addition, the report contains the description of the monitored parameters showing typical data collected durintg the first months of LEP operation. (Author)

Proton-antiproton collider physics

CERN Document Server

Altarelli, Guido

1989-01-01

This volume reviews the physics studied at the CERN proton-antiproton collider during its first phase of operation, from the first physics run in 1981 to the last one at the end of 1985. The volume consists of a series of review articles written by physicists who are actively involved with the collider research program. The first article describes the proton-antiproton collider facility itself, including the antiproton source and its principle of operation based on stochastic cooling. The subsequent six articles deal with the various physics subjects studied at the collider. Each article descr

Design of a 120 MeV $H^{-}$ Linac for CERN High-Intensity Applications

CERN Document Server

Gerigk, F

2002-01-01

The SPL (Superconducting Proton Linac) study at CERN foresees the construction of a 2.2 GeV linac as a high beam-power driver for applications such as a second-generation radioactive ion beam facility or a neutrino superbeam. At the same time such a high-performance injector would both modernize and improve the LHC injection chain. The 120 MeV normal-conducting section of the SPL could be used directly in a preliminary stage for H- charge-exchange injection into the PS Booster. This would increase the proton flux to the CERN experiments while also improving the quality and reliability of the beams for the LHC. The 120 MeV linac consists of a front-end, a conventional Drift Tube Linac (DTL) to 40 MeV and a Cell Coupled Drift Tube Linac (CCDTL) to the full energy. All the RF structures will operate at 352 MHz, using klystrons and RF equipment recovered from the LEP collider. This paper concentrates on the design of the 3 to 120 MeV section. It introduces the design criteria for high-stability beam optics and th...

LHC milestone

International Nuclear Information System (INIS)

Anon.

1992-01-01

At the December meeting of CERN's Council, the Organization's Governing Body, the delegates from the 16 Member States unanimously agreed that the LHC proton-proton collider proposed for the 27-kilometre LEP tunnel is the 'right machine for the advance of the subject and of the future of CERN'

Observation of very large transverse momentum jets at the CERN pp collider

CERN Document Server

Banner, M; Bonaudi, Franco; Borer, K; Borghini, M; Chollet, J C; Clark, A G; Conta, C; Darriulat, Pierre; Di Lella, L; Dines-Hansen, J; Dorsaz, P A; Fayard, L; Fraternali, M; Froidevaux, D; Gaillard, J M; Gildemeister, O; Goggi, V G; Grote, H; Hahn, B; Hänni, H; Hansen, J R; Hansen, P; Himel, T; Hungerbühler, V; Jenni, Peter; Kofoed-Hansen, Otto Møgens; Livan, M; Loucatos, Sotirios S; Madsen, B; Mansoulié, B; Mantovani, G C; Mapelli, L; Merkel, B; Mermikides, Michael E; Møllerud, R; Nilsson, B; Onions, Christopher J; Parrour, G; Pastore, F; Plothow-Besch, H; Repellin, J P; Ringel, J; Rothenberg, A F; Roussarie, A; Sauvage, G; Schacher, J; Siegrist, J L; Stocker, F; Teiger, J; Vercesi, V; Williams, H H; Zaccone, Henri; Zeller, W

1982-01-01

The distribution of total transverse energy Sigma E/sub T/ over the pseudorapidity interval -1( eta (1 and an azimuthal range Delta phi =300 degrees has been measured in the UA2 experiment at the CERN pp collider ( \\sqrt{s}=540 GeV) using a highly segmented total absorption calorimeter. In the events with the very large Sigma E/sub T/ ( Sigma E/sub T/>or approximately=60 GeV) most of the transverse energy is found to be contained in small angular regions as expected for high transverse momentum hadron jets. The authors discuss the properties of a sample of two-jet events with invariant two-jet masses up to 140 GeV/c/sup 2/ and measure the cross section for inclusive jet production in the range of jet transverse momenta between 15 and 60 Ge V/c.

CERN'S Fire and Rescue Group Gets New Ambulance

CERN Multimedia

2000-01-01

The ambulance is to replace another based on the off-road vehicle design which was originally acquired for the civil engineering phase of LEP construction. Just one figure, in 1999, the CERN ambulance was called out 195 times.

XUIMS the X-Window User Interface Management System at CERN

CERN Document Server

Van den Eynden, M

1995-01-01

The CERN X-Window User Interface Management System (XUIMS) is a modular and highly configurable software development environment allowing the interactive design, prototyping, and production of OSF/Motif Human Computer Interfaces (HCI). Fully compliant with the X11R5 and OSF/Motif industry standards, XUIMS covers complex software areas like the development of schematics, the visualization and on-line interactions with 2D and 3D scientific data, the display of relational database data, and the direct access to CERN SPS and LEP accelerators equipment. The guarantee of consistency across the applications and the encapsulation of complex functionality in re-usable and user-friendly components has also been implemented through the development of home made graphical objects (widgets) and templates. The XUIMS environment is built with commercial software products integrated in the CERN SPS and LEP controls infrastructure with a very limited home-made effort. Productivity and quality have been improved through less co...

On-Line Radiation Test Facility for Industrial Equipment needed for the Large Hadron Collider at CERN

CERN Document Server

Rausch, R

1999-01-01

The future Large Hadron Collider to be built at CERN will use superconducting magnets cooled down to 1.2 K. To preserve the superconductivity, the energy deposition dose levels in equipment located outside the cryostat, in the LHC tunnel, are calculated to be of the order of 1 to 10 Gy per year. At such dose levels, no major radiation-damage problems are to be expected, and the possibility of installing Commercial Of The Shelf (COTS) electronic equipment in the LHC tunnel along the accelerator is considered. To this purpose, industrial electronic equipment and circuits have to be qualified and tested against radiation to insure their long term stability and reliability. An on-line radiation test facility has been setup at the CERN Super Proton Synchrotron (SPS) and a program of on-line tests for electronic equipment is ongoing. Equipment tested includes Industrial Programmable Logic Controllers (PLCs) from several manufacturers, standard VME modules, Fieldbuses like Profibus, WorldFIP and CAN, various electro...

Development of large-capacity refrigeration at 1.8 K for the Large Hadron Collider at CERN

CERN Document Server

Lebrun, P; Claudet, G

1996-01-01

CERN, the European Laboratory for Particle Physics, is working towards the construction of the Large Hadron Collider (LHC), a high-energy, high-luminosity particle accelerator and collider [1] of 26.7 km circumference, due to start producing frontier physics, by bringing into collision intense proton and ion beams with centre-of-mass energies in the TeV-per-constituent range, at the beginning of the next century. The key technology for achieving this ambitious scientific goal at economically acceptable cost is the use of high-field superconducting magnets using Nb-Ti conductor operating in superfluid helium [2]. To maintain the some 25 km of bending and focusing magnets at their operating temperature of 1.9 K, the LHC cryogenic system will have to produce an unprecedented total refrigeration capacity of about 20 kW at 1.8 K, in eight cryogenic plants distributed around the machine circumference [3]. This has requested the undertaking of an industrial development programme, in the form of a collaboration betwe...

A busy week for Arts@CERN

CERN Multimedia

Antonella Del Rosso

2015-01-01

Last week, Semiconductor – the winners of the Collide@CERN Ars Electronica award for 2015 – and artists Francesco Mariotti and José­-Carlos Mariátegui visited CERN and met the scientists.   Ruth Jarman (left) and Joe Gerhardt (right) of Semiconductor with Peter Jenni, one of the scientists they met during their visit to ATLAS.   Just a few weeks ago, Ruth Jarman and Joe Gerhardt, two English artists collaborating under the name Semiconductor, were awarded the Collide@CERN Ars Electronica prize for 2015. Last week, they came on their first visit to CERN to meet the scientists and select their scientific partner in preparation for their residency. They will soon begin a two-month residency at CERN before going to Linz (Austria), where they will spend a month at the Ars Electronica Futurelab. During their residency, the artists aim to create a digital artwork elaborating on the n...

Production and decay of supersymmetric particles at future colliders

International Nuclear Information System (INIS)

Bartl, A.; Majerotto, W.; Moesslacher, B.

1991-01-01

We describe how supersymmetric particles could be detected at the new colliders HERA, LEP 200, LHC, SSC, and at the possible future linear e + e - collider. We shall present theoretical predictions for production cross sections and decay probabilities, as well as for the important signatures. Our calculations will be based on the Minimal Supersymmetric Standard Model (MSSM) which is the simplest supersymmetric extension of the Standard Model. (authors)

LHC - latest in a long line of rings

Energy Technology Data Exchange (ETDEWEB)

Anon.

1993-12-15

The LHC - Large Hadron Collider - ring in CERN's 27-kilometre LEP tunnel is the natural next link in an accelerator chain first forged in the mid-1950s with the decision to build Europe's first state-of-the-art high energy synchrotron at CERN. A lot of ground has been covered since the LHC idea was launched over a decade ago. While the basic machine design has moved through several iterations, preparations for the experimental programme are well underway. CERN is now responding to the December 1991 request from its governing body, Council, to supply detailed information on the technical feasibility of the machine, its costs, and its experimental programme. In the late 1970s, when plans for CERN's LEP electron-positron collider were being pieced together, far-sighted people were already looking further ahead. With the LEP tunnel itself a major investment for the future, the circumference of the ring and the tunnel cross-section were kept as large as possible, so that another ring could be fitted in when the time came. On the physics front, the ultimate quest was the mysterious higgs mechanism which controls electroweak symmetry breaking. The symmetry of the vacuum is broken by the higgs field. Somewhere along the line, this fundamental field has to show itself as one or more higgs particles.

LHC - latest in a long line of rings

International Nuclear Information System (INIS)

Anon.

1993-01-01

The LHC - Large Hadron Collider - ring in CERN's 27-kilometre LEP tunnel is the natural next link in an accelerator chain first forged in the mid-1950s with the decision to build Europe's first state-of-the-art high energy synchrotron at CERN. A lot of ground has been covered since the LHC idea was launched over a decade ago. While the basic machine design has moved through several iterations, preparations for the experimental programme are well underway. CERN is now responding to the December 1991 request from its governing body, Council, to supply detailed information on the technical feasibility of the machine, its costs, and its experimental programme. In the late 1970s, when plans for CERN's LEP electron-positron collider were being pieced together, far-sighted people were already looking further ahead. With the LEP tunnel itself a major investment for the future, the circumference of the ring and the tunnel cross-section were kept as large as possible, so that another ring could be fitted in when the time came. On the physics front, the ultimate quest was the mysterious higgs mechanism which controls electroweak symmetry breaking. The symmetry of the vacuum is broken by the higgs field. Somewhere along the line, this fundamental field has to show itself as one or more higgs particles

A study of multi-jet events at the CERN anti pp collider and a search for double parton scattering

International Nuclear Information System (INIS)

Alitti, J.; Ambrosini, G.; Ansari, R.; Autiero, D.; Bareyre, P.; Bertram, I.A.; Blaylock, G.; Bonamy, P.; Borer, K.; Bourliaud, M.; Buskulic, D.; Carboni, G.; Cavalli, D.; Cavasinni, V.; Cenci, P.; Chollet, J.C.; Conta, C.; Costa, G.; Costantini, F.; Cozzi, L.; Cravero, A.; Curatolo, M.; Dell'Acqua, A.; DelPrete, T.; DeWolf, R.S.; DiLella, L.; Ducros, Y.; Egan, G.F.; Einsweiler, K.F.; Esposito, B.; Fayard, L.; Federspiel, A.; Ferrari, R.; Fraternali, M.; Froidevaux, D.; Fumagalli, G.; Gaillard, J.M.; Gianotti, F.; Gildemeister, O.; Goessling, C.; Goggi, V.G.; Gruenendahl, S.; Hara, K.; Hellman, S.; Hrivnac, J.; Hufnagel, H.; Hugentobler, E.; Hultqvist, K.; Iacopini, E.; Incandela, J.; Jakobs, K.; Jenni, P.; Kluge, E.E.; Kurz, N.; Lami, S.; Lariccia, P.; Lefebvre, M.; Linssen, L.; Livan, M.; Lubrano, P.; Magneville, C.; Mandelli, L.; Mapelli, L.; Mazzanti, M.; Meier, K.; Merkel, B.; Meyer, J.P.; Moniez, M.; Moning, R.; Morganti, M.; Mueller, L.; Munday, D.J.; Nessi, M.; Nessi-Tedaldi, F.; Onions, C.; Pal, T.; Parker, M.A.; Parrour, G.; Pastore, F.; Pennacchio, E.; Pentney, J.M.; Pepe, M.; Perini, L.; Petridou, C.; Petroff, P.; Plothow-Besch, H.; Polesello, G.; Poppleton, A.; Pretzl, K.; Primavera, M.; Punturo, M.; Repellin, J.P.; Rimoldi, A.; Sacchi, M.; Scampoli, P.; Schacher, J.; Simak, V.; Sing, S.L.; Sondermann, V.; Stapnes, S.; Talamonti, C.; Tondini, F.; Tovey, S.N.; Tsesmelis, E.; Unal, G.; Valdata-Nappi, M.; Vercesi, V.; Weidberg, A.R.; Wells, P.S.; White, T.O.; Wood, D.R.; Wotton, S.A.; Zaccone, H.; Zylberstejn, A.

1991-01-01

A study of events containing at least four high transverse momentum jets and a search for double parton scattering (DPS) have been performed using data collected with the UA2 detector at the CERN anti pp Collider (√s=630 GeV). The results are in good agreement with leading order QCD calculations. A value of σ DPS <0.82 nb at 95% confidence level (CL) is obtained for the DPS cross section. (orig.)

Heavy leptons at hadron colliders

International Nuclear Information System (INIS)

Ohnemus, J.E.

1987-01-01

The recent advent of high energy hadron colliders capable of producing weak bosons has opened new vistas for particle physics research, including the search for a possible fourth generation heavy charged lepton, which is the primary topic of the thesis. Signals for identifying a new heavy lepton have been calculated and compared to Standard Model backgrounds. Results are presented for signals at the CERN collider, the Fermilab collider, and the proposed Superconducting Supercollider

New control architecture for the SPS accelerator at CERN

International Nuclear Information System (INIS)

Kissler, K.H.; Rausch, R.

1992-01-01

The Control System for the 450 Gev proton accelerator SPS at CERN was conceived and implemented some 18 years ago. The 16 Bit minicomputers with their proprietary operating system and interconnection with a dedicated network do not permit the use of modern workstations, international communication standards and industrial software packages. The upgrading of the system has therefore become necessary. After a short review of the history and the current state of the SPS control system, the paper describes how CERN's new control architecture, which will be common to all accelerators, will be realized at the SPS. The migration path ensuring a smooth transition to the final system is outlined. Once the SPS upgrade is complete and following some enhancements to the LEP control system, the operator in the SPS/LEP control center will be working in a single uniform control environment. (author)

Geodesy and metrology of the LEP

International Nuclear Information System (INIS)

Mayoud, M.

1985-01-01

The accurate installation of an accelerator of 8,500 m diameter requires the most refined geodetic techniques. The instrumentation in use incorporates not only lasers and eventually satellites, but also the simple nylon wire. Over 20,000 measurement will be made to install to within 0.1 mm the 5,000 fonctional elements of the LEP machine (Large Electron-Positron Collider). This work will be controlled and checked by portable computers. Each instrument will be automatic and will contain a miniature micro-computer (on a ''flexible-rigid'' card) [fr

The W bosons physics and four-fermion processes in the LEP2 experiments - Monte Carlo approach

International Nuclear Information System (INIS)

Skrzypek, M.

1998-06-01

The computer codes LoralW and YFSWW for Monte Carlo simulation of the four-fermion processes is presented. These programs are dedicated for prediction of W bosons pairs production and theirs decay at LEP experiments at CERN

The collider of the future?

CERN Multimedia

2009-01-01

Why are two studies for one linear collider being conducted in parallel? This is far from a duplication of effort or a waste of resources, since the two studies reflect a complementary strategy aimed at providing the best technology for future physics. On Friday 12 June CERN hosted the first joint meeting between CLIC, ILC and the CERN management.

The LHC Physics Centre at CERN

CERN Multimedia

CERN Bulletin

2010-01-01

Although raw physics data is produced at CERN, thanks to the GRID its analysis is performed in various institutes worldwide. In addition, workshops, conferences and meetings take place all over the world. The physicist community is decentralized, and CERN must continue to provide intellectual leadership. The LHC Physics Centre is the tool that will make this possible.   Until the early days of LEP, a large part of the scientific activity related to CERN’s experiments was strongly centered at the Laboratory. Few places had the infrastructure to host activities such as the working groups preparing the Yellow Reports, and the limited access to information in the pre-web era made CERN the natural place to learn what was happening in the field. “I remember the days when we, the theorists, would come to CERN just to read the most recent preprints, which were reaching CERN's Library before we could get them in our institutes”, says Michelangelo Mangano, a member of the Theo...

Ion Colliders

CERN Document Server

Fischer, W

2014-01-01

High-energy ion colliders are large research tools in nuclear physics to study the Quark-Gluon-Plasma (QGP). The range of collision energy and high luminosity are important design and operational considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species. Ion species range from protons, including polarized protons in RHIC, to heavy nuclei like gold, lead and uranium. Asymmetric collision combinations (e.g. protons against heavy ions) are also essential. For the creation, acceleration, and storage of bright intense ion beams, limits are set by space charge, charge change, and intrabeam scattering effects, as well as beam losses due to a variety of other phenomena. Currently, there are two operating ion colliders, the Relativistic Heavy Ion Collider (RHIC) at BNL, and the Large Hadron Collider (LHC) at CERN.

CERN looks to the long-term future: might a 100km circular collider follow the LHC around mid-century?

CERN Multimedia

CERN. Geneva

2015-01-01

Particle physics is a long-term field of research: the LHC was originally conceived in the 1980s, but did not start running until 25 years later. An accelerator unlike any other, it is now just at the start of a programme that is set to run for another 20 years. While the LHC programme is already well defined for the next two decades, it is now time to look even further ahead, and so CERN is initiating an exploratory study for a future long-term project centred on a next-generation circular collider with a circumference of 80 to 100 kilometres. A worthy successor to the LHC, whose collision energies will reach 13 TeV in 2015, such an accelerator would allow particle physicists to push the boundaries of knowledge even further. The Future Circular Collider (FCC) programme will focus on studies for a hadron collider, like the LHC, capable of reaching unprecedented energies in the region of 100 TeV. It will also study electron-positron and electron-proton options. Opening with an introduction to the LHC and its...

Photoproduction of vector mesons in proton-proton ultraperipheral collisions at the CERN Large Hadron Collider

Science.gov (United States)

Xie, Ya-Ping; Chen, Xurong

2018-05-01

Photoproduction of vector mesons is computed with dipole model in proton-proton ultraperipheral collisions (UPCs) at the CERN Large Hadron Collider (LHC). The dipole model framework is employed in the calculations of vector mesons production in diffractive processes. Parameters of the bCGC model are refitted with the latest inclusive deep inelastic scattering experimental data. Employing the bCGC model and boosted Gaussian light-cone wave function for vector mesons, we obtain the prediction of rapidity distributions of J/ψ and ψ(2s) mesons in proton-proton ultraperipheral collisions at the LHC. The predictions give a good description of the experimental data of LHCb. Predictions of ϕ and ω mesons are also evaluated in this paper.

LEP shines light on dark matter

International Nuclear Information System (INIS)

Fox, Patrick J.; Harnik, Roni; Kopp, Joachim; Tsai, Yuhsin

2011-01-01

Dark matter pair production at high energy colliders may leave observable signatures in the energy and momentum spectra of the objects recoiling against the dark matter. We use LEP data on monophoton events with large missing energy to constrain the coupling of dark matter to electrons. Within a large class of models, our limits are complementary to and competitive with limits on dark matter annihilation and on WIMP-nucleon scattering from indirect and direct searches. Our limits, however, do not suffer from systematic and astrophysical uncertainties associated with direct and indirect limits. For example, we are able to rule out light (< or approx. 10 GeV) thermal relic dark matter with universal couplings exclusively to charged leptons. In addition, for dark matter mass below about 80 GeV, LEP limits are stronger than Fermi constraints on annihilation into charged leptons in dwarf spheroidal galaxies. Within its kinematic reach, LEP also provides the strongest constraints on the spin-dependent direct detection cross section in models with universal couplings to both quarks and leptons. In such models the strongest limit is also set on spin-independent scattering for dark matter masses below ∼4 GeV. Throughout our discussion, we consider both low energy effective theories of dark matter, as well as several motivated renormalizable scenarios involving light mediators.

Le LEP sera encore là en l'an 2000

CERN Multimedia

CERN Press Office. Geneva

1998-01-01

CERN's Large Electron-Positron collider got the green light today to achieve its full potential by running for an additional year in the year 2000. Delegates attending the 110th meeting of the Laboratory's governing body, Council, approved the move after a careful presentation of the proposal's scientific merits and financial aspects by CERN's Director General Chris Llewellyn Smith.

China and CERN renew their Co-operation Agreement

CERN Multimedia

2004-01-01

Dr. Liu Yanhua, Chinese Vice Minister of Science and Technology, and Dr. Robert Aymar, Director-General of CERN, sign a new Co-operation Agreement between the Government of the People's Republic of China and CERN. During his visit to CERN on 17 February, Liu Yanhua, Vice Minister of Science and Technology of the People's Republic of China, signed a new Co-operation Agreement with the Laboratory. The Agreement, which is valid for a period of five years and renewable, lays down the framework for the development of scientific and technological co-operation between CERN and China. This includes China's participation, as a non-Member State, in CERN's research projects as well as its main programmes. Robert Aymar and Liu Yanhua underlined that this Agreement will provide an excellent framework for close co-operation on the LHC Programme and Grid and accelerator technologies. Scientific co-operation between China and CERN is nothing new, as Chinese physicists already took part in the LEP experiments. Today, CERN's C...

Polarisation and precise calibration of the LEP beam energy

CERN Document Server

Koutchouk, Jean-Pierre

2002-01-01

We report in this article on two issues of precision accelerator physics, performed at the LEP collider, that challenged international collaborations. The first result is an increase of the polarisation degree from an almost vanishing natural level to 50%, opening the way to energy calibration by resonant depolarisation. The second result is a systematic and precise determination of the collider centre-of- mass energy correcting for subtle effects such as the azimuthal variation of the beam energy, the magnet temperature, the effects of parasitic earth currents and terrestrial tides. It resulted in an extremely accurate test of the standard model and set significant constraints on the top quark and Higgs masses. (16 refs).

The future of the Large Hadron Collider and CERN.

Science.gov (United States)

Heuer, Rolf-Dieter

2012-02-28

This paper presents the Large Hadron Collider (LHC) and its current scientific programme and outlines options for high-energy colliders at the energy frontier for the years to come. The immediate plans include the exploitation of the LHC at its design luminosity and energy, as well as upgrades to the LHC and its injectors. This may be followed by a linear electron-positron collider, based on the technology being developed by the Compact Linear Collider and the International Linear Collider collaborations, or by a high-energy electron-proton machine. This contribution describes the past, present and future directions, all of which have a unique value to add to experimental particle physics, and concludes by outlining key messages for the way forward.

Prospects for next-generation e+e- linear colliders

International Nuclear Information System (INIS)

Ruth, R.D.

1990-02-01

The purpose of this paper is to review progress in the US towards a next generation linear collider. During 1988, there were three workshops held on linear colliders: ''Physics of Linear Colliders,'' in Capri, Italy, June 14--18, 1988; Snowmass 88 (Linear Collider subsection) June 27--July 15, 1988; and SLAC International Workshop on Next Generation Linear Colliders, November 28--December 9, 1988. In this paper, I focus on reviewing the issues and progress on a next generation linear collider. The energy range is dictated by physics with a mass reach well beyond LEP, although somewhat short of SSC. The luminosity is that required to obtain 10 3 --10 4 units of R 0 per year. The length is consistent with a site on Stanford land with collision occurring on the SLAC site; the power was determined by economic considerations. Finally, the technology as limited by the desire to have a next generation linear collider by the next century. 37 refs., 3 figs., 6 tabs

People and things. CERN Courier, Apr-May 1995, v. 35(3)

Energy Technology Data Exchange (ETDEWEB)

Anon.

1995-04-15

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events: Spokesmen at the CDF experiment at Fermilab's tevatron protonantiproton collider serve two-year terms. Most recently Mel Shochet (Chicago) and Bill Carithers ( LBL ) were co-spokesmen. Before the recent round of elections, Mel declared that he did not want to run again, having served for six and a half years (following the departure of Roy Schwitters to the SSC). Bill Carithers (who replaced Alvin Tollestrup two years ago) did decide to run again. Through a complicated process, a long list of nominees was narrowed to six candidates and an election held via the World Wide Web. Results were announced on January 19: Bill Carithers was reelected for another term, and Giorgio Bellettini (Pisa) becomes his new cospokesman. (see Top discovery' - page 1). Career milestone - Lucien Montanet: Officially 'retiring' from CERN is Lucien Montanet, whose impressive career spans a wide range of physics interests and is characterized by his ebullient enthusiasm. Joining CERN in 1957 for cosmic ray experiments, he went on to participate in pioneer CERN investigations using bubble chambers and using antiprotons, going on in the 1960s to play a prominent role in the discovery and investigation of hadron resonances, and becoming a key figure in the international Particle Data Group. His objective review talks on the complex hadron resonance scene became a feature at international meetings. In the 1970s he pushed the development of the European Hybrid Spectrometer project and went on to join the L3 and Crystal Barrel collaborations at LEP and LEAR respectively. As well as experimental physics, he has also contributed to theoretical work (with Francis Low) and phenomenology (with Leon van Hove). In 1985 he became the CERN-Russia coordinator, a demanding responsibility now inherited by Jim Allaby as coordinator

People and things. CERN Courier, Apr-May 1995, v. 35(3)

International Nuclear Information System (INIS)

Anon.

1995-01-01

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events: Spokesmen at the CDF experiment at Fermilab's tevatron protonantiproton collider serve two-year terms. Most recently Mel Shochet (Chicago) and Bill Carithers ( LBL ) were co-spokesmen. Before the recent round of elections, Mel declared that he did not want to run again, having served for six and a half years (following the departure of Roy Schwitters to the SSC). Bill Carithers (who replaced Alvin Tollestrup two years ago) did decide to run again. Through a complicated process, a long list of nominees was narrowed to six candidates and an election held via the World Wide Web. Results were announced on January 19: Bill Carithers was reelected for another term, and Giorgio Bellettini (Pisa) becomes his new cospokesman. (see Top discovery' - page 1). Career milestone - Lucien Montanet: Officially 'retiring' from CERN is Lucien Montanet, whose impressive career spans a wide range of physics interests and is characterized by his ebullient enthusiasm. Joining CERN in 1957 for cosmic ray experiments, he went on to participate in pioneer CERN investigations using bubble chambers and using antiprotons, going on in the 1960s to play a prominent role in the discovery and investigation of hadron resonances, and becoming a key figure in the international Particle Data Group. His objective review talks on the complex hadron resonance scene became a feature at international meetings. In the 1970s he pushed the development of the European Hybrid Spectrometer project and went on to join the L3 and Crystal Barrel collaborations at LEP and LEAR respectively. As well as experimental physics, he has also contributed to theoretical work (with Francis Low) and phenomenology (with Leon van Hove). In 1985 he became the CERN-Russia coordinator, a demanding responsibility now inherited by Jim

Microscopic examination and elemental analysis of surface defects in LEP superconducting cavities

International Nuclear Information System (INIS)

Benvenuti, C.; Cosso, R.; Hauer, M.; Hellgren, N.; Lacarrere, D.

1996-01-01

A diagnostic tool, based on a computer controlled surface analysis instrument, incorporating secondary electron imaging, static auger electron spectroscopy and scanning auger mapping has been designed and built at CERN to characterize the inner surface of LEP superconducting cavities with provide unsatisfactory radio-frequency performance. The experimental results obtained to date are reported and discussed. (author)

Britain's delegation to CERN, the European Centre for Nuclear Research near Geneva, voted in favour of a project which take seven years to build, involve a 27 kilometre long tunnel, and cost 230 million pounds. Now LEP receives the go-ahead later this month

CERN Multimedia

Llewellyn Smith, Christopher Hubert

1981-01-01

Britain's delegation to CERN, the European Centre for Nuclear Research near Geneva, voted in favour of a project which take seven years to build, involve a 27 kilometre long tunnel, and cost 230 million pounds. Now LEP receives the go-ahead later this month

Environmental radiation monitoring on the CERN sites during 1995

International Nuclear Information System (INIS)

Moritz, L.; Wittekind, D.

1996-01-01

The CERN environmental monitoring programme covers the Meyrin and Prevessin sites, the six isolated islands (BA1, BA2, BA3, BA4, BA5, BA6) along the SPS Main Ring, the neutrino cave (BA7), and the seven surface areas PA2-PA8 specific to LEP. The results of the routine environmental monitoring programme enable CERN's compliance with national regulations of the host states and CERN's own Radiation Protection Policy to be assessed. Part I of this Annual Report describes the results of measurements which are relevant for assessing the radiological impact of CERN operations on the environment and the population living in the vicinity of the CERN sites. Measurements of radioactivity released into the atmosphere and into water, as well as measurements of stray radiation at or near the CERN site boundaries are reported

Search for R-parity violating decays of supersymmetric particles in final states with jets and leptons using the OPAL detector at LEP

CERN Document Server

Mutter, Andreas

2004-01-01

Of all the data of the years 1998 to 2000 taken with the OPAL detector at the e+e-- collider LEP at CERN, final states with jets and leptons have been analysed. A search for decays of new particles postulated by supersymmetric extensions of the standard model of particle physics has been performed. Only decays violating the quantum number R-parity (Rp) that is introduced in supersymmetric models have been investigated. The violation of Rp leads to experimental signatures that are in general completely different from those in the Rp conserving case. If Rp is violated, processes that lead to a rapid decay of the proton might be possible. In order to avoid such processes, in most investigations Rp is assumed to be conserved. However, there is no theoretically compelling reason for this assumption. Therefore, the possibility of R-parity violation should also be considered.

GUT feeling

Energy Technology Data Exchange (ETDEWEB)

Anon.

1991-09-15

CERN's LEP electron-positron collider is going full blast, with each of the four big experiments - Aleph, Delphi, L3 and Opal - now able to see thousands of Z particles (the electrically neutral carrier of the weak nuclear force) in a day.

The CLIC stability study on the feasibility of colliding high energy nanobeams

CERN Document Server

Assmann, R W; Guignard, Gilbert; Leros, Nicolas; Redaelli, S; Schulte, Daniel; Wilson, Ian H; Zimmermann, Frank

2002-01-01

The Compact Linear Collider (CLIC) study at CERN proposes a linear collider with nanometer-size colliding beams at an energy of 3 TeV c.m. ("colliding high energy nanobeams"). The transport, demagnification and collision of these nanobeams imposes magnet vibration tolerances that range from 0.2 nm to a few nanometers. This is well below the floor vibration usually observed. A test stand for magnet stability was set-up at CERN in the immediate neighborhood of roads, operating accelerators, workshops, and regular office space. It was equipped with modern stabilization equipment. The experimental setup and first preliminary results are presented. (10 refs).

Emilio Picasso (1927-2014)

CERN Multimedia

2014-01-01

Many people in the high-energy physics community will be deeply saddened to learn that Emilio Picasso passed away on Sunday 12 October after a long illness. His name is closely linked in particular with the construction of CERN’s Large Electron-Positron (LEP) collider.   Emilio studied physics at the University of Genoa. He came to CERN in 1964 as a research associate to work on the ‘g-2’ experiments, which he was to lead when he became a staff member in 1966. These experiments spanned two decades at two different muon storage rings and became famous for their precision studies of the muon and tests of quantum electrodynamics. In 1979, Emilio became responsible for the coordination of work by several institutes, including CERN, on the design and construction of superconducting RF cavities for LEP. Then, in 1981, the Director-General, Herwig Schopper, appointed him as a CERN director and LEP project leader. Emilio immediately set up a management board of the best exp...

People and things. CERN Courier, Sep 1995, v. 35(6)

International Nuclear Information System (INIS)

Anon.

1995-01-01

institute atZeuthen, Berlin, and Gunter Wolf is formerly spokesman of the ZEUS experiment at DESY's HERA electron-proton collider. He is also Chairman of CERN's Scientific Policy Committee. Sau Lan Wu is a member of the Aleph collaboration at CERN's LEP electronpositron collider. Their work, which was done in 1979 when all four were members of the TASSO collaboration, demonstrated that the gluons of the strong interactions were a physical reality. The existence of such three-jet events in electron-positron collisions had been predicted in a pioneer CERN Theory Division paper by John Ellis, Mary K. Gaillard and Graham Ross. There has always been keen rivalry between the four 1979 PETRA collaborations - JADE, MARK-J, PLUTO and TASSO. In recognition of this, and in an unprecedented move, the EPS Executive Committee has awarded a special complementary prize to the four collaborations 'for establishing the existence of the gluon in independent and simultaneous ways'. Also playing major roles in the 1979 accomplishments were Herwig Schopper, Chairman of the DESY Board of Directors at the time, and PETRA project leader Gustav-Adolf Voss, who ensured that such an excellent machine was built on schedule and within the allocated budget

People and things. CERN Courier, Sep 1995, v. 35(6)

Energy Technology Data Exchange (ETDEWEB)

Anon.

1995-09-15

Gunter Wolf is formerly spokesman of the ZEUS experiment at DESY's HERA electron-proton collider. He is also Chairman of CERN's Scientific Policy Committee. Sau Lan Wu is a member of the Aleph collaboration at CERN's LEP electronpositron collider. Their work, which was done in 1979 when all four were members of the TASSO collaboration, demonstrated that the gluons of the strong interactions were a physical reality. The existence of such three-jet events in electron-positron collisions had been predicted in a pioneer CERN Theory Division paper by John Ellis, Mary K. Gaillard and Graham Ross. There has always been keen rivalry between the four 1979 PETRA collaborations - JADE, MARK-J, PLUTO and TASSO. In recognition of this, and in an unprecedented move, the EPS Executive Committee has awarded a special complementary prize to the four collaborations 'for establishing the existence of the gluon in independent and simultaneous ways'. Also playing major roles in the 1979 accomplishments were Herwig Schopper, Chairman of the DESY Board of Directors at the time, and PETRA project leader Gustav-Adolf Voss, who ensured that such an excellent machine was built on schedule and within the allocated budget.

The LEP 2 machine : pushing to the limits 209 GeV! Exhibition LEPFest 2000

CERN Multimedia

2000-01-01

By installing 288 new superconducting accelerating cavities after 1995,and thanks to the excellent work of the CERN teams,energies up to 209 GeV -well beyond LEP 's original design energy -have been achieved.Significant experi- mental data have been collected at energies in excess of 206 GeV.

Preparation of niobium coated copper superconducting rf cavities for the large electron positron collider

International Nuclear Information System (INIS)

Benvenuti, C.; Bloess, D.; Chiaveri, E.; Hilleret, N.; Minestrini, M.; Weingarten, W.

1988-01-01

Since 1980 development work has been carried out at CERN aiming at producing niobium coated superconducting RF cavities in the framework of the foreseen LEP energy upgrading above the initial 55 GeV. During 1987 a 4-cell LEP cavity without coupling ports has been successfully coated for the first time. Meanwhile, cathodes for coating the coupling ports were built and tested. The effort has been subsequently directed to preparing at least one (possibly 2) coated cavity(ies) to be installed in LEP during 1989. In this paper the various production steps of these cavities are reconsidered in view of industrial production

CERN: LHC magnets

Energy Technology Data Exchange (ETDEWEB)

Anon.

1992-08-15

With test magnets for CERN's LHC proton-proton collider regularly attaining field strengths which show that 10 Tesla is not forbidden territory, attention turns to why and where quenches happen. If 'training' can be reduced, superconducting magnets become easier to commission.

Experiments at CERN in 1984

International Nuclear Information System (INIS)

1984-11-01

This book is a compilation of the current experimental program at CERN. The experiments listed are being performed at one of the following machines: the Super Proton Synchrotron (SPS), the Proton Synchrotron (PS) and the Synchro-Cyclotron (SC). The Intersecting Storage Rings (ISR) have ceased functioning early this year. The four approved experiments to be done by means of the Large Electron Positron machine (LEP) are also listed. (orig./HSI)

The small angle tile calorimeter in the DELPHI experiment

International Nuclear Information System (INIS)

Alvsvaag, S.J.; Bari, M.; Barreira, G.; Benvenuti, A.C.; Bigi, M.; Bonesini, M.; Bozzo, M.; Camporesi, T.; Carling, H.; Cassio, V.; Castellani, L.; Cereseto, R.; Chignoli, F.; Della Ricca, G.; Dharmasiri, D.R.; Santo, M.C. Espirito; Falk, E.; Fenyuk, A.; Ferrari, P.; Gamba, D.; Giordano, V.; Gouz, Yu.; Guerzoni, M.; Gumenyuk, S.; Hedberg, V.; Jarlskog, G.; Karyukhin, A.; Klovning, A.; Konoplyannikov, A.; Kronkvist, I.; Lanceri, L.; Leoni, R.; Maeland, O.A.; Maio, A.; Mazza, R.; Migliore, E.; Navarria, F.L.; Negri, P.; Nossum, B.; Obraztsov, V.; Onofre, A.; Paganoni, M.; Pegoraro, M.; Peralta, L.; Petrovykh, L.; Pimenta, M.; Poropat, P.; Prest, M.; Read, A.L.; Romero, A.; Shalanda, N.; Simonetti, L.; Skaali, T.B.; Stugu, B.; Terranova, F.; Tome, B.; Torassa, E.; Trapani, P.P.; Verardi, M.G.; Vallazza, E.; Vlasov, E.; Zaitsev, A.

1999-01-01

The Small angle TIle Calorimeter (STIC) provides calorimetric coverage in the very forward region of the DELPHI experiment at the CERN LEP collider. The structure of the calorimeters, built with a so-called 'shashlik' technique, gives a perfectly hermetic calorimeter and still allows for the insertion of tracking detectors within the sampling structure to measure the direction of the showering particle. A charged-particle veto system, composed of two scintillator layers, makes it possible to trigger on single photon events and provides e-γ separation. Results are presented from the extensive studies of these detectors in the CERN testbeams prior of installation and of the detector performance at LEP

People and things. CERN Courier, Dec 1987, v. 27(10)

International Nuclear Information System (INIS)

Anon.

1987-01-01

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events:; The third symposium 'Astronomy, Cosmology and Fundamental Physics' organized by CERN and ESO (European Southern Observatory) will be held in Bologna, Italy, from 16-18 May on the special occasion of the ninth centenary of the University of Bologna. At CERN, a prototype superconducting accelerating cavity of the type envisaged for LEP beams has been installed for tests in the SPS ring, where it helped take an electron beam to 18 GeV

People and things. CERN Courier, Dec 1987, v. 27(10)

Energy Technology Data Exchange (ETDEWEB)

Anon.

1987-12-15

The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events:; The third symposium 'Astronomy, Cosmology and Fundamental Physics' organized by CERN and ESO (European Southern Observatory) will be held in Bologna, Italy, from 16-18 May on the special occasion of the ninth centenary of the University of Bologna. At CERN, a prototype superconducting accelerating cavity of the type envisaged for LEP beams has been installed for tests in the SPS ring, where it helped take an electron beam to 18 GeV.

Who cares about particle physics? making sense of the Higgs boson, the Large Hadron Collider and CERN

CERN Document Server

AUTHOR|(CDS)2051327

2016-01-01

CERN, the European Laboratory for particle physics, regularly makes the news. What kind of research happens at this international laboratory and how does it impact people's daily lives? Why is the discovery of the Higgs boson so important? Particle physics describes all matter found on Earth, in stars and all galaxies but it also tries to go beyond what is known to describe dark matter, a form of matter five times more prevalent than the known, regular matter. How do we know this mysterious dark matter exists and is there a chance it will be discovered soon? About sixty countries contributed to the construction of the gigantic Large Hadron Collider (LHC) at CERN and its immense detectors. Dive in to discover how international teams of researchers work together to push scientific knowledge forward. Here is a book written for every person who wishes to learn a little more about particle physics, without requiring prior scientific knowledge. It starts from the basics to build a solid understanding of current res...

CERN's vacuums honoured to the full

CERN Multimedia

2002-01-01

CERN's Cristoforo Benvenuti is awarded one of the most prestigious prizes in the world of vacuum techniques     Because we constantly run into such individuals, we tend to forget that CERN has specialists with world reputations. It takes the international prizes they win to remind us of the fact. One such prize, the American Vacuum Society (AVS)'s Gaede-Langmuir Award for 2002, has gone to Cristoforo Benvenuti, Leader of the Surfaces and Materials Technologies Group in EST Division. The award, conferred once every two years, is one of the leading prizes in the vacuum field. By coincidence, its very first winner was Pierre Auger, one of CERN's founding fathers, back in 1978. Cristoforo Benvenuti, a senior physicist who joined CERN in 1966, has been singled out for his work on getter technologies. These technologies made their name at CERN with the coming of LEP, where they were used for pumping the machine. Getter is a material with the property of capturing gas molecules and thereby actin...

Collider physics for the late 1980's

International Nuclear Information System (INIS)

Hinchliffe, I.

1987-01-01

Topics in the Standard Model of strong and electroweak interactions and how these topics are relevant for the high energy colliders are discussed. Radiative corrections in the Glashow-Weinberg-Salam model are discussed, stressing how these corrections may be measured at LEP and the SLC. CP violation is discussed, followed by a discussion of the Higgs boson and the searches which can be carried out for it. Some features of quantum chromodynamics are discussed which are relevant to hadron colliders. Some of the problems which the Standard Model does not solve are discussed. 115 refs., 53 figs

Measurement of muon pair production around the Z-resonance using the L3 detector at LEP

International Nuclear Information System (INIS)

Timmermans, C.W.J.P.

1992-01-01

The Z and W ± bosons, both detected at CERN in 1983, are among the most important particles in the standard model of electro-weak interactions. Together with the massles γ, these heavy bosons are the carriers of the so-called electro-weak force. The LEP (Large Electron Positron) collider provides the opportunity of a precise measurement of the properties of the Z-boson. Its mass M Z and width Γ Z are key-parameters in the standard model. In spite of the relatively small partial width Γ μ for Z -> μ + μ - , the reaction e + e - >μ + μ - (γ) is the cleanest channel to test the standard model. The measurements of the lineshape and forward-backward asymmetry of this reaction belong to the best methods to determine g V and g A , the neutral current vector and axial vector coupling constants. Accurate measurements of M Z , Γ Z , Γ μ , g V and g A provide a stringent test of consistencies and predictions of the standard model. The measurements presented here are performed with the L 3 detector, one of the four detectors at the LEP-ring. In this thesis, first a number of aspects of the standard model are discussed. This is followed by a description of the L 3 detector, in particular the muon detector. After that the measurements are presented. Finally, the measured lineshape and asymmetry are interpreted in terms of standard model variables, and compared to standard model predictions. (author). 62 refs., 50 figs., 22 tabs

GUT feeling

International Nuclear Information System (INIS)

Anon.

1991-01-01

CERN's LEP electron-positron collider is going full blast, with each of the four big experiments - Aleph, Delphi, L3 and Opal - now able to see thousands of Z particles (the electrically neutral carrier of the weak nuclear force) in a day

CERN and the high energy frontier

Directory of Open Access Journals (Sweden)

Tsesmelis Emmanuel

2014-04-01

Full Text Available This paper presents the particle physics programme at CERN at the high-energy frontier. Starting from the key open questions in particle physics and the large-scale science facilities existing at CERN, concentrating on the Large Hadron Collider(LHC, this paper goes on to present future possibilities for global projects in high energy physics. The paper presents options for future colliders, all being within the framework of the recently updated European Strategy for Particle Physics, and all of which have a unique value to add to experimental particle physics. The paper concludes by outlining key messages for the way forward for high-energy physics research.

The vacuum chamber in the interaction region of particle colliders a historical study and developments implementations in the LHCb experiment at CERN

CERN Document Server

Knaster, J R; Gamez-Mejias, L

2004-01-01

The history of particle colliders begins in the early 60's when an idea previously patented by R. Wideroe in 1953 is constructed. The design of the vacuum chamber in their experimental area became essential as it was the rst physical barrier that the particles to be detected needed to traverse. The interaction of the products of the collisions with the vacuum chamber structural materials, hindered the identification of the significative events. This Thesis analyses the historical evolution of the experimental vacuum chambers and summarizes the technical criteria that are to be fulfilled. The Large Hadron Collider (LHC) presently under construction at CERN is the last generation of particle colliders. Four big experiments will be in operation (ATLAS, CMS, ALICE and LHCb) in the LHC with diferent physics objectives. In particular, LHCb will be devoted to the study of CP violation and the design of its vacuum chamber is the scope of this Thesis. Physics simulations with an initial design consisting of a conical ...

Large Hadron Collider

CERN Multimedia

2007-01-01

"In the spring 2008, the Large Hadron Collider (LHC) machine at CERN (the European Particle Physics laboratory) will be switched on for the first time. The huge machine is housed in a circular tunnel, 27 km long, excavated deep under the French-Swiss border near Geneva." (1,5 page)

Jonathan Sladen (1957-2009)

CERN Multimedia

2009-01-01

We deeply regret to announce the death of Mr Jonathan Sladen on 19 May 2009. Mr Sladen, who was born on 9 February 1957, was a member of the BE Department and had worked at CERN since 1985. The Director-General has sent his family a message of condolence on behalf of the CERN personnel. Social Affairs Human Resources Department Jonathan made outstanding contributions to the success of the LEP collider. The fast timing system he developed for synchronizing the LEP RF system performed unfailingly and with excellent precision throughout the lifetime of the accelerator. He was a highly motivated member of the LEP RF team, participating enthusiastically in the huge task of maintaining the RF system in a state of peak operational availability for physics. He contributed to many important performance enhancements which allowed LEP to reach such high energies. Later in his career Jonathan took responsibility for the low level RF system of the CLIC Test Facility. Here he...

CERN: LHC magnets

International Nuclear Information System (INIS)

Anon.

1992-01-01

With test magnets for CERN's LHC proton-proton collider regularly attaining field strengths which show that 10 Tesla is not forbidden territory, attention turns to why and where quenches happen. If 'training' can be reduced, superconducting magnets become easier to commission

Destination Universe: The Incredible Journey of a Proton in the Large Hadron Collider

CERN Multimedia

Lefevre, C

2008-01-01

This brochure illustrates the incredible journey of a proton as he winds his way through the CERN accelerator chain and ends up inside the Large Hadron Collider (LHC). The LHC is CERN's flagship particle accelerator which can collide protons together at close to the speed of light, creating circumstances like those just seconds after the Big Bang.

CLIC: developing a linear collider

CERN Multimedia

Laurent Guiraud

1999-01-01

Compact Linear Collider (CLIC) is a CERN project to provide high-energy electron-positron collisions. Instead of conventional radio-frequency klystrons, CLIC will use a low-energy, high-intensity primary beam to produce acceleration.

Physics at LEP2. Vol. 2

International Nuclear Information System (INIS)

Altarelli, G.; Sjoestrand, T.; Zwirner, F.

1995-01-01

This is final report of the Workshop on Physics at LEP2, held at CERN during 1995. The first part of vol. 1 is devoted to aspects of machine physics of particular relevance to experiments, including the energy, luminosity and interaction regions, as well as the measurement of beam energy. The second part of vol. 1 is a relatively concise, but fairly complete, handbook on the physics of e + e - annihilation above the WW threshold and up to √s∼200 GeV. It contains discussions on WW cross-sections and distributions, W mass determination, Standard Model processes, QCD and gamma-gamma physics, as well as aspects of discovery physics, such as Higgs, new particle searches, triple gauge boson couplings and Z'. The second volume contains a review of the existing Monte Carlo generators for LEP2 physics. These include generators for WW physics, QCD and gamma-gamma processes, Bhabha scattering and discovery physics. A special effort was made to co-ordinate the different parts, with a view to achieving a systematic and balanced review of the subject, rather than just publishing a collection of separate contributions. (orig.)

Physics at LEP2. Vol. 1

International Nuclear Information System (INIS)

Altarelli, G.; Sjoestrand, T.; Zwirner, F.

1996-01-01

This is the final report of the Workshop on Physics at LEP2, held at CERN during 1995. The first part of vol. 1 is devoted to aspects of machine physics of particular relevance to experiments, including the energy, luminosity and interaction regions, as well as the measurement of beam energy. The second part of vol. 1 is a relatively concise, but fairly complete, handbook on the physics of e + e - annihilation above the WW threshold and up to √s∼200 GeV. It contains discussions on WW cross-sections and distributions, W mass determination, Standard Model processes, QCD and gamma-gamma physics, as well as aspects of discovery physics, such as Higgs, new particle searches, triple gauge boson couplings and Z'. The second volume contains a review of the existing Monte Carlo generators for LEP2 physics. These include generators for WW physics, QCD and gamma-gamma processes, Bhabha scattering and discovery physics. A special effort was made to co-ordinate the different parts, with a view to achieving a systematic and balanced review of the subject, rather than just publishing a collection of separate contributions. (orig.)

Physics at LEP2. Vol. 2

Energy Technology Data Exchange (ETDEWEB)

Altarelli, G [ed.; Sjoestrand, T [ed.; Zwirner, F [ed.

1995-02-19

This is final report of the Workshop on Physics at LEP2, held at CERN during 1995. The first part of vol. 1 is devoted to aspects of machine physics of particular relevance to experiments, including the energy, luminosity and interaction regions, as well as the measurement of beam energy. The second part of vol. 1 is a relatively concise, but fairly complete, handbook on the physics of e{sup +}e{sup -} annihilation above the WW threshold and up to {radical}s{approx}200 GeV. It contains discussions on WW cross-sections and distributions, W mass determination, Standard Model processes, QCD and gamma-gamma physics, as well as aspects of discovery physics, such as Higgs, new particle searches, triple gauge boson couplings and Z`. The second volume contains a review of the existing Monte Carlo generators for LEP2 physics. These include generators for WW physics, QCD and gamma-gamma processes, Bhabha scattering and discovery physics. A special effort was made to co-ordinate the different parts, with a view to achieving a systematic and balanced review of the subject, rather than just publishing a collection of separate contributions. (orig.).

Learning with the ATLAS Experiment at CERN

Science.gov (United States)

Barnett, R. M.; Johansson, K. E.; Kourkoumelis, C.; Long, L.; Pequenao, J.; Reimers, C.; Watkins, P.

2012-01-01

With the start of the LHC, the new particle collider at CERN, the ATLAS experiment is also providing high-energy particle collisions for educational purposes. Several education projects--education scenarios--have been developed and tested on students and teachers in several European countries within the Learning with ATLAS@CERN project. These…

CDD CERN Drawings Directory User's manual Version 1.1

CERN Document Server

Delamare, Christophe; Jeannin, F; Petit, S

1996-01-01

CDD (CERN Drawings Directory) is a multi-platform utility which manages engineering drawings made in any division at CERN. The aim of CDD is not to store the graphical drawing itself, but to store a reference with some information related to the drawing. Access to this data is provided via a graphical user interface which is based upon ORACLE Forms and via WWW. Drawings following different numbering systems and different management rules can be handled by CDD. The only condition is that those particular functionalities are well defined. Several drawing systems have been identified in CERN and therefore considered when designing the application. The current version of CDD focuses on systems EST, LEP, ST-IE, SPS, ST-CE and the experiments ALICE, ATLAS, CMS and LHCb. Other CERN systems could be easily integrated upon demand.

End-view of the DELPHI detector

CERN Multimedia

1996-01-01

End-view of the 10-m diameter DELPHI detector at CERN's LEP electron-positron collider from 1989 to 2000. Its concentric modules, including a pioneer large-scale application of the Ring Imaging Cherenkov technique to differentiate between all the various secondary particles, ensure high precision and 'granularity'.

Higgs hints

Energy Technology Data Exchange (ETDEWEB)

Anon.

1991-10-15

As well as dominating the news at the recent Joint International Lepton-Photon Symposium and Europhysics Conference on High Energy Physics in Geneva, results from the four big experiments - Aleph , Delphi, L3 and Opal - at CERN's big LEP electron-positron collider had far-reaching implications.

ECFA workshop on LEP 200. Vol. 1 and 2

International Nuclear Information System (INIS)

Boehm, A.; Hoogland, W.

1987-01-01

On the initiative of the European Committee for Future Accelerators, a workshop was organized to study experimental and theoretical aspects of the physics feasible at LEP with the beam energy increased to its design value of 100 GeV per beam. These two volumes provide the written versions of the reports presented by nine working groups to the workshop, as well as the presentations on the machine upgrade itself and the potential of hadron colliders and of HERA for LEP 200 physics. Each working group studied a specific topic, evaluating in some detail the requirements both for the detectors and for the machine of W mass measurements, W decay properties, W production dynamics, electroweak radiative corrections, two-photon physics, new heavy quarks and leptons, Higgs particles, supersymmetric particles, and composite models. The proceedings also include some of the more detailed work done in the framework of the working groups. (orig.)

High energy accelerator and colliding beam user group

International Nuclear Information System (INIS)

1990-09-01

This report discusses the following topics: OPAL experiment at LEP; Dφ experiment at Fermilab; deep inelastic muon interactions at TEV II; CYGNUS experiment; final results from ν e -e elastic scattering; physics with CLEO detector at CESR; results from JADE at PETRA; rare kaon-decay experiment at BNL; search for top quark; and super conducting super collider activities

Operational Performance and Improvements to the RF Power Sources for the Compact Linear Collider Test Facility (CTF3) at CERN

OpenAIRE

McMonagle, Gerard

2006-01-01

The CERN CTF3 facility is being used to test and demonstrate key technical issues for the CLIC (Compact Linear Collider) study. Pulsed RF power sources are essential elements in this test facility. Klystrons at S-band (29998.55 GHz), in conjunction with pulse compression systems, are used to power the Drive Beam Accelerator (DBA) to achieve an electron beam energy of 150 MeV. The L-Band RF system, includes broadband Travelling Wave Tubes (TWTs) for beam bunching with 'phase coded' sub pulses ...

LEP physics

CERN Multimedia

CERN. Geneva

2001-01-01

Various aspects of the physics made at LEP 1 and LEP 2 (precision measurements and searches for new physics will be discussed, from the fundamental motivations to the publication of the results. The techniques and tools developed and applied to reach the a priori goals of LEP (beam energy measurement, luminosity determination, event selection,...) will be described with a few meaningful examples. The high level techniques & bright ideas which allowed LEP to exceed by a large amount its design performance, and the consequences outcome will also be presented.

Superplasticiteit bij Cern

NARCIS (Netherlands)

Snippe, Q.H.C.; Snippe, Corijn

2008-01-01

Op CERN, het Europees onderzoekscentrum voor subatomaire fysica in Genève, wordt dit jaar een nieuwe deeltjesversneller, de Large Hadron Collider (LHC), in werking gesteld die nieuwe inzichten moet bieden over hoe de kleinste deeltjes der materie zich gedragen. Om hierachter te komen, is op plaatsen

Academic Training Lecture - 2009-2010

CERN Multimedia

HR Department

2010-01-01

Regular Programme 15, 16, 17 & 18 February 2010 from 11:00 to 12:00 - Main Auditorium, Bldg. 500   Monday 15 February Physics Requirements and Experimental Conditions (1/4) by Dr. Marco Battaglia (CERN-PH/University of California, Santa Cruz, USA) How is the anticipated physics program of a future e+e- collider shaping the R&D for new detectors in collider particle physics ? This presentation will review the main physics requirements and experimental conditions comparing to LHC and LEP. In particular, I shall discuss how e+e- experimentation is expected to change moving from LEP-2 up to multi-TeV energies. Tuesday 16 February Tracking and Vertexing (2/4) by Dr. Marco Battaglia (CERN-PH/University of California, Santa Cruz, USA) Efficient and precise determination of the flavour of partons in multi-hadron final states is essential to the anticipated LC physics program. This makes tracking in the vicinity of the interaction region of great importance. Tracking extrapolation and mo...

Transmission Line Analysis of the Superconducting Quadrupole Chains of the LHC Collider at CERN

CERN Document Server

Dahlerup-Petersen, K

2003-01-01

Key information for determination of fundamental design features of magnet powering and protection circuits can be retrieved from the results of transmission line calculations of the superconducting magnet chains in a particle accelerator. Modelling and simulation of the behaviour of long magnet strings provide important data for the expected electrical behaviour and performances under all operating conditions. The presented results of a transmission line study concerns the sixteen superconducting main quadrupole chains QF/QD of CERN's future LHC collider. The paper details the elaboration of the synthesized electrical model of the individual quadrupoles and the associated lumped transmission line. It presents results on the current ripple for a given converter voltage output characteristics, the magnet excitation, leakage and earth currents during the ramping procedure, the impedance resonance spectrum and the need for individual magnet damping and the propagation, reflection, superposition and damping of th...

Progress on next generation linear colliders

International Nuclear Information System (INIS)

Ruth, R.D.

1989-01-01

In this paper, I focus on reviewing the issues and progress on a next generation linear collider with the general parameters of energy, luminosity, length, power, technology. The energy range is dictated by physics with a mass reach well beyond LEP, although somewhat short of SSC. The luminosity is that required to obtain 10 3 /minus/ 10 4 units of R 0 per year. The length is consistent with a site on Stanford land with collisions occurring on the SLAC site. The power was determined by economic considerations. Finally, the technology was limited by the desire to have a next generation linear collider before the next century. 25 refs., 3 figs., 6 tabs

The large electron positron collider (LEP) for particle physics

International Nuclear Information System (INIS)

Landshoff, P.

1981-01-01

The 12 member states of the European high energy physics laboratory CERN are considering the construction of a huge new accelerator. This article outlines present understanding of the fundamental forces of nature and the subnuclear structure of matter, and describes the accelerator that will enable some of their mysteries to be explained. (author)

The CERN linear collider test facility (CTF)

International Nuclear Information System (INIS)

Baconnier, Y.; Battisti, S.; Bossart, R.; Delahaye, J.P.; Geissler, K.K.; Godot, J.C.; Huebner, K.; Madsen, J.H.B.; Potier, J.P.; Riche, A.J.; Sladen, J.; Suberlucq, G.; Wilson, I.; Wuensch, W.

1992-01-01

The CTF (Collider Test Facility) was brought into service last year. The 3 GHz gun produced a beam of 3 MeV/c which was accelerated to 40 MeV/c. This beam, passing a prototype CLIC (linear collider) structure, generated a sizeable amount of 30 GHz power. This paper describes the results and experience with the gun driven by a 8 ns long laser pulse and its CsI photo cathode, the beam behaviour, the beam diagnostics in particular with the bunch measurements by Cerenkov or transition radiation light and streak camera, the photo cathode research, and the beam dynamics studies on space charge effects. (Author)4 figs., tab., 6 refs

The promise of the large collider

CERN Multimedia

2007-01-01

"In 2007, the most powerful particle accelerator ever built, CERN's new Large hadron Collider, will probe the secrets of matter in the energy states prevailing in the moments after the Big Bang. By colliding particles together when they are moving at close to the speed of ight, physicists hope to find out about matter in its earliest forms, using the energy produced by the collisions." (2 pages)

The large electron positron collider (LEP) for particle physics

CERN Document Server

Landshoff, Peter V

1981-01-01

The 12 member states of the European high energy physics laboratory CERN are considering the construction of a huge new accelerator. The author outlines the understanding of the fundamental forces of nature and the subnuclear structure of matter, and describes the accelerator that will enable some of their mysteries to be explained. (6 refs).

The small angle tile calorimeter in the DELPHI experiment

CERN Document Server

Alvsvaag, S J; Barreira, G; Benvenuti, Alberto C; Bigi, M; Bonesini, M; Bozzo, M; Camporesi, T; Carling, H; Cassio, V; Castellani, L; Cereseto, R; Chignoli, F; Della Ricca, G; Dharmasiri, D R; Espirito-Santo, M C; Falk, E; Fenyuk, A; Ferrari, P; Gamba, D; Giordano, V; Guz, Yu; Guerzoni, M; Gumenyuk, S A; Hedberg, V; Jarlskog, G; Karyukhin, A N; Klovning, A; Konoplyannikov, A K; Kronkvist, I J; Lanceri, L; Leoni, R; Maeland, O A; Maio, A; Mazza, R; Migliore, E; Navarria, Francesco Luigi; Negri, P; Nossum, B; Obraztsov, V F; Onofre, A; Paganoni, M; Pegoraro, M; Peralta, L; Petrovykh, L P; Pimenta, M; Poropat, P; Prest, M; Read, A L; Romero, A; Shalanda, N A; Simonetti, L; Skaali, T B; Stugu, B; Terranova, F; Tomé, B; Torassa, E; Trapani, P P; Verardi, M G; Vallazza, E; Vlasov, E; Zaitsev, A

1999-01-01

The {\\bf S}mall angle {\\bf TI}le {\\bf C}alorimeter ({\\bf STIC}) provides calorimetric coverage in the very forward region of the DELPHI experiment at the CERN LEP collider. The structure of the calorimeters, built with a so-called ``shashlik'' technique, gives a perfectly hermetic calorimeter and still allows for the insertion of tracking detectors within the sampling structure to measure the direction of the showering particle. A charged-particle veto system, composed of two scintillator layers, makes it possible to trigger on single photon events and provides e-$\\gamma$ separat ion. Results are presented from the extensive studies of these detectors in the CERN testbeams prior to installation and of the detector performance at LEP.

CERN, accelerator of motivation

CERN Multimedia

François Becler

2014-01-01

Have your dreams ever come true? My dream did, when I was lucky enough to be allowed into the world’s largest particle physics laboratory and spend five whole days there.   François, in front of LEP's DELPHI detector, displayed in the LHCb cavern. François was given the opportunity to visit the experiment during his placement at CERN. I’m a pupil in my last year at the Collège Jean-Jacques Rousseau in Saint-Julien-en-Genevois and was on a work experience placement at CERN from 16 to 20 December last year. I’m so happy I was chosen because working alongside physicists and engineers of all nationalities was like a dream come true. The first thing that impressed me was the size of the site, its infrastructures and facilities but also the fact that I was working in a prestigious, world-renowned organisation. I spent lots of time looking at the map and trying to find my way around... CERN's such a massive place ! Th...

Singapore's double festival

Energy Technology Data Exchange (ETDEWEB)

Fraser, Gordon

1990-09-15

Coinciding with celebrations for the nation's 25th anniversary, the 25th International Conference on High Energy Physics, held in Singapore from 2-8 August, was itself a double festival, with the Standard Model of contemporary physics and CERN's new LEP electron-positron collider providing the twin themes.

Le Japon contribue au grand collisionneur de hadrons du CERN

CERN Multimedia

CERN Press Office. Geneva

1995-01-01

Japan's Ministry of Education, Science and Culture (Monbusho), announced on May 10 that it would help to finance the construction of CERN*'s next particle accelerator, the Large Hadron Collider (LHC). This announcement follows the visit of a CERN delegation, led by Director-General Prof. Christopher Llewellyn Smith to Japan in March 1995.

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

Aleph

Energy Technology Data Exchange (ETDEWEB)

Anon.

1991-01-15

This is the second in a series of articles on the four experiments at CERN's LEP electron-positron collider. Although only having completed several data-taking runs, these mighty collaborations have over ten years of history behind them. They involve over 2,000 physicists from CERN's Member States, plus Brazil, Bulgaria, Canada, China, Czechoslovakia, Finland, Hungary, India, Israel, Japan, Poland, the USA, the USSR, and the Joint Institute for Nuclear Research, Dubna.

The proton-antiproton collider

International Nuclear Information System (INIS)

Evans, L.

1988-01-01

The subject of this lecture is the CERN Proton-Antiproton (panti p) Collider, in which John Adams was intimately involved at the design, development, and construction stages. Its history is traced from the original proposal in 1966, to the first panti p collisions in the Super Proton Synchrotron (SPS) in 1981, and to the present time with drastically improved performance. This project led to the discovery of the intermediate vector boson in 1983 and produced one of the most exciting and productive physics periods in CERN's history. (orig.)

High energy accelerator and colliding beam user group

Energy Technology Data Exchange (ETDEWEB)

1990-09-01

This report discusses the following topics: OPAL experiment at LEP; D{phi} experiment at Fermilab; deep inelastic muon interactions at TEV II; CYGNUS experiment; final results from {nu}{sub e}{sup {minus}e} elastic scattering; physics with CLEO detector at CESR; results from JADE at PETRA; rare kaon-decay experiment at BNL; search for top quark; and super conducting super collider activities.

Towards Future Circular Colliders

CERN Document Server

AUTHOR|(CDS)2108454; Zimmermann, Frank

2016-01-01

The Large Hadron Collider (LHC) at CERN presently provides proton-proton collisions at a centre-of-mass (c.m.) energy of 13 TeV. The LHC design was started more than 30 years ago, and its physics programme will extend through the second half of the 2030’s. The global Future Circular Collider (FCC) study is now preparing for a post-LHC project. The FCC study focuses on the design of a 100-TeV hadron collider (FCC-hh) in a new ∼100 km tunnel. It also includes the design of a high-luminosity electron-positron collider (FCC-ee) as a potential intermediate step, and a lepton-hadron collider option (FCC-he). The scope of the FCC study comprises accelerators, technology, infrastructure, detectors, physics, concepts for worldwide data services, international governance models, and implementation scenarios. Among the FCC core technologies figure 16-T dipole magnets, based on $Nb_3Sn$ superconductor, for the FCC-hh hadron collider, and a highly efficient superconducting radiofrequency system for the FCC-ee lepton c...

The Thermosiphon Cooling System of the ATLAS Experiment at the CERN Large Hadron Collider

CERN Document Server

Battistin, M; Bitadze, A; Bonneau, P; Botelho-Direito, J; Boyd, G; Corbaz, F; Crespo-Lopez, O; Da Riva, E; Degeorge, C; Deterre, C; DiGirolamo, B; Doubek, M; Favre, G; Godlewski, J; Hallewell, G; Katunin, S; Lefils, D; Lombard, D; McMahon, S; Nagai, K; Robinson, D; Rossi, C; Rozanov, A; Vacek, V; Zwalinski, L

2015-01-01

The silicon tracker of the ATLAS experiment at CERN Large Hadron Collider will operate around –15°C to minimize the effects of radiation damage. The present cooling system is based on a conventional evaporative circuit, removing around 60 kW of heat dissipated by the silicon sensors and their local electronics. The compressors in the present circuit have proved less reliable than originally hoped, and will be replaced with a thermosiphon. The working principle of the thermosiphon uses gravity to circulate the coolant without any mechanical components (compressors or pumps) in the primary coolant circuit. The fluorocarbon coolant will be condensed at a temperature and pressure lower than those in the on-detector evaporators, but at a higher altitude, taking advantage of the 92 m height difference between the underground experiment and the services located on the surface. An extensive campaign of tests, detailed in this paper, was performed using two small-scale thermosiphon systems. These tests confirmed th...

CASE in CERN's accelerator sector

International Nuclear Information System (INIS)

Albrecht, A.; Cabas-Alonso, A.; Chevrier, F.

1992-01-01

As in the software industry where computer aided software engineering (CASE) methodologies and tools are commonly used, CERN endeavours to introduce this technology to improve the efficiency of designing, producing and maintaining software. A large project is currently under development in the administrative area whereas a dedicated group had been set up to evaluate state of the art techniques for software development relating to physics experiments. A similar activity, though on a smaller scale, has been initiated in the accelerator sector also in view of the large amount of software that will be required by the LEP200 and the LHC projects. This paper briefly describes this technology and gives an account of current experience with the use of CASE methods and tools for technical projects in the accelerator sector at CERN. (author)

Performance of the DELPHI detector

CERN Document Server

Abreu, P; Adye, T; Agasi, E; Ajinenko, I; Aleksan, Roy; Alekseev, G D; Alemany, R; Allport, P P; Almehed, S; Alvsvaag, S J; Amaldi, Ugo; Amato, S; Andreazza, A; Andrieux, M L; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barate, R; Barbiellini, Guido; Bardin, Dimitri Yuri; Baroncelli, A; Bärring, O; Barrio, J A; Bartl, Walter; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Benvenuti, Alberto C; Berggren, M; Bertrand, D; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bloch, D; Blume, M; Blyth, S; Bolognese, T; Bonesini, M; Bonivento, W; Booth, P S L; Borisov, G; Bosio, C; Bosworth, S; Botner, O; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenke, T; Brenner, R A; Bricman, C; Brillault, L; Brown, R C A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschmann, P; Buys, A; Cabrera, S; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Cankocak, K; Cao, F; Carena, F; Carrilho, P; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Cerrito, L; Chabaud, V; Charpentier, P; Chaussard, L; Chauveau, J; Checchia, P; Chelkov, G A; Chen, M; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Cindro, V; Collins, P; Contreras, J L; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Dahl-Jensen, Erik; Dahm, J; D'Almagne, B; Dam, M; Damgaard, G; Dauncey, P D; Davenport, Martyn; Da Silva, W; Defoix, C; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Brabandere, S; De Clercq, C; La Vaissière, C de; De Lotto, B; De Min, A; De Paula, L S; De Saint-Jean, C; Dijkstra, H; Di Ciaccio, Lucia; Djama, F; Dolbeau, J; Dönszelmann, M; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Dufour, Y; Dupont, F; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Ershaidat, N; Erzen, B; Espirito-Santo, M C; Falaleev, V P; Falk, E; Fassouliotis, D; Feindt, Michael; Fenyuk, A; Ferrer, A; Filippas-Tassos, A; Firestone, A; Fischer, P A; Föth, H; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frenkiel, P; Fries, D E C; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Gerdyukov, L N; Gibbs, M; Gokieli, R; Golob, B; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Graziani, E; Grosdidier, G; Grzelak, K; Gumenyuk, S A; Gunnarsson, P; Günther, M; Guy, J; Hahn, F; Hahn, S; Hajduk, Z; Hallgren, A; Hamacher, K; Hao, W; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Higón, E; Hilke, Hans Jürgen; Hill, T S; Holmgren, S O; Holt, P J; Holthuizen, D J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, L B; Jönsson, P E; Joram, Christian; Juillot, P; Kaiser, M; Kapusta, F; Karafasoulis, K; Karlsson, M; Karvelas, E; Karyukhin, A N; Katsanevas, S; Katsoufis, E C; Keränen, R; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klein, H; Klovning, A; Kluit, P M; Köne, B; Kokkinias, P; Koratzinos, M; Kourkoumelis, C; Kuznetsov, O; Kramer, P H; Krammer, Manfred; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Kubinec, P; Kucewicz, W; Kurvinen, K L; Lacasta, C; Laktineh, I; Lamblot, S; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Lapin, V; Last, I; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leitner, R; Lemoigne, Y; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Liko, D; Lindner, R; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; López, J M; López-Aguera, M A; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Maehlum, G; Maio, A; Malychev, V; Mandl, F; Marco, J; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Maron, T; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Masik, J; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; Medbo, J; Meroni, C; Meyer, S; Meyer, W T; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Møller, R; Mönig, K; Monge, M R; Morettini, P; Müller, H; Mundim, L M; Murray, J; Muryn, B; Myatt, Gerald; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nieuwenhuizen, M; Nikolaenko, V; Niss, P; Nomerotski, A; Normand, Ainsley; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Österberg, K; Ouraou, A; Paganini, P; Paganoni, M; Pagès, P; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Passeri, A; Pegoraro, M; Peralta, L; Perevozchikov, V; Pernegger, H; Perrotta, A; Petridou, C; Petrolini, A; Petrovykh, M; Phillips, H T; Piana, G; Pierre, F; Pimenta, M; Pindo, M; Plaszczynski, S; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Prest, M; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rames, J; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Renton, P B; Resvanis, L K; Richard, F; Richardson, J; Rídky, J; Rinaudo, G; Ripp, I; Romero, A; Roncagliolo, I; Ronchese, P; Roos, L; Rosenberg, E I; Rosso, E; Roudeau, Patrick; Rovelli, T; Rückstuhl, W; Ruhlmann-Kleider, V; Ruiz, A; Rybicki, K; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sánchez, J; Sannino, M; Schimmelpfennig, M; Schneider, H; Schwickerath, U; Schyns, M A E; Sciolla, G; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Shellard, R C; Siccama, I; Siegrist, P; Simonetti, S; Simonetto, F; Sissakian, A N; Sitár, B; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Solovyanov, O; Sosnowski, R; Souza-Santos, D; Spiriti, E; Sponholz, P; Squarcia, S; Stanescu, C; Stapnes, Steinar; Stavitski, I; Stichelbaut, F; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tavernet, J P; Chikilev, O G; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Toet, D Z; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Trischuk, W; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tyndel, M; Tzamarias, S; Überschär, B; Ullaland, O; Valenti, G; Vallazza, E; Van der Velde, C; van Apeldoorn, G W; van Dam, P; Van Doninck, W K; Van Eldik, J; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vlasov, E; Vodopyanov, A S; Vrba, V; Wahlen, H; Walck, C; Weierstall, M; Weilhammer, Peter; Weiser, C; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Witek, M; Woschnagg, K; Yip, K; Zach, F; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zito, M; Zontar, D; Zuberi, R; Zucchelli, G C; Zumerle, G; Belokopytov, Yu; Charpentier, Ph; Gavillet, Ph; Gouz, Yu; Jarlskog, Ch

1996-01-01

DELPHI (DEtector with Lepton, Photon and Hadron Identification) is a detector for e^+e^- physics, designed to provide high granularity over a 4\\pi solid angle, allowing an effective particle identification. It has been operating at the LEP (Large Electron-Positron) collider at CERN since 1989. This article reviews its performance.

Destination Universe: The Incredible Journey of a Proton in the Large Hadron Collider (English version)

CERN Multimedia

Lefevre, C

2008-01-01

This brochure illustrates the incredible journey of a proton as he winds his way through the CERN accelerator chain and ends up inside the Large Hadron Collider (LHC). The LHC is CERN's flagship particle accelerator which can collide protons together at close to the speed of light, creating circumstances like those just seconds after the Big Bang.

Calculations of safe collimator settings and β^{*} at the CERN Large Hadron Collider

Directory of Open Access Journals (Sweden)

R. Bruce

2015-06-01

Full Text Available The first run of the Large Hadron Collider (LHC at CERN was very successful and resulted in important physics discoveries. One way of increasing the luminosity in a collider, which gave a very significant contribution to the LHC performance in the first run and can be used even if the beam intensity cannot be increased, is to decrease the transverse beam size at the interaction points by reducing the optical function β^{*}. However, when doing so, the beam becomes larger in the final focusing system, which could expose its aperture to beam losses. For the LHC, which is designed to store beams with a total energy of 362 MJ, this is critical, since the loss of even a small fraction of the beam could cause a magnet quench or even damage. Therefore, the machine aperture has to be protected by the collimation system. The settings of the collimators constrain the maximum beam size that can be tolerated and therefore impose a lower limit on β^{*}. In this paper, we present calculations to determine safe collimator settings and the resulting limit on β^{*}, based on available aperture and operational stability of the machine. Our model was used to determine the LHC configurations in 2011 and 2012 and it was found that β^{*} could be decreased significantly compared to the conservative model used in 2010. The gain in luminosity resulting from the decreased margins between collimators was more than a factor 2, and a further contribution from the use of realistic aperture estimates based on measurements was almost as large. This has played an essential role in the rapid and successful accumulation of experimental data in the LHC.

Calculations of safe collimator settings and β* at the CERN Large Hadron Collider

Science.gov (United States)

Bruce, R.; Assmann, R. W.; Redaelli, S.

2015-06-01

The first run of the Large Hadron Collider (LHC) at CERN was very successful and resulted in important physics discoveries. One way of increasing the luminosity in a collider, which gave a very significant contribution to the LHC performance in the first run and can be used even if the beam intensity cannot be increased, is to decrease the transverse beam size at the interaction points by reducing the optical function β*. However, when doing so, the beam becomes larger in the final focusing system, which could expose its aperture to beam losses. For the LHC, which is designed to store beams with a total energy of 362 MJ, this is critical, since the loss of even a small fraction of the beam could cause a magnet quench or even damage. Therefore, the machine aperture has to be protected by the collimation system. The settings of the collimators constrain the maximum beam size that can be tolerated and therefore impose a lower limit on β*. In this paper, we present calculations to determine safe collimator settings and the resulting limit on β*, based on available aperture and operational stability of the machine. Our model was used to determine the LHC configurations in 2011 and 2012 and it was found that β* could be decreased significantly compared to the conservative model used in 2010. The gain in luminosity resulting from the decreased margins between collimators was more than a factor 2, and a further contribution from the use of realistic aperture estimates based on measurements was almost as large. This has played an essential role in the rapid and successful accumulation of experimental data in the LHC.

CERN agonizes over whether to keep up the hunt for the Higgs

CERN Multimedia

2000-01-01

Senior managers at CERN were meeting as Nature went to press, to decide whether to fund a one-year extension for LEP, at an estimated cost of 100 million CHF, in a bid to confirm possible earlier sightings of the Higgs boson (3 paragraphs).

Towards TeV-scale electron-positron collisions: the Compact Linear Collider (CLIC)

Science.gov (United States)

Doebert, Steffen; Sicking, Eva

2018-02-01

The Compact Linear Collider (CLIC), a future electron-positron collider at the energy frontier, has the potential to change our understanding of the universe. Proposed to follow the Large Hardron Collider (LHC) programme at CERN, it is conceived for precision measurements as well as for searches for new phenomena.

Collider physics: A theorist's view

International Nuclear Information System (INIS)

Ellis, S.D.

1986-06-01

Recent experimental results from the CERN anti p p Collider are reviewed from a theorist's perspective. The conclusion is that the standard model is impressively verified and nothing else seems to be present. Some other relevant phenomenological and theoretical issues are also reviewed

Signatures of massive sgoldstinos at e+e- colliders

International Nuclear Information System (INIS)

Perazzi, Elena; Ridolfi, Giovanni; Zwirner, Fabio

2000-01-01

In supersymmetric extensions of the Standard Model with a very light gravitino, the effective theory at the weak scale should contain not only the goldstino G-tilde, but also its supersymmetric partners, the sgoldstinos. In the simplest case, the goldstino is a gauge-singlet and its superpartners are two neutral spin-0 particles, S and P. We study possible signals of massive sgoldstinos at e + e - colliders, focusing on those that are most relevant at LEP energies. We show that the LEP constraints on e + e - →γS (γP), ZS (ZP) or e + e - S (e + e - P), followed by S(P) decaying into two gluon jets, can lead to stringent combined bounds on the gravitino and sgoldstino masses

Le Japon devient observateur au CERN

CERN Multimedia

CERN Press Office. Geneva

1995-01-01

A Japanese delegation, lead by Mr. Kaoru Yosano, Japan's Minister of Monbusho, (Ministry of Education, Science and Culture), was warmly applauded by the delegates of CERN's Member States when it entered the Council Chamber for the first time as an official Observer. Mr. Yosano, thanked the CERN Council for unanimously agreeing to grant Japan Official Observer Status and also accepting Japan's offer to contribute to the Large Hadron Collider (LHC) project.

CERN boss quashes LHC delay rumours

CERN Multimedia

2007-01-01

"Robert Aymar, the director general of CERN, has dispelled rumours that a series of buckled electrical connectors at the Large Hadron Collider will delay the accelerator's official start-up date of May 2008. Writing in this week's CERN Bulletin, Aymar says that the problem concerns only a small percentage of the connectors and that it is "business as usual" for bringing the new accelerator online." (1,5 page)

Proposal for the award of an industrial support contract for radiation monitoring services for LEP dismantling

CERN Document Server

2000-01-01

This document concerns the award of an Industrial Service contract for radiation monitoring services for LEP dismantling. Following a market survey carried out among 34 firms in nine Member States, a call for tenders (IT-2769/SL/LEP) was sent on 13 March 2000 to seven firms and three consortia in five Member States. By the closing date, CERN had received six tenders from three firms and three consortia in four Member States. The Finance Committee is invited to agree to the negotiation of a contract with the consortium ISS MULTISERVICE (CH), NFI (SE) and ISS GEBÄUDESERVICE (DE), the lowest technically qualified bidder, for radiation monitoring services for LEP dismantling for a total amount of 990 792 Swiss francs, not subject to revision. The firm has indicated the following distribution by country of the contract value covered by this adjudication proposal: CH-59%, DE-26%, SE-15%.

1994 expected to be year of decision for European Super Collider.

CERN Multimedia

Sweet, William N

1994-01-01

Plans to build Europe's counterpart to the US' Superconducting Super Collider, the Large Hadron Collider, may push through when the CERN Council meets on Apr 15, 1994. The European scientific community is optimistic that the plan will be approved.

Deformation analysis of LEP

International Nuclear Information System (INIS)

Jin, F.; Mayoud, M.; Quesnel, J.P.

1999-01-01

LEP (Large Electron Positron Collider) is in an underground accelerator, located in a tunnel of 27 km circumference and from 40 to 160 m deep. It is the largest accelerator in the world. The electrons and positrons circulate in opposite directions and hit each other in four points. The collisions are observed by means of detectors, housed in large underground caverns. Due to the sensitivity of such accelerators to alignment errors a complete leveling is made every year, followed by a 'smoothing' process - i.e. an optimal refinement of successive positions - which makes that the accelerator is kept operational with respect to misalignments. The annual leveling of LEP can be characterised as follows: - A quasi circle of 27 km circumference in tunnel; - Measurements with a LEICA NA3000 (σ = ± 0.4 mm/km, statistically ± 0.04 to ± 0.05 mm/station, at intervals of 39.5 m); - Maximum height difference of 120 m between the highest point and the lowest point; - Measured points: alignment reference targets of the quadrupole magnets (entrance and exit points); -800 quadrupole magnets, 1600 points to measure; - Cholesky method, with two independent traverses (forward/backward loops). The data processing is made by least squares, according to a free network concept. In addition, a smoothing procedure (successive fits within a sliding window) is also carried out after each annual leveling measurement, in the purpose of refining the successive positions and finding the points being vertically too far (more than 0.3 mm in general) from the local smoothing curve. These points are then brought physically on their smoothed position (realignment) in order to keep the vertical configuration of LEP as optimal as possible. Tilt (transverse slope) measurements are also taken during this realignment process, thus putting the corrected element back to its right transverse position and reducing the correlated radial movement associated to this defect. (authors)

Singapore's double festival

International Nuclear Information System (INIS)

Fraser, Gordon

1990-01-01

Coinciding with celebrations for the nation's 25th anniversary, the 25th International Conference on High Energy Physics, held in Singapore from 2-8 August, was itself a double festival, with the Standard Model of contemporary physics and CERN's new LEP electron-positron collider providing the twin themes

Big research in new dimensions. Thinkers of our time about the actual elementary-particle physics at CERN; Grossforschung in neuen Dimensionen. Denker unserer Zeit ueber die aktuelle Elementarteilchenphysik am CERN

Energy Technology Data Exchange (ETDEWEB)

Kommer, Christoph (ed.) [Heidelberg Univ. (Germany); DKFZ, Heidelberg (Germany); Satz, Helmut [Bielefeld Univ. (Germany). Fakultaet fuer Physik; Blanchard, Philippe [Bielefeld Univ. (Germany). Abt. Theoretische Physik

2016-07-01

The following topics are dealt with: Research from the highest energies to the smallest particles at CERN, the laborious way to the Large Hadronic Collider, CERN as accelerator of techniques, culture, and society, a philosophical and sociological perspective of questions concerning CERN, quark matter research at CERN, the FAIR facility for antiproton and ion research. (HSI)

The software for the CERN LEP beam orbit measurement system

International Nuclear Information System (INIS)

Morpurgo, G.

1992-01-01

The Beam Orbit Measurement (BOM) system of LEP consists of 504 pickups, distributed all around the accelerator, that are capable of measuring the positions of the two beams. Their activity has to be synchronized, and the data produced by them have to be collected together, for example to form a 'closed orbit measurement' or a 'trajectory measurement'. On the user side, several clients can access simultaneously the results from this instrument. An automatic acquisition mode, and an 'on request' one, can run in parallel. This results in a very flexible and powerful system. The functionality of the BOM system is fully described, as well as the structure of the software processes which constitute the system, and their interconnections. Problems solved during the implementation are emphasized. (author)

Timeline for Particle Collider in doubt

CERN Multimedia

Klapper, Bradley S

2007-01-01

"Officials at CERN said the possible delays in getting the particle collider back online are the result of the magnet failure and cooling processes that have been slower than expected for the 17-mile tunnel." (1,5 page)

HALO | Arts at CERN

CERN Multimedia

Caraban Gonzalez, Noemi

2018-01-01

In 2015, the artists participated in a research residency at CERN and began to work with data captured by ATLAS, one of the four detectors at the Large Hadron Collider (LHC) that sits in a cavern 100 metres below ground near the main site of CERN, in Meyrin (Switzerland). For Art Basel, they created HALO, an installation that surrounds visitors with data collected by the ATLAS experiment at the LHC. HALO consists of a 10 m wide cylinder defined by vertical piano wires, within which a 4-m tall screen displays particle collisions. The data also triggers hammers that strike the vertical wires and set up vibrations to create a truly multisensory experience. More info: https://arts.cern/event/unveiling-halo-art-basel

Brief history for the search and discovery of the Higgs particle - A personal perspective

CERN Document Server

Wu, Sau Lan

2014-01-01

In 1964, a new particle was proposed by several groups to answer the question of where the masses of elementary particles come from; this particle is usually referred to as the Higgs particle or the Higgs boson. In July 2012, this Higgs particle was finally found experimentally, a feat accomplished by the ATLAS Collaboration and the CMS Collaboration using the Large Hadron Collider at CERN. It is the purpose of this review to give my personal perspective on a brief history of the experimental search for this particle since the '80s and finally its discovery in 2012. Besides the early searches, those at the LEP collider at CERN, the Tevatron Collider at Fermilab, and the Large Hadron Collider at CERN are described in some detail. This experimental discovery of the Higgs boson is often considered to be the most important advance in particle physics in the last half a century, and some of the possible implications are briefly discussed. This review is partially based on a talk presented by the author at the ...

The large hadron collider project

International Nuclear Information System (INIS)

Maiani, L.

1999-01-01

Knowledge of the fundamental constituents of matter has greatly advanced, over the last decades. The standard theory of fundamental interactions presents us with a theoretically sound picture, which describes with great accuracy known physical phenomena on most diverse energy and distance scales. These range from 10 -16 cm, inside the nucleons, up to large-scale astrophysical bodies, including the early Universe at some nanosecond after the Big-Bang and temperatures of the order of 10 2 GeV. The picture is not yet completed, however, as we lack the observation of the Higgs boson, predicted in the 100-500 GeV range - a particle associated with the generation of particle masses and with the quantum fluctuations in the primordial Universe. In addition, the standard theory is expected to undergo a change of regime in the 10 3 GeV region, with the appearance of new families of particles, most likely associated with the onset of a new symmetry (supersymmetry). In 1994, the CERN Council approved the construction of the large hadron collider (LHC), a proton-proton collider of a new design to be installed in the existing LEP tunnel, with an energy of 7 TeV per beam and extremely large luminosity, of ∝10 34 cm -2 s -1 . Construction was started in 1996, with the additional support of the US, Japan, Russia, Canada and other European countries, making the LHC a really global project, the first one in particle physics. After a short review of the physics scenario, I report on the present status of the LHC construction. Special attention is given to technological problems such as the realization of the super-conducting dipoles, following an extensive R and D program with European industries. The construction of the large LHC detectors has required a vast R and D program by a large international community, to overcome the problems posed by the complexity of the collisions and by the large luminosity of the machine. (orig.)

Colliding muons

International Nuclear Information System (INIS)

Anon.

1994-01-01

Is a muon-muon collider really practical? That is the question being asked by Bob Palmer. Well known in particle physics, Palmer, with Nick Samios and Ralph Shutt, recently won the American Physical Society's Panofsky Prize for their 1964 discovery of the omega minus. As well as contributing to other major experiments, both at CERN and in the US, he has contributed ideas to stochastic cooling and novel acceleration schemes

The 20th Hadron Collider Physics Symposium in Evian

CERN Multimedia

Ludwik Dobrzynski and Emmanuel Tsesmelis

The 20th Hadron Collider Physics Symposium took place in Evian from 16 to 20 November 2009. The Hadron Collider Physics Symposium series has been a major forum for presentations of physics at the Tevatron over the past two decades. The merger of the former Topical Conference on Hadron Collider Physics with the LHC Symposium in 2005 brought together the Tevatron and LHC communities in a single forum. The 20th Hadron Collider Physics Symposium took place in Evian, on the shores of Lake Geneva, from 16-20 November 2009, some 17 years after the historic ECFA-CERN Evian meeting in March 1992 when Expressions of Interest for LHC detectors were presented for the first time. The 2009 event was organized jointly by CERN and the French high-energy physics community (CNRS-IN2P3 and CEA-IRFU). More than 170 people registered for this symposium. This year’s symposium was held at an important time for both the Tevatron and the LHC. It stimulated the completion of analyses for a significant Tevatron data sam...

CERN - the W and the LHC

CERN Document Server

Rodgers, P

2003-01-01

Construction of the Large Hadron Collider (LHC) and its detectors at the CERN laboratory in Geneva is a challenge of Himalayan proportions. The LHC will collide protons at energies of 14 TeV (14 million million electrons volts) and two detectors - ATLAS and CMS - will survey the debris of these collisions for signs of the Higgs boson, supersymmetric particles, large extra dimensions and other evidence of new physics beyond the Standard Model. (U.K.)

Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

Science.gov (United States)

Bruce, R.; Assmann, R. W.; Boccone, V.; Bracco, C.; Brugger, M.; Cauchi, M.; Cerutti, F.; Deboy, D.; Ferrari, A.; Lari, L.; Marsili, A.; Mereghetti, A.; Mirarchi, D.; Quaranta, E.; Redaelli, S.; Robert-Demolaize, G.; Rossi, A.; Salvachua, B.; Skordis, E.; Tambasco, C.; Valentino, G.; Weiler, T.; Vlachoudis, V.; Wollmann, D.

2014-08-01

The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010-2013, the LHC was routinely storing protons at 3.5-4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An uncontrolled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multistage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the collimation system. The studies include tracking of protons through the fields of more than 5000 magnets in the 27 km LHC ring over hundreds of revolutions, and Monte Carlo simulations of particle-matter interactions both in collimators and machine elements being hit by escaping particles. The simulation results agree typically within a factor 2 with measurements of beam loss distributions from the previous LHC run. Considering the complex simulation, which must account for a very large number of unknown imperfections, and in view of the total losses around the ring spanning over 7 orders of magnitude, we consider this an excellent agreement. Our results give confidence in the simulation tools, which are used also for the design of future accelerators.

Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

Directory of Open Access Journals (Sweden)