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Backgrounds to the detection of two-body hadronic B decays

Description: We consider backgrounds to the detection of the two-body hadronic decay modes of neutral B mesons and baryons. The largest background is due to the correlated production of pairs of high-p/sub T/ hadrons in the target, but this can be adequately rejected provided the experimental apparatus has sufficient resolution in mass and decay vertex. Another possible source of background arises from the production and decay of charmed and strange particles. Since these particles can travel considerable distances before decaying, they can give rise to backgrounds which may not be rejectable by means of vertex cut. We have simulated several backgrounds from charm, and we find them to be small compared to the expected level of signal. 8 refs., 1 fig., 2 tabs
Date: January 8, 1988
Creator: Kaplan, D.M.; Peng, Jen-Chieh; Abrams, G.S. & Stockdale, I.E.
Partner: UNT Libraries Government Documents Department

Field characterization and personal dosimetry at a high energy ion accelerator

Description: The response of a variety of dosimeters was evaluated in the radiation field outside the shielding of the Lawrence Berkeley Laboratory Bevalac Biomedical Facility. The primary beam was 580 MeV/center dot/A neon ions, incident upon a 30.5-cm polyethylene cube. The field was characterized by a neutron spectrometer consisting of Bonner spheres and other detectors and by estimates of charged particle fluences in NTA film and in the Berklet spectrometer. The responses of American Acrylics CR-39 track-etch plastic detectors and AECL (Canada) type BD-100 Bubble Detectors were compared to those of NTA film, Andersson-Braun remmeter and recombination-chamber results as well as to reference dose equivalents based upon the unfolded neutron spectrum. Evaluations of these dosimeters are discussed. 7 refs., 4 figs.
Date: March 1, 1988
Creator: Greenhouse, N.A.; Busick, D.D.; de Castro, T.M.; Elwyn, A.J.; Hankins, D.E.; Ipe, N.E et al.
Partner: UNT Libraries Government Documents Department

The use of electromagnetic particle-in-cell codes in accelerator applications

Description: The techniques developed for the numerical simulation of plasmas have numerous applications relevant to accelerators. The operation of many accelerator components involves transients, interactions between beams and rf fields, and internal plasma oscillations. These effects produce non-linear behavior which can be represented accurately by particle in cell (PIC) simulations. We will give a very brief overview of the algorithms used in PIC Codes. We will examine the range of parameters over which they are useful. We will discuss the factors which determine whether a two or three dimensional simulation is most appropriate. PIC codes have been applied to a wide variety of diverse problems, spanning many of the systems in a linear accelerator. We will present a number of practical examples of the application of these codes to areas such as guns, bunchers, rf sources, beam transport, emittance growth and final focus. 8 refs., 8 figs., 2 tabs.
Date: December 1, 1988
Creator: Eppley, K.
Partner: UNT Libraries Government Documents Department

Polarization at the SLC

Description: The Stanford Linear collider was designed to accommodate polarized electron beams. Longitudinally polarized electrons colliding with unpolarized positrons at a center of mass energy near the Z/sup 0/ mass can be used as novel and sensitive probes of the electroweak process. A gallium arsenide based photon emission source will provide a beam of longitudinally polarized electrons of about 45 percent polarization. A system of bend magnets and a superconducting solenoid will be used to rotate the spins so that the polarization is preserved while the 1.21 GeV electrons are stored in the damping ring. Another set of bend magnets and two superconducting solenoids orient the spin vectors so that longitudinal polarization of the electrons is achieved at the collision point with the unpolarized positrons. A system to monitor the polarization based on Moller and Compton scattering will be used. Nearly all major components have been fabricated and tested. Subsystems of the source and polarimeters have been installed, and studies are in progress. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. 8 refs., 16 figs., 1 tab.
Date: October 1, 1988
Creator: Moffeit, K.C.
Partner: UNT Libraries Government Documents Department

An essay on discrete foundations for physics

Description: We base our theory of physics and cosmology on the five principles of finiteness, discreteness, finite computability, absolute non- uniqueness, and strict construction. Our modeling methodology starts from the current practice of physics, constructs a self-consistent representation based on the ordering operator calculus and provides rules of correspondence that allow us to test the theory by experiment. We use program universe to construct a growing collection of bit strings whose initial portions (labels) provide the quantum numbers that are conserved in the events defined by the construction. The labels are followed by content strings which are used to construct event-based finite and discrete coordinates. On general grounds such a theory has a limiting velocity, and positions and velocities do not commute. We therefore reconcile quantum mechanics with relativity at an appropriately fundamental stage in the construction. We show that events in different coordinate systems are connected by the appropriate finite and discrete version of the Lorentz transformation, that 3-momentum is conserved in events, and that this conservation law is the same as the requirement that different paths can ''interfere'' only when they differ by an integral number of deBroglie wavelengths. 38 refs., 12 figs., 3 tabs.
Date: October 5, 1988
Creator: Noyes, H.P. & McGoveran, D.O.
Partner: UNT Libraries Government Documents Department

SLAC R and D toward a TeV Linear Collider

Description: At CERN, KEK, Novosibirsk and SLAC, serious thought is being given to the design of linear colliders in the 0.5--2.0 TeV center-of-mass energy range. This paper reviews current progress at SLAC toward the design of such a collider. No attempt is made here to summarize ongoing work at the other laboratories. However, research on linear colliders is clearly an international effort, and success at SLAC will be greatly expedited by communication and cooperation with other laboratories in the US and abroad. In addition to major programs at the laboratories mentioned above, contributions relevant to linear collider design are being made at DESY, LAL (Orsay), LBL, LLNL and elsewhere. 49 refs., 6 tabs.
Date: October 1, 1988
Creator: Wilson, P.B.
Partner: UNT Libraries Government Documents Department

An essay on discrete foundations for physics

Description: We base our theory of physics and cosmology on the five principles of finiteness, discreteness, finite computability, absolute non-uniqueness, and strict construction. Our modeling methodology starts from the current practice of physics, constructs a self-consistent representation based on the ordering operator calculus and provides rules of correspondence that allow us to test the theory by experiment. We use program universe to construct a growing collection of bit strings whose initial portions (labels) provide the quantum numbers that are conserved in the events defined by the construction. The labels are followed by content strings which are used to construct event-based finite and discrete coordinates. On general grounds such a theory has a limiting velocity, and positions and velocities do not commute. We therefore reconcile quantum mechanics with relativity at an appropriately fundamental stage in the construction. We show that events in different coordinate systems are connected by the appropriate finite and discrete version of the Lorentz transformation, that 3-momentum is conserved in events, and that this conservation law is the same as the requirement that different paths can ''interfere'' only when they differ by an integral number of deBroglie wavelengths. 38 refs., 12 figs., 3 tabs.
Date: July 1, 1988
Creator: Noyes, H.P. & McGoveran, D.O.
Partner: UNT Libraries Government Documents Department

Results on semileptonic D and D/sub s/ decays and evidence for non-D/bar D/ decays of the /psi/ (3770)

Description: This paper discusses the following topics: Observation of Cabibbo suppressed semileptonic D decays; Search for D/sub s/ semileptonic decays; and Preliminary evidence for non-D/bar D/ decays of the /psi/ (3770). 4 refs., 3 figs., 2 tabs.
Date: December 1, 1988
Creator: Schindler, R.H.
Partner: UNT Libraries Government Documents Department

Wormholes and cosmology

Description: We review Coleman's wormhole mechanism for the vanishing of the cosmological constant. We find a discouraging result that wormholes much bigger than the Planck size are generated. We also consider the implications of the wormhole theory for cosmology. 7 refs., 2 figs.
Date: October 1, 1988
Creator: Klebanov, I. & Susskind, L.
Partner: UNT Libraries Government Documents Department

Prospects in B physics

Description: The status of B physics is reviewed with emphasis on the prospects for further developments, including the study of CP violating effects in the B mesons system. 29 refs., 13 figs.
Date: December 1, 1988
Creator: Gilman, F.J.
Partner: UNT Libraries Government Documents Department

Quantum beamstrahlung: Pulse shaping prospects for a photon-photon collider

Description: Beamstrahlung is the fraction energy loss to radiation as one beam pulse is accelerated by the electromagnetic field of the other pulse through which it passes in a collider. In linear colliders the individual pulses must be formed with much larger charge densities to compensate for their much lower rate of interactions (10/sup 2/ -- 10/sup 3/ per second) in comparison to storage rings (typically 10/sup 5/ per second). Therefore the electromagnetic fields generated by the charges in each pulse will be correspondingly larger, as will the acceleration they induce in the charges of the intersecting pulses; this in turn leads to a larger loss of energy to radiation. In this report we consider three questions: What is the quantum result for beamstrahlung and when is the classical result valid. How does the transverse beam geometry/emdash/i.e., ribbon versus cylindrical pulse/emdash/affect the beamstrahlung. Extending the quantum calculation to multiple photon emission, what is the photon flux and what are the prospects for a photon-photon collider. 3 refs., 2 figs.
Date: November 1, 1988
Creator: Blankenbecler, R. & Drell, S.D.
Partner: UNT Libraries Government Documents Department

Performance of the electronics for the Liquid Argon Calorimeter system of the SLC large detector

Description: Results of performance tests on electronics for the Liquid Argon Calorimeter (LAC) for the SLD experiment at SLAC are presented. The behavior of a sub-unit called a ''tophat,'' which processes 720 detector signals, is described. The electronics consists of charge sensitive preamplifiers, analog memories, A/D converters, and associated control and readout circuitry. An internal charge injection system is used to calibrate the overall response of the devices. Linearity is better than 1% of 0--28 pC charge at the input of the amplifiers. Noise (expressed as equivalent input charge) is less than 3000 electrons at a shaping time of 4 ..mu..s, with a slope of 2600 e/sup /minus///nF. Crosstalk to adjacent channels is less than 0.5%. The power consumption at a duty cycle of 13% is 61 W. 3 refs., 7 figs.
Date: October 1, 1988
Creator: Vella, E.; Abt, I.; Haller, G.M. & Honma, A.
Partner: UNT Libraries Government Documents Department

Polarization at SLC

Description: The SLAC Linear Collider has been designed to readily accommodate polarized electron beams. Considerable effort has been made to implement a polarized source, a spin rotation system, and a system to monitor the beam polarization. Nearly all major components have been fabricated. At the current time, several source and polarimeter components have been installed. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. It is expected that a beam polarization of 45% will be achieved with no loss in luminosity. 13 refs., 15 figs.
Date: July 1, 1988
Creator: Swartz, M.L.
Partner: UNT Libraries Government Documents Department

Recent results in strangeonium spectroscopy

Description: Data from exclusive s/bar s/ meson final states are shown. The data were obtained in a 4.1 ev/nb exposure of K/sup -/p interactions at 11 GeV/c in the LASS spectrometer at SLAC. The results from the analyses of these data is presented and the spectrum of strangeonium states is discussed. 8 refs., 8 figs.
Date: October 1, 1988
Creator: Aston, D.; Awaji, N.; Bienz, T.; Bird, F.; D'Amore, J.; Dunwoodie, W. et al.
Partner: UNT Libraries Government Documents Department

EGUN: An electron optics and gun design program

Description: The name EGUN has become commonly associated with the program also known as the SLAC Electron Trajectory Program. This document is an updated version of SLAC-226, published in 1979. The program itself has had substantial upgrading since then, but only a few new features are of much concern to the user. Most of the improvements are internal and are intended to improve speed or accuracy. EGUN is designed to compute trajectories of charged particles in electrostatic and magnetostatic fields, including the effects of space charge and self-magnetic fields. Starting options include Child's Law conditions on cathodes of various shapes, as well as used specified initial conditions. Either rectangular or cylindrical symmetry may be used. In the new jargon, the program is a 2-1/2 dimension code meaning 2-D in all fields and 3-D in all particle motion. A Poisson's Equation Solver is used to find the electrostatic fields by using difference equations derived from the boundary conditions. Magnetic fields are to be specified externally, by the user, by using one of several methods including data from another program or arbitrary configurations of coils. This edition of the documentation also covers the program EGN87c, which is a recently developed version of EGUN designed to be used on the newer models of personal computers, small main frames, work stations, etc. The EGN87c program uses the programming language C which is very transportable so the program should operate on any system that supports C. Plotting routines for most common PC monitors are included, and the capability to make hard copy plots on dot-matrix printer-plotters is provided. 18 refs., 7 figs.
Date: October 1, 1988
Creator: Herrmannsfeldt, W.B.
Partner: UNT Libraries Government Documents Department

Limits to the resolution of beam size measurement from fluorescent screens due to the thickness of the phosphor

Description: This paper discusses the use of fluorescent screens for the measurement of beam profiles on non-circulating particle beams. An expression for the intensity of the beam profile as a function of phosphor thickness is given. 3 refs., 8 figs.
Date: July 20, 1988
Creator: Johnson, C.D.
Partner: UNT Libraries Government Documents Department

The tau and beyond: Future research on heavy leptons

Description: This paper outlines directions for future experimental research on the tau and tau neutrino. Present limits on the existence of heavier charged leptons are reviewed, with emphasis on the close-mass lepton pair concept. 44 refs., 8 figs., 5 tabs.
Date: January 1, 1988
Creator: Perl, M.I.
Partner: UNT Libraries Government Documents Department

Future proton and electron colliders: Dreams for the 1990's

Description: In this paper I have reviewed the possibilities for new colliders that might be available in the 1990's. One or more new proton should be available in the late-90s based on plans of Europe, the US and the USSR. The two very high energy machines, LHC and SSC, are quite expensive, and their construction will be more decided by the politicians' view on the availability of resources than by the physicists' view of the need for new machines. Certainly something will be built, but the question is when. New electron colliders beyond LEP II could be available in the late 1990's as well. Most of the people who have looked at this problem believe that at a minimum three years of RandD are required before a proposal can be made, two years will be required to convince the authorities to go ahead, and five years will be required to build such a machine. Thus the earliest time a new electron collider at high energy could be available is around 1988. A strong international RandD program will be required to meet that schedule. In the field of B factories, PSI's proposal is the first serious step beyond the capabilities of CESR. There are other promising techniques but these need more RandD. The least RandD would be required for the asymmetric storage ring systems, while the most would be required for high luminosity linear colliders. For the next decade, high energy physics will be doing its work at the high energy frontier with Tevatron I and II, UNK, SLC, LEP I and II, and HERA. The opportunities for science presented by experiments at these facilities are very great, and it is to be hoped that the pressure for funding to construct the next generation facilities will not badly affect the operating budgets ...
Date: October 1, 1988
Creator: Richter, B.
Partner: UNT Libraries Government Documents Department

IEEE P1596, a scalable coherent interface for GigaByte/sec multiprocessor applications

Description: IEEE P1596, the Scalable Coherent Interface (formerly known as SuperBus) is based on experience gained during the development of Fastbus (IEEE 960), Futurebus (IEEE 896.1) and other modern 32-bit buses. SCI goals include a minimum bandwidth of 1 GByte/sec per processor; efficient support of a coherent distributed-cache image of shared memory; and support for segmentation, bus repeaters and general switched interconnections like Banyan, Omega, or full crossbar networks. To achieve these ambitious goals, SCI must sacrifice the immediate handshake characteristic of the present generation of buses in favor of a packet-like split-cycle protocol. Wire-ORs, broadcasts, and even ordinary passive bus structures are to be avoided. However, a lower performance (1 GByte/sec per backplane instead of per processor) implementation using a register insertion ring architecture on a passive ''backplane'' appears to be possible using the same interface as for the more costly switch networks. This paper presents a summary of current directions, and reports the status of the work in progress.
Date: November 1, 1988
Creator: Gustavson, D.B.
Partner: UNT Libraries Government Documents Department

Final focus supports for a TeV Linear Collider

Description: Final focus quadrupoles supported from structures in the endcap region of a physics experiment appear to meet the high-frequency vibration and stability criteria for a TeV Linear Collider (TLC). The support stays within a ten-degree cone, minimizing interference with the experimental apparatus. 3 refs., 3 figs.
Date: November 1, 1988
Creator: Ash, W.W.
Partner: UNT Libraries Government Documents Department

Summary of the electron accelerators session

Description: Since the last High Energy Physics Symposium, there has been considerable progress in the field of polarized electron accelerators. Projects well into construction include the SLC, HERA, and LEP. The status of polarized beams for these projects is discussed in this session. Semiclassical and quantum mechanical calculations of polarizing and depolarizing effects are discussed, for both linear colliders and for storage rings. Substantial progress is continuing in the understanding of depolarizing mechanisms for circular machines. Modelling of these machines is underway. Activities with polarized electron beams at Novosibirsk are described. 8 refs.
Date: October 1, 1988
Creator: Prescott, C.Y.
Partner: UNT Libraries Government Documents Department