相关论文: Observations of beam-beam effects at the LHC

This paper describes two distinct effects observed during the operation of the LHC in 2012: first, the impacts on beam parameter evolution of the end-of-squeeze instabilities encountered in the second half of the 2012 run; and, second, the…

We report on the experience with long-range beam--beam effects in the LHC, in dedicated studies as well as the experience from operation. Where possible, we compare the observations with the expectations.

Investigating the beam-beam limit in the LHC is of great importance, since identifying its source is crucial for the luminosity optimization scenario. Several experiments were carried out to search for this limit and check whether it is…

While well studied in the absence of beam-beam and while colliding head-on, the stability of the LHC beams can be very critical in intermediate steps. During the squeeze, the long-range beam-beam interaction becomes a critical component of…

For high bunch intensities the long-range beam-beam interactions are strong enough to provoke effects on the orbit. As a consequence the closed orbit changes. The closed orbit of an unperturbed machine with respect to a machine where the…

For almost a quarter of a century the Tevatron proton-antiproton collider was the centrepiece of the world's high-energy physics program, from the start of operation in December 1985 until it was overtaken by the LHC in 2011. The initial…

Hosting six different experiments at four different interaction points and widely different requirements for the running conditions, the LHC machine has been faced with a long list of challenges in the first three years of luminosity…

Long-range beam-beam effects are a potential limit to the LHC performance with the nominal design parameters, and certain upgrade scenarios under discussion. To mitigate long-range effects, current carrying wires parallel to the beam were…

An overview of the impact of the first three years of LHC operation on two of the most important open questions in astroparticle physics is presented. Measurements in proton-proton collisions at the energy frontier that provide valuable…

LHC upgrades are being considered both towards higher luminosity (HL-LHC) and towards higher energy (HE-LHC). In this paper we report initial studies of the beam-beam effects in the HE-LHC [1]. The HE-LHC aims at beam energies of 16.5 TeV,…

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…

First thoughts on the design of the beam vacuum system for the High Energy LHC (HE-LHC) are given with a particular focus on the impact of the synchrotron radiation. In the HE-LHC, the vacuum dynamic effects induced by the circulating beams…

The Higher-Energy LHC (HE-LHC) should collide two proton beams of 16.5-TeV energy, circulating in the LHC tunnel. We discuss the main parameter choices, as well as some optics and beam dynamics issues, in particular the time evolution of…

The variety of beams, needed to set-up in the injectors as requested in the LHC, are reviewed, in terms of priority but also performance expectations and reach during 2015. This includes the single bunch beams for machine commissioning and…

One of the most severe limitations in high-intensity particle colliders is the beam-beam interaction, i.e. the perturbation of the beams as they cross the opposing beams. This introduction to beam-beam effects concentrates on a description…

During the recent years of LHC operation, we analysed the situation of beam instrumentation and the need to optimize it for beam-beam studies. The most important beam instrumentation devices will be highlighted and modifications or…

Long-range beam-beam effects occurred in the Tevatron at all stages (injection, ramp, squeeze, and collisions) and affected both proton and antiproton beams. They resulted in beam losses and emittance blow-ups, which occurred in remarkable…

Observations of single bunch beam-beam coherent modes during dedicated experiments in the LHC are presented. Their role in standard operation for physics is discussed and, in particular, candidates of beam-beam coherent mode driven unstable…

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory has been in operation since 2000. Over the past decade, the luminosity in the polarized proton (p-p) operations has increased by more than one order of magnitude.…

This article discusses the physics programme of the TOTEM experiment at the LHC. A new special beam optics with beta* = 90 m, enabling the measurements of the total cross-section, elastic pp scattering and diffractive phenomena already at…