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Future colliders

Description: The high energy physics advantages, disadvantages and luminosity requirements of hadron (pp, pp), of lepton (e{sup +}e{sup {minus}}, {mu}{sup +} {mu}{sup {minus}}) and photon-photon colliders are considered. Technical arguments for increased energy in each type of machine are presented. Their relative size, and the implications of size on cost are discussed.
Date: October 1, 1996
Creator: Palmer, R.B. & Gallardo, J.C.
Partner: UNT Libraries Government Documents Department

Lepton accelerators and radiation sources: R and D investment at BNL

Description: Brookhaven National Laboratory (BNL) has shown its determination to remain at the forefront of accelerator based science through its continued investment in long range accelerator R and D. The laboratory has a broad program in accelerator technology development including projects such as high {Tc} magnets at RHIC, Siberian Snakes at the AGS, brightness upgrades on the NSLS storage ring, and spallation source R and D in several departments. This report focuses on a segment of the overall program: the lepton accelerator and coherent radiation source R and D at the laboratory. These efforts are aimed at (1) development of high brightness electron beams, (2) novel acceleration techniques, (3) seeded Free Electron Laser (FEL) development, and (4) R and D for a muon collider. To pursue these objectives, BNL ha over the past decade introduced new organizational arrangements. The BNL Center for Accelerator Physics (CAP) is an interdepartmental unit dedicated to promoting R and D which, cannot be readily conducted within the programs of operating facilities. The Accelerator Test Facility (ATF) is managed by CAP and NSLS as a user facility dedicated to accelerator and beam physics problems of interest to both the High Energy Physics and Basic Energy Sciences programs of the DOE. Capitalizing on these efforts, the Source Development Laboratory (SDL) was established by the NSLS to facilitate coordinated development of sources and experiments to produce and utilize coherent sub-picosecond synchrotron radiation. This White Paper describes the programs being pursued at CAP, ATF and SDL aimed at advancing basic knowledge of lepton accelerators and picosecond radiation sources.
Date: March 1, 1997
Creator: Ben-Zvi, I.; Fernow, R.; Gallardo, J.; Hart, M.; Hastings, J.; Johnson, E. et al.
Partner: UNT Libraries Government Documents Department

Discovery potential for new phenomena

Description: The authors examine the ability of future facilities to discover and interpret non-supersymmetric new phenomena. The authors first explore explicit manifestations of new physics, including extended gauge sectors, leptoquarks, exotic fermions, and technicolor models. They then take a more general approach where new physics only reveals itself through the existence of effective interactions at lower energy scales.
Date: March 1, 1997
Creator: Godfrey, S.; Hewett, J.L. & Price, L.E.
Partner: UNT Libraries Government Documents Department

High luminosity particle colliders

Description: The authors consider the high energy physics advantages, disadvantages and luminosity requirements of hadron (pp, p{anti p}), lepton (e{sup +}e{sup {minus}}, {mu}{sup +}{mu}{sup {minus}}) and photon-photon colliders. Technical problems in obtaining increased energy in each type of machine are presented. The machines relative size are also discussed.
Date: March 1, 1997
Creator: Palmer, R.B. & Gallardo, J.C.
Partner: UNT Libraries Government Documents Department

Theory of multi-electron recoil effects on x-ray lineshapes of metals

Description: Within the change of self-consistent field approximation, x-ray spectra can be considerably richer in many-electron phenomena than once suspected. With the finite number of electrons method, these spectra can be evaluated for realistic electron-hole interactions in free electron metals. Preliminary results indicate that metals with band structure can also be treated this way. However, theories of final-state interactions in metals await the reliable determinations of the screened potential of a core hole in a metal and realistic avaluation of the effects of electron-electron interactions. (GHT)
Date: January 1, 1980
Creator: Dow, J. D.; Swarts, C. A.; Bowen, M. A.; Mehreteab, E. & Satpathy, S. S.
Partner: UNT Libraries Government Documents Department

Physics, Computer Science and Mathematics Division. Annual report, January 1-December 31, 1980

Description: Research in the physics, computer science, and mathematics division is described for the year 1980. While the division's major effort remains in high energy particle physics, there is a continually growing program in computer science and applied mathematics. Experimental programs are reported in e/sup +/e/sup -/ annihilation, muon and neutrino reactions at FNAL, search for effects of a right-handed gauge boson, limits on neutrino oscillations from muon-decay neutrinos, strong interaction experiments at FNAL, strong interaction experiments at BNL, particle data center, Barrelet moment analysis of ..pi..N scattering data, astrophysics and astronomy, earth sciences, and instrument development and engineering for high energy physics. In theoretical physics research, studies included particle physics and accelerator physics. Computer science and mathematics research included analytical and numerical methods, information analysis techniques, advanced computer concepts, and environmental and epidemiological studies. (GHT)
Date: December 1, 1981
Creator: Birge, R.W.
Partner: UNT Libraries Government Documents Department

The rise of colliding beams

Description: It is a particular pleasure for me to have this opportunity to review for you the rise of colliding beams as the standard technology for high-energy-physics accelerators. My own career in science has been intimately tied up in the transition from the old fixed-target technique to colliding-beam work. I have led a kind of double life both as a machine builder and as an experimenter, taking part in building and using the first of the colliding-beam machines, the Princeton-Stanford Electron-Electron Collider, and building the most recent advance in the technology, the Stanford Linear Collider. The beginning was in 1958, and in the 34 years since there has been a succession of both electron and proton colliders that have increased the available center-of-mass energy for hard collisions by more than a factor of 1000. For the historians here, I regret to say that very little of this story can be found in the conventional literature. Standard operating procedure for the accelerator physics community has been publication in conference proceedings, which can be obtained with some difficulty, but even more of the critical papers are in internal laboratory reports that were circulated informally and that may not even have been preserved. In this presentation I shall review what happened based on my personal experiences and what literature is available. I can speak from considerable experience on the electron colliders, for that is the topic in which I was most intimately involved. On proton colliders my perspective is more than of an observer than of a participant, but I have dug into the literature and have been close to many of the participants.
Date: June 1, 1992
Creator: Richter, B.
Partner: UNT Libraries Government Documents Department

New approach to high energy SU/sub 2L/ /times/ U/sub 1/ radiative corrections

Description: We present a new approach to SU/sub 2L/ /times/ U/sub 1/ radiative corrections at high energies. Our approach is based on the infrared summation methods of Yennie, Frautschi and Suura, taken together with the Weinberg-'t Hooft renormalization group equation. Specific processes which have been realized via explicit Monte Carlo algorithms are e/sup +/e/sup /minus// ..-->.. f/bar f/' + n(..gamma..), f = ..mu.., /tau/, d, s, u, c, b or t and e/sup +/e/sup /minus// ..-->.. e/sup +/e/sup /minus// + n(..gamma..), where n(..gamma..), denotes multiple photo emission on an event-by-event basis. Exemplary Monte Carlo data are presented. 16 refs., 4 figs.
Date: July 1, 1988
Creator: Ward, B.F.L.
Partner: UNT Libraries Government Documents Department

Adiabatic disruption of asymmetric colliding beams

Description: A scheme is considered for enhancing the luminosity of electron-positron colliders. One of the beams is taken to be much denser than the other and effectively becomes a lens for the second beam. The luminosity enhancement afforded by this asymmetric disruption process is estimated analytically. The scheme is severely limited by the kink instability which is characterized by a two-stream dispersion relation, and a constraint on the density of the less dense beam is found for which the instability is gradient stabilized.
Date: January 1, 1991
Creator: Katsouleas, T. (University of Southern California, Los Angeles, CA (United States). Dept. of Electrical Engineering Electrophysics) & Wurtele, J.S. (Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics)
Partner: UNT Libraries Government Documents Department

Coulomb correlation effects in quasi-one-dimensional conductors

Description: Recent results on the role of electron-electron (e-e) interactions - ''correlation effects'' - in quasi-one-dimensional conductors are reviewed. Within the Peierls-Hubbard model, the consequences of short range (on-site U and nearest neighbor V) e-e interactions for ground state properties, nonlinear excitations, and optical absorption are examined. Techniques include quantum Monte Carlo and weak and strong coupling perturbative arguments. 26 refs., 2 figs.
Date: January 1, 1986
Creator: Campbell, D.K.; Baeriswyl, D. & Mazumdar, S.
Partner: UNT Libraries Government Documents Department

Problems in neutrino electron scattering with 1-GeV neutrinos

Description: Neutrino physics has often been limited by lack of events. This limitation has been not so much for events in total, but for events in selected channels. The basic strategy for dealing with this issue has been to build massive detectors in which target and event detection have been combined. This strategy has been very successful, but it does carry the difficulty that, given a large detector mass, financial limitations apply to the detail with which events may be detected and reconstructed. At KAON some of these difficulties will be alleviated by the increase in neutrino flux, which may make the construction of smaller and more specialized detectors feasible. At the Lake Louise workshop a great deal of interest was expressed in neutrino electron scattering; we shall describe here the limitations of the BNL detector as they emerged in the measurement of sin {sup 2}{Theta}{sub w} at BNL. In this context the knowledge of the beam was an intrinsic part of this experimental systematic errors, and we start with a description of the beam.
Date: January 1, 1992
Creator: White, D.H.
Partner: UNT Libraries Government Documents Department

Panel discussion on laboratory accelerator programs: present and future

Description: The present SLAC accelerator program is summarized briefly, and the future of electron-positron colliders is discussed. Present activities discussed include the PEP storage ring, the SPEAR storage ring, the Linear Accelerator, and the SLAC Linear Collider (SLC) project. Future prospects include a larger scale linear collider. The stability requirements on acceleration are briefly discussed. (LEW)
Date: September 1, 1986
Creator: Richter, B.
Partner: UNT Libraries Government Documents Department

Signatures of supersymmetry in e+e/sup -/ collisions

Description: To date a number of searches for evidence for supersymmetry in electron-positron collisions have been made, all with negative results. The techniques used in these searches are reviewed, and their results are examined. The general theoretical and experimental features of supersymmetry are reviewed briefly. 43 refs., 60 figs. (LEW)
Date: March 1, 1986
Creator: Burke, D.L.
Partner: UNT Libraries Government Documents Department

Attaining high luminosity in linear e sup + e sup minus colliders

Description: The attainment of high luminosity in linear colliders is a complex problem because of the interdependence of the critical parameters. For instance, changing the number of particles per bunch affects the damping ring design and thus the emittance; it affects the wakefields in the linac and thus the momentum spread; the momentum spread affects the final focus design and thus the final {beta}*; but the emittance change also affects the final focus design; and all these come together to determine the luminosity, disruption and beamstrahlung at the intersection. Changing the bunch length, or almost any other parameter, has a similar chain reaction. Dealing with this problem by simple scaling laws is very difficult because one does not know which parameter is going to be critical, and thus which should be held constant. One can only maximize the luminosity by a process of search and iteration. The process can be facilitated with the aid of a computer program. Examples can then be optimized for maximum luminosity, and compared to the optimized solutions with different approaches. This paper discusses these approaches.
Date: November 1, 1990
Creator: Palmer, R.B.
Partner: UNT Libraries Government Documents Department

Supersymmetry: proceedings

Description: Some lectures in these proceedings examine the theoretical basis for supersymmetry, recent developments in theories with compact dimensions, and experimental searches for supersymmetric signatures. Technologies are explored for obtaining very high energy electron-positron colliding beams. Separate abstracts were prepared for 35 papers in these conference proceedings. (LEW)
Date: July 1, 1985
Creator: Brennan, E.C. (ed.)
Partner: UNT Libraries Government Documents Department

Wakefield measurements of SLAC linac structures at the Argonne AATF

Description: Damped and detuned linac structures designed to minimize the effects of wakefields excited by e{sup {plus minus}} bunch trains in future linear colliders are presently under investigation at SLAC. This paper describes the results of measurements of both longitudinal and transverse wakefields performed at the ANL Advanced Accelerator Test Facility with two SLAC-built X-Band disk-loaded waveguides: a conventional 30-cavity long constant-impedance structure and a non-conventional 50-cavity long structure along which the iris and spacer diameters have been varied so as to stagger-tune the HEM{sub 11} mode frequency by 37%. The results are shown to be in excellent agreement with computations made by KN7C, TRANSVRS, TBCI, and LINACBBU. 8 refs., 5 figs.
Date: May 1, 1991
Creator: Wang, J.W.; Loew, G.A. (Stanford Linear Accelerator Center, Menlo Park, CA (USA)); Simpson, J.; Chojnacki, E.; Gai, W.; Konecny, R. et al.
Partner: UNT Libraries Government Documents Department

First results from Mark II at SPEAR

Description: First results from the SLAC-LBL Mark II magnetic detector at SPEAR are presented. The performance of the detector is discussed and preliminary results are given on inclusive baryon production R/sub p + anti p/, R/sub ..lambda.. + anti ..lambda../, on decay modes of the D mesons and on two-photon production of eta' mesons.
Date: May 1, 1979
Creator: Abrams, G.S.; Alam, M.S. & Blocker, C.A.
Partner: UNT Libraries Government Documents Department

Higher luminosities via alternative incident channels

Description: We show that PEP provides some unique opportunities for one and two photon physics with real photons as well as for QCD studies with internal targets. Photon beams would avoid the major limitation on the luminosity of present machines and could provide PEP an ideal b-physics factory producing the full range of J/sub c//sup PC/ and J/sub b//sup PC/ states that may not be observable otherwise as well as allow a whole new class of ''missing-mass'' experiments. These latter particles are the pseudo-Goldstone bosons and their supersymmetric counterparts. These and related possibilities like a single-pass, ''free electron laser'' facility or even synchrotron radiation beam lines all favor a mini-maxi configuration for the low-beta insertions in PEP. This allows more diverse experiments without excluding any ongoing experimental programs. Such possibilities have interesting implications for a number of proposed facilities including the SSC. Some systematic machine physics studies over a range of energies are suggested. 24 refs., 6 figs.
Date: April 1, 1985
Creator: Spencer, J.E.
Partner: UNT Libraries Government Documents Department

SLAC linear collider

Description: A brief description of the proposed SLAC Linear Collider is given. This machine would investigate the possibilities and limitations of Linear Colliders while at the same time producing thousands of Z/sup 0/ particles per day for the study of the weak interactions.
Date: June 1, 1980
Creator: Hollebeek, R.
Partner: UNT Libraries Government Documents Department

Tangent map analysis of the beam-beam interaction

Description: We studied the tangent map of the beam-beam interaction and found no evidence of beam-beam instability for /epsilon/ = 0.04. Tracking study with tune modulation shows however large emittance growth due to the sum resonances. The emittance growth is due to the multiple crossing of the sum resonances. 12 refs., 7 figs.
Date: January 1, 1989
Creator: Lee, S.Y. & Tepikian, S.
Partner: UNT Libraries Government Documents Department

Vacuum design for a superconducting mini-collider

Description: The phi factory (Superconducting Mini-Collider or SMC) proposed for construction at UCLA is a single storage ring with circulating currents of 2 A each of electrons and positrons. The small circumference exacerbates the difficulties of handling the gas load due to photo-desorption from the chamber walls. We analyze the vacuum system for the phi factory to specify design choices. 7 refs., 6 figs., 1 tab.
Date: April 9, 1991
Creator: Barletta, W.A. (Lawrence Livermore National Lab., CA (USA)) & Monteiro, S. (Moorpark Coll., CA (USA))
Partner: UNT Libraries Government Documents Department

New particle searches

Description: The Standard Model is a remarkable result of decades of work in particle physics, but it is clearly an incomplete representation of the world. Exploring possibilities beyond the Standard Model is a major preoccupation of both theorists and experimentalists. Despite the many suggestions that are extant about the missing links within the Standard Model as well as extensions beyond it, no hard experimental evidence exists. In particular, in more than five years of experimentation both at PETRA and PEP no new particles have been found that would indicate new physics. Several reasons are possible for these negative results: the particles may be too heavy; the experiments may not be looking in the proper way; the cross sections may be too small or finally the particles may not exist. A continuing PEP program, at high luminosity will ensure that the second and third reason continue to be addressed. The higher energy e/sup +/e/sup -/ storage rings such as TRISTAN and LEP will extend the mass limits. High mass particles can also be produced at the CERN collider and soon with the Tevatron collider. A concise summary of the mass limits from the PETRA experiments has been given in a recent Mark J publication. The results shown provide a convenient yardstick against which to measure future search experiments.
Date: January 1, 1985
Creator: Derrick, M.
Partner: UNT Libraries Government Documents Department

e/sup +/-e/sup -/ hadronic multiplicity distributions

Description: The 29 GeV multiplicity data have been analyzed for e/sup +/ -e/sup -/ ..-->.. hadrons using the partially coherent laser distribution (PCLD). The latter interpolates between the negative binomial and Poisson distributions as the ratio S/N of coherent/incoherent multiplcity varies from zero to infinity. The negative binomial gives an excellent fit for rather large values of the cell parameter k. Equally good fits (for full and partial rapidity range, and for the forward/backward 2 jet correlation) are obtained for the mostly coherent (almost Poissonian) PCLD with small values of k (equal to the number of jets). The reasons for the existence of this tradeoff are explained in detail. The existence of the resulting ambiguity is traced to the insensitivity of the probability distribution to phase information in the hadronic density matrix. The study of higher order correlations (intensity interferometry) among like sign-particles is recommended to resolve this question.
Date: January 1, 1986
Creator: Carruthers, P. & Shih, C.C.
Partner: UNT Libraries Government Documents Department