Ultimate luminosities and energies of photon colliders
Valery Telnov
备注：
15 pages, Latex, 6 figures(eps), submitted to Proceedings of the Symposium on Future High Energy Colliders, ITP, UCSB, Santa Barbara, October 1996. AIP Press
A photon collider luminosity and its energy are determined by the parameters of an electron-electron linear collider (energy, power, beam emittances) and collision effects. The main collision effect is the coherent e+e- pair creation. At low energies (2E < 0.5 - 1 TeV) this process is suppressed due to repulsion of electron beams. In this region gamma-gamma luminosity above 10^{35} cm-2 s-1 is possible (10^{33} is sufficient). At higher energies the limited average beam power and coherent pair creation restrict the maximum energy of photon colliders (with sufficient luminosity) at 2E ~ 5 TeV. Obtaining high luminosities requires the development of new methods of production beams with low emittances such as a laser cooling.
Methods of gamma-gamma, gamma-electron luminosities measurement at photon colliders based on Compton scattering of laser photons on high energy electrons at linear colliders are considered.
Luminosities of muon-proton and muon-nucleus collisions at a recently proposed muon-ion collider (MuIC) at Brookhaven National Laboratory (BNL) in the USA have been estimated using A Luminosity Optimizer for High Energy Physics (AloHEP) software keeping in mind beam-beam tune-shift values. It is shown that L$_{μp}$ = 3.6x10$^{31}$ cm$^{-2}$s$^{-1}$ and L$_{μ{\rm -Au}}$ = 2.84x10$^{27}$ cm$^{-2}$s$^{-1}$ values can be achieved at MuIC. The physics search potential of the collider is superior to HERA. However, LHeC will provide 2 orders of higher luminosities at approximately same center-of-mass…
With seven operational colliders in the world and two under construction, the international particle physics community not only actively explores options for the next facilities for detailed studies of the Higgs/electroweak physics and beyond-the-LHC energy frontier, but also seeks a clear picture of the limits of the colliding beams method. In this paper, we try to consolidate various recent efforts in identifying physics limits of colliders in conjunction with societal sustainability, and share our thoughts about the perspective of reaching the ultimate collider that is at the quantum limit.
Particle colliders have been remarkably successful tools in particle and nuclear physics. What are the future trends and limitations of accelerators as they currently exist, and are there possible alternative approaches? What would the ultimate collider look like? This talk examines some challenges and possible solutions. Accelerating a single particle rather than a thermal distribution may allow exploration of more controlled interactions without background. Also, cost drivers are possibly the most important limiting factor for large accelerators in the foreseeable future so emerging technolo…
Different limitations on luminosity of linac-ring type colliders coming from beam dynamics issues are considered for the examples of the $ep$ options of the THERA and LinacXLHC proposals. It is shown that $L=1.3\times 10^{31}$ for THERA and $L=2.7\times 10^{32}$ for LinacXLHC can be achieved for round beams case. Corresponding sets of parameters are given with the explanations.
REBCO tape has remarkable performance for super-conducting technology, but it is extremely expensive and it is a strongly anisotropic superconductor. The design of a 3.5 T collider dipole is presented in which all turns of the body winding are oriented so that the all turns of REBCO tape operate with maximum current density. Each turn within the winding contains a stack of Cu-clad REBCO tapes; all tapes within the turn are compressed to provide low-resistance Cu-Cu contact, but the successive turns are electrically isolated. Each turn is oriented so that the local magnetic field at the tapes i…
Concerning future lepton-nucleus colliders, International Linear Collider (ILC) and Plasma Wake Field Accelerator-Linear Collider (PWFA-LC) electrons in order of 0.5 TeV and 5 TeV, respectively, colliding with Super proton-proton Collider (SppC)'s 3075 TeV lead ions, are considered as "linac-ring eA" options. In addition, 1.5 TeV option of the Muon Collider (MC) vs 3075 TeV lead ions of the SppC is also taken into account as a "ring-ring muA" collider. Luminosity values of the SppC-based eA and muA colliders are estimated. 3075 TeV lead parameters for 100 km-circumference option of the SppC ar…
At linear colliders, the e+e- luminosity is limited by beam-collision effects, which determine the required emittances of beams in damping rings (DRs). While in gamma-gamma collisions at the photon collider, these effects are absent, and so smaller emittances are desirable. In present damping rings designs, nominal DR parameters correspond to those required for e+e- collisions. In this note, I would like to stress once again that as soon as we plan the photon-collider mode of ILC operation, the damping-ring emittances are dictated by the photon-collider requirements--namely, they should be as …
Linear colliders offer a unique possibility to study gamma gamma and gamma electron interactions at the energies 0.1--2 TeV. This option is now included in design reports of NLC, JLC and TESLA/SBLC. This paper includes: status of photon colliders, new possibilities in study of Higgs boson, ways to achieve high luminosities.
Photon collider based on cold and warm linear collider technologies are compared from the point of view of attainable luminosities, technical feasibility of laser systems and experimental conditions.
Particle loss due to the emission of single energetic beamstrahlung photons in beam collisions is shown to impose a fundamental limit on storage-ring luminosities at energies greater than 2E~140 GeV for head-on collisions and 2E~40 GeV for crab-waist collisions. Above these threshold energies, the suppression factor due to beamstrahlung scales as 1/E^{4/3}, and for a fixed power of synchrotron radiation, the luminosity L is proportional to R/E^{13/3}, where R is the collider radius. For 2E > 150 GeV, both collision schemes have similar luminosity limits. The luminosities attainable at storage-…
In this study, main parameters of Super proton-proton Collider (SppC) based lepton-proton colliders are estimated. For electron beam parameters, highest energy International Linear Collider (ILC) and Plasma Wake Field Accelerator-Linear Collider (PWFA-LC) options are taken into account. For muon beams, 1.5 TeV and 3 TeV center of mass energy Muon Collider parameters are used. In addition, ultimate $μ$p collider which assumes construction of additional 50 TeV muon ring in the SppC tunnel is considered as well. It is shown that $L_{ep}$ $\sim$ $10^{32}$ $cm^{-2}s^{-1}$ can be achieved with moder…
It is very likely that in 3-4 years the construction of one or two linear colliders with c.m.s energy up to 0.5--1.5 TeV will be started. Besides e^+e^- collisions, linear colliders give a unique possibility to study gamma-gamma and gamma-electron interactions at energies and luminosities comparable to those in e^+e^- collisions. High energy photons for gamma-gamma and gamma-electron collisions can be obtained using laser backscattering. These types of collisions considerably increase the physics potential of linear colliders for relatively a small incremental cost. This report briefly reviews…
A strong candidate for the Standard Model Scalar boson, H(126), has been discovered by the Large Hadron Collider (LHC) experiments. In order to study this fundamental particle with unprecedented precision, and to perform precision tests of the closure of the Standard Model, we investigate the possibilities offered by An e+e- storage ring collider. We use a design inspired by the B-factories, taking into account the performance achieved at LEP2, and imposing a synchrotron radiation power limit of 100 MW. At the most relevant centre-of-mass energy of 240 GeV, near-constant luminosities of 10^34 …
High energy photon colliders based on laser backscattering are a very natural extension of a e+e- linear colliders and open new possibilities to study of the matter. This option has been included in the pre-conceptual designs of linear colliders and work on Technical Design Reports is in progress. The physics motivation for photon colliders is quite clear though more studies are needed. The proof of its technical feasibility and the search for the best solutions is of first priority now. In this talk we discuss: physics motivation, laser problems and new possible solutions, and generation of l…
C. B. Schroeder, E. Esarey, C. Benedetti, and W. P. Leemans {Phys. Rev. ST Accel. Beams 13, 101301 (2010) and 15, 051301 (2012)} have proposed a set of parameters for a TeV-scale collider based on plasma wake field accelerator principles. In particular, it is suggested that the luminosities greater than 10^34 cm-2s-1 are attainable for an electron-positron collider. In this comment we dispute this set of parameters on the basis of first principles. The interactions of accelerating beam with plasma impose fundamental limitations on beam properties and, thus, on attainable luminosity values.
The Tevatron in Collider Run II (2001-present) is operating with six times more bunches and many times higher beam intensities and luminosities than in Run I (1992-1995). Beam diagnostics were crucial for the machine start-up and the never-ending luminosity upgrade campaign. We present the overall picture of the Tevatron diagnostics development for Run II, outline machine needs for new instrumentation, present several notable examples that led to Tevatron performance improvements, and discuss the lessons for future colliders.
Since the initial development of charged particle colliders in the middle of the 20th century, these advanced scientific instruments have been at the forefront of scientific discoveries in high energy physics. Collider accelerator technology and beam physics have progressed immensely and modern facilities now operate at energies and luminosities many orders of magnitude greater than the pioneering colliders of the early 1960s. In addition, the field of colliders remains extremely dynamic and continues to develop many innovative approaches. Indeed, several novel concepts are currently being con…
The Compact Linear Collider (CLIC) is a proposed high-luminosity collider that would collide electrons with their antiparticles, positrons, at energies ranging from a few hundred Giga-electronvolts (GeV) to a few Tera-electronvolts (TeV). By covering a large energy range and by ultimately reaching multi-TeV $e^+e^-$ collisions, scientists at CLIC aim to improve the understanding of nature's fundamental building blocks and to discover new particles or other physics phenomena. CLIC is an international project with institutes world-wide participating in the accelerator, detector and physics studi…
A novel method of electron beam cooling is considered which can be used for linear colliders. The electron beam is cooled during collision with focused powerful laser pulse. With reasonable laser parameters (laser flash energy about 10 J) one can decrease transverse beam emittances by a factor about 10 per one stage. The ultimate transverse emittances are much below those achievable by other methods. Beam depolarization during cooling is about 5--15 % for one stage. This method is especially useful for photon colliders and opens new possibilities for e+e- colliders.
Based on current CERN infrastructure, an electron-proton collider is proposed at a centre-of-mass energy of about 9 TeV. A 7 TeV LHC bunch is used as the proton driver to create a plasma wakefield which then accelerates electrons to 3 TeV, these then colliding with the other 7 TeV LHC proton beam. The basic parameters of the collider are presented, which although of very high energy, has integrated luminosities of the order of 1 pb$^{-1}$/year. For such a collider, with a centre-of-mass energy 30 times greater than HERA, parton momentum fractions, $x$, down to about $10^{-8}$ are accessible fo…
In high energy physics, the luminosity is one useful value to characterize the performance of a particle collider. To gain more available data, we need to maximize the luminosity in most collider experiments. With the discussions of tune shift involved the beam dynamics and a recently proposed "crabbed waist" scheme of beam-beam collisions, we present some qualitative analysis to increase the luminosity. In addition, beam-beam tune shifts and luminosities of $e^{+}e^{-}$, $pp$/$p\bar{p}$, and $μ^{+}μ^{-}$ colliders are discussed.
A method of electron beam cooling is considered which can be used for linear colliders. The electron beam is cooled during collision with focused powerful laser pulse. The ultimate transverse emittances are much below those achievable by other methods. This method is especially useful for high energy gamma-gamma colliders. In this paper we review and analyse limitations in this method, also discuss a new method of obtaining very high laser powers required for the laser cooling, radiation conditions and finaly present a possible scheme for the laser cooling of electron beams.
Linear colliders (LC) on the energy 0.5-1 TeV are considered as the next step in the particle physics. High acceleration gradients, small beam sizes, precision tolerances, beam collision effects are main problems for linear colliders. In this paper we discuss physics motivation, parameters and status of current LC projects, e+e-, gamma-gamma and gamma-electron modes of operation, physical limitations on the energy and luminosity. Present technologies allow to reach energies about 5 TeV with adequate luminosities. Advanced technique based on plasma and laser method of acceleration can provide m…
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 design luminosity of the Tevatron was 1030 cm-2 s-1; however, as a result of two decades of upgrades, the accelerator has been able to deliver 430-times higher luminosities to each of two high-luminosity experiments, Collider Detector at Fermilab (CDF) and D0. On the way to record high luminosities, many issues related to the electromagnetic beam-beam interact…
Discoveries at high-energy particle colliders have established the standard model of particle physics. Technological innovation has helped to increase the collider energy at a much faster pace than the corresponding costs. New concepts will allow reaching ever higher luminosities and energies throughout the coming century. Cost-effective strategies for the collider implementation include staging. For example, a future circular collider could first provide electron-positron collisions, then hadron collisions (proton-proton and heavy-ion), and finally the collision of muons. Cooling-free muon co…
A high energy photon collider (gamma-gamma, gamma-electron) based on backward Compton scattering of laser light is a very natural supplement to e+e- a linear collider and can significantly enrich the physics program. The region below about one 0.5-1 TeV is very convenient from a technical point of view: wave length of the laser should be about 1 micron, i.e. in the region of most powerful solid state lasers, collision effects do not restrict the gamma-gamma luminosity. In the multi-TeV energy region the situation is more complicated: the optimum laser wave length increases in proportionally wi…
Intrabeam scattering studies with large-emittance-ratio ion beams in the Relativistic Heavy Ion Collider, and implications for the Electron-Ion Collider
Particle acceleration in dielectric microstructures powered by infrared lasers, or "dielectric laser acceleration" (DLA), is a promising area of advanced accelerator research with the potential to enable more affordable and higher-gradient accelerators for energy frontier science and a variety of other applications. DLA leverages well-established industrial fabrication capabilities and the commercial availability of tabletop lasers to reduce cost, with axial accelerating fields in the GV/m range. Desirable luminosities would be obtained by operating with very low charge per bunch but at extrem…
The international Future Circular Collider (FCC) study aims at a design of $pp$, $e^+e^-$, $ep$ colliders to be built in a new 100 km tunnel in the Geneva region. The $e^+e^-$ collider (FCC-ee) has a centre of mass energy range between 90 (Z-pole) and 375 GeV (tt_bar). To reach such unprecedented energies and luminosities, the design of the interaction region is crucial. The crab-waist collision scheme has been chosen for the design and it will be compatible with all beam energies. In this paper we will describe the machine detector interface layout including the solenoid compensation scheme. …
Last two years were very important in history of a photon colliders. This option is included now in conceptual design reports of the NLC, JLC and TESLA/SBLC projects. All the designs foresee two interaction regions: one for e+e- and the second for gamma-gamma, gamma-e and e^-e^- collisions. This paper is focused on three aspects: 1) arguments for photon colliders; 2) parameters of current projects; 3) ultimate luminosities and energies, new ideas. Recent studies have shown that the main collision effect - coherent pair creation - is suppressed at photon colliders with the energy (2E < 2 TeV) d…
Interest in highly-compressed electron beams has been increasing in recent times, driven by the study of non-linear and even non-perturbative aspects of QED [2]. The FACET-II [7] facility at SLAC is currently (at the time of writing) being constructed and has been predicted to be able to deliver unprecedented peak beam intensities (>200 kA). We consider here what might be possible in pushing the bunch length compression to its limits at a future Linear Collider facility based on experience at FACET and ongoing photo-injector designs. We present an alternative electron-electron collision parame…
High energy particle colliders have been in the forefront of particle physics for more than three decades. At present the near term US, European and international strategies of the particle physics community are centered on full exploitation of the physics potential of the Large Hadron Collider (LHC) through its high-luminosity upgrade (HL-LHC). A number of next generation collider facilities have been proposed and are currently under consideration for the medium- and far-future of the accelerator-based high energy physics. In this paper we offer a uniform approach to evaluation of various acc…
Muon Collider (MC) - proposed by G. I. Budker and A. N. Skrinsky a few decades ago - is now considered as the most exciting option for the energy frontier machine in the post-LHC era. A national Muon Accelerator Program (MAP) is being formed in the USA with the ultimate goal of building a MC at the Fermilab site with c.o.m. energy in the range 1.5-3 TeV and luminosity of ~1-5 \times 10^{34} cm^{-2}s^{-1}1. As the first step on the way to MC it envisages construction of a Neutrino Factory (NF) for high-precision neutrino experiments. The baseline scheme of the NF-MC complex is presented and pos…
The backward Compton scattering is a basic process at future higher energy photon colliders. To obtain a high probability of e->gamma conversion the density of laser photons in the conversion region should be so high that simultaneous interaction of one electron with several laser photons is possible (nonlinear Compton effect). In this paper a detailed consideration of energy spectra, helicities of final photons and electrons in nonlinear backward Compton scattering of circularly polarized laser photons is given. Distributions of gamma-gamma luminosities with total helicities 0 and 2 are inves…
Since 1960's, particle colliders have been in the forefront of particle physics, 29 total have been built and operated, 7 are in operation now. At present the near term US, European and international strategies of the particle physics community are centered on full exploitation of the physics potential of the Large Hadron Collider (LHC) through its high-luminosity upgrade (HL-LHC). The future of the world-wide HEP community critically depends on the feasibility of possible post-LHC colliders. The concept of the feasibility is complex and includes at least three factors: feasibility of energy, …
In order to achieve luminosities significantly higher than in existing machines, future storage-ring based colliders will need to operate in novel parameter regimes combining ultra-low emittance, large Piwinski angle and high bunch charge; implementation of techniques such as a "crab waist" will add further challenges. Understanding the beam-beam interaction in these situations will be essential for the design of future very high luminosity colliders. Recent developments in modeling tools for studying beam-beam effects, capable of investigating the relevant regimes, will be discussed and examp…
