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B/sup 0/-anti B/sup 0/ mixing: A theoretical evaluation after ARGUS

Description: After an introduction into the phenomenology of B/sup 0/ -anti B/sup 0/ mixing is given, a rather detailed is presented on the theoretical concepts that are involved. An attempt is made to elucidate the discrepancy between different theoretical claims. CP violtion is touched only very briefly.
Date: January 1, 1988
Creator: Bigi, I.
Partner: UNT Libraries Government Documents Department

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

Basic optics of the SLC (Stanford Linear Collider) Final Focus System

Description: In this report we discuss some general optics principles and scaling laws that have been useful in guiding the design and operation of the Final Focus System for the Stanford Linear Collider. Included are expressions for the minimum {Beta}{sub x}* and {Beta}{sub y}* that can be expected for the present SLC design at the interaction point as a function of beam emittance. 6 refs., 13 figs.
Date: December 1, 1988
Creator: Brown, K.L.
Partner: UNT Libraries Government Documents Department

Institutional Plan, FY1989--FY1994

Description: This report discusses future plans of the Stanford Linear Accelerator Center. Topics covered are: Laboratory Mission; Special Issues; Laboratory Strategic View; Scientific Program at SLAC; Initiatives; Education and Technology Transfer Programs; Site and Facilities; and Resource Projections. 9 tabs.
Date: December 1, 1988
Creator: Available, Not
Partner: UNT Libraries Government Documents Department

Measurement of the B hadron lifetime from Mark II at PEP

Description: Using data taken by the Mark II detector at PEP, the decays of B hadrons are tagged by identifying leptons at high transverse momentum. By means of a precision inner drift chamber, the impact parameters of these leptons are measured with respect to the B production point. From this impact parameter distribution, the B hadron lifetime is found to be 0.98 +- 0.12 +- 0.13 ps. This measurement can be used to place constraints models of quark mixing. 11 refs., 2 figs., 2 tabs.
Date: January 1, 1988
Creator: Ong, R.A.
Partner: UNT Libraries Government Documents Department

Thoughts on software and computing

Description: This talk has three distinct parts. The first two parts are on vector and parallel processing and their success, or lack thereof for HEP. The third part is an analysis on the software situation in HEP. These topics have been chosen because of the frequency with which they are discussed in the hallways of our laboratories and institutions. This review looks at the field from a particular point of view: that of an experimental physicist working with a large detector at a collider and, in addition, only considers the offline processing aspects of the field. 7 refs., 7 figs.
Date: March 1, 1988
Creator: Kunz, P.F.
Partner: UNT Libraries Government Documents Department

Proceedings of the international workshop on next-generation linear colliders

Description: This report contains papers on the next-generation of linear colliders. The particular areas of discussion are: parameters; beam dynamics and wakefields; damping rings and sources; rf power sources; accelerator structures; instrumentation; final focus; and review of beam-beam interaction.
Date: December 1, 1988
Creator: Riordan, M. (ed.)
Partner: UNT Libraries Government Documents Department

Induction linac drivers for heavy ion fusion

Description: The Heavy Ion Fusion Accelerator Research (HIFAR) program of the USDOE has for several years concentrated on developing linear induction accelerators as Inertial Fusion (IF) drivers. This accelerator technology is suitable for the IF application because it is readily capable of accelerating short, intense pulses of charged particles with good electrical efficiency. The principal technical difficulty is in injecting and transporting the intense pulses while maintaining the necessary beam quality. The approach used has been to design a system of multiple beams so that not all of the charge has to be confined in a single beam line. The beams are finally brought together in a common focus at the target. This paper will briefly present the status and future plans of the program, and will also briefly review systems study results for HIF. 2 refs., 5 figs.
Date: September 1, 1988
Creator: Herrmannsfeldt, W.B. & Keefe, D.
Partner: UNT Libraries Government Documents Department

A CDU-based data acquisition system for the energy spectrometer at the Stanford Linear Collider

Description: We describe a system using the Calorimetry Data Unit (a 32-channel multisample analog integrated circuit) to read out the charge ejected by secondary emission of a synchrotron beam from wires lying in its path. The wires comprise the Wire-Imaging Synchrotron Radiation Detector (WISRD) in the SLC Extraction-Line Spectrometer. The primary module in the system is a board containing 24 channels of charge sensitive amplification, shaping, sampling, multiplexing and digitization. This board also provides a fast analog measure of the charge distribution across the wires. We discuss the design and performance of this system. 4 refs., 5 figs.
Date: October 1, 1988
Creator: Briggs, D.D.; Tinsman, J.E.; Rouse, F. & von Zanthier, C.
Partner: UNT Libraries Government Documents Department

Introduction to human factors

Description: Some background is given on the field of human factors. The nature of problems with current human/computer interfaces is discussed, some costs are identified, ideal attributes of graceful system interfaces are outlined, and some reasons are indicated why it's not easy to fix the problems. (LEW)
Date: March 1, 1988
Creator: Winters, J.M.
Partner: UNT Libraries Government Documents Department

Electron ray tracing programs for gun design and beam transport. [None]

Description: Computer simulation of electron and ion sources is made by using a class of computer codes known as gun design programs. In this paper, we shall first list most of the necessary and some optional capabilities of such programs. Then we will briefly note specific codes and/or authors of codes with attention to specialized applications if any. There may be many more such programs in use than are treated here; we are only trying to cover a range of examples, not perform a comprehensive survey.
Date: May 1, 1988
Creator: Herrmannsfeldt, W.B.
Partner: UNT Libraries Government Documents Department

Electron-positron physics at 1 TeV

Description: We discuss the motivation for TeV e/sup +/ e/sup )minus/) linear colliders, some aspects of their design, and the experimental consequences that follow from the design. After a brief discussion of the general physics environment, we consider the discovery potential of these colliders by examining three sample processes: the detection of new heavy leptons, standard Higgs bosons, and charged Higgs bosons. 13 refs., 22 figs., 5 tabs.
Date: March 1, 1988
Creator: Feldman, G.J.
Partner: UNT Libraries Government Documents Department

Recent results on open and hidden charm production in e/sup +/e/sup -/ annihilation at 29 GeV

Description: Inclusive )psi) production in e/sup +/e/sup )minus/) annihilation at 29 GeV has been measured with the Mark II detector. The )psi) cross section is found to be 1.1 )+-) 0.5 )+-) 0.4 pb. An upper limit of 0.02 sigma/sub ..mu mu../ is obtained for other sources of )psi) production. )eta) production has also been investigated, using the ..gamma gamma.. decay mode. The )eta) fragmentation function has been measured and found to be in good agreement with the Lund model prediction. )eta)' production has been measured for the first time in high energy e/sup +/e/sup )minus/) annihilation. A search for D/sub s//sup )+-/) decays into )eta) ..pi../sup )+-/) and )eta)' ..pi../sup )+-/) has been performed and evidence has been found for both decay modes at the 3 sigma level. 11 refs., 5 figs.
Date: March 1, 1988
Creator: Wormser, G.
Partner: UNT Libraries Government Documents Department

Prospects for physics at e/sup +/e/sup -/ linear colliders

Description: The present thinking on high-energy e/sup /plus//e/sup /minus// linear colliders is reviewed, stressing those points that have consequences for detector design and physics analyses. Detector requirements are discussed. Experimental aspects of the physics that can be done at these colliders are discussed: first the general physics environment, then a standard process, W/sup /plus// W/sup /minus// detection, and finally four examples of the discovery potential of these colliders /emdash/ heavy quarks, heavy leptons, standard Higgs bosons, and charged Higgs bosons. The conclusions of this study will be stated. 23 refs., 40 figs.
Date: March 1, 1988
Creator: Feldman, G.J.
Partner: UNT Libraries Government Documents Department

Breakdown phenomena in high power klystrons

Description: In the course of developing new high peak power klystrons at SLAC, high electric fields in several regions of these devices have become an important source of vacuum breakdown phenomena. In addition, a renewed interest in breakdown phenomena for nanosecond pulse, multi-megavolt per centimeter fields has been sparked by recent R and D work in the area of gigawatt RF sources. The most important regions of electrical breakdown are in the output cavity gap area, the RF ceramic windows, and the gun ceramic insulator. The details of the observed breakdown in these regions, experiments performed to understand the phenomena and solutions found to alleviate the problems will be discussed. Recently experiments have been performed on a new prototype R and D klystron. Peak electric fields across the output cavity gaps of this klystron exceed 2 MV/cm. The effect of peak field duration (i.e. pulse width) on the onset of breakdown have been measured. The pulse widths varied from tens of nanoseconds to microseconds. Results from these experiments will be presented. The failure of ceramic RF windows due to multipactor and puncturing was an important problem to overcome in order that our high power klystrons would have a useful life expectancy. Consequently many studies and tests were made to understand and alleviate window breakdown phenomena. Some of the results in this area, especially the effects of surface coatings, window materials and processing techniques and their effects on breakdown will be discussed. Another important source of klystron failure in the recent past at SLAC has been the puncturing of the high voltage ceramic insulator in the gun region. A way of alleviating this problem has been found although the actual cause of the puncturing is not yet clear. The ''practical'' solution to this breakdown process will be described and a possible mechanism ...
Date: March 1, 1988
Creator: Vlieks, A.E.; Allen, M.A.; Callin, R.S.; Fowkes, W.R.; Hoyt, E.W.; Lebacqz, J.V. et al.
Partner: UNT Libraries Government Documents Department

Landau damping in the improved SLC linac: A, The sensitivity to injection jitter

Description: In this report we study the effects of injection jitter on emittance growth, and hence on luminosity, in the improved linac with stronger focusing, and for the new bunch parameters. We consider both cases when Landau damping has been invoked, and when it has not been.
Date: April 1, 1988
Creator: Bane, K.L.F.
Partner: UNT Libraries Government Documents Department

A study of low Q/sup 2/ radiative Bhabha scattering

Description: This thesis presents a study of electron-positron scattering, via nearly real photon exchange, where in the process one or more high energy photons are produced. The motivations behind the work are twofold. Firstly, the study is a sensitive test of the theory of electron-photon interactions, quantum electrodynamics. A deviation from the theory could indicate that the electron is a composite particle. Secondly, a thorough understanding of this process is necessary for experiments to be done in the near future at the Stanford Linear Collider and the LEP facility at CERN. Calculations for the process to third and fourth order in pertubation theory are described. Methods for simulating the process by a Monte Carlo event generator are given. Results from the calculations are compared to data from the Mark II experiment at the PEP storage ring. The ratio of measured to calculated cross sections are 0.993 /+-/ 0.017 /+-/ 0.015 and 0.99 /+-/ 0.16 /+-/ 0.08 for final states with one and two observed photons respectively, where the first errors are statistical and the second systematic. The excellent agreement verifies the calculations of the fourth order radiative correction. No evidence for electron substructure is observed.
Date: March 1, 1988
Creator: Karlen, D.A.
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

Canonical description of a second-order achromat

Description: Charged particle motion in second-order magnetic optical achromat is described using a canonical perturbation theory. Necessary and sufficient conditions for the existence of such a device are presented. Given these conditions, the second-order matrix elements at the end of the achromat are found explicity. It is shown that all geometric matrix elements are equal to zero and all chromatic matrix elements are either also equal to zero or proportional to the corresponding chromaticity. Thus all second-order matrix elements vanish simultaneously when the two chromaticities are made to be equal to zero 13 refs., 1 tab.
Date: March 1, 1988
Creator: Kheifets, S.A.; Fieguth, T.H. & Ruth, R.D.
Partner: UNT Libraries Government Documents Department

Strings in four dimensions

Description: We review the construction and properties of four dimensional string models, using free fermions on the world-sheet. We prove that as opposed to gauge symmetries, broken space-time supersymmetry can only be restored continuously by decompactification. 40 refs.
Date: January 1, 1988
Creator: Bachas, C.P.
Partner: UNT Libraries Government Documents Department

Multi-bunch energy compensation

Description: To obtain a luminosity of 10{sup 34} cm{sup {minus}2} sec{sup {minus}1} in a TeV Linear Collider (TLC), it will probably be necessary to accelerate many bunches in one filling of the rf structure. This has the effect of extracting more energy from the structure and thus enhances the overall efficiency of the accelerator. However, this leads to many problems. First, the train bunches is subject to cummulative beam breakup transversely. This can be controlled by damping the transverse modes with slots in the irises coupled to waveguides. In addition, the energy of the bunches must be kept the same to high precision. For the fundamental mode, this entails adjusting the timing of the rf fill and also the bunch spacing. The higher longitudinal modes, although they do not induce instability, also may lead to bunch-to-bunch variations in energy. However, it also seems possible to damp these modes to cure this problem. Of course, there are also problems associated with damping a train of bunches in a damping ring. In this paper we discuss some of the issues of multi-bunch energy compensation. In the first two sections, we review some basics about energy extraction by a single bunch, and then, multi-bunch energy compensation is treated. We discuss various tolerance issues associated with deviations of amplitude and phase of the rf away from the ideal.
Date: February 1, 1988
Creator: Ruth, R.D.
Partner: UNT Libraries Government Documents Department

Relativistic klystron research for high gradient accelerators

Description: Relativistic klystrons are being developed as a power source for high gradient accelerator applications which include large linear electron--positron colliders, compact accelerators, and FEL sources. We have attained 200MW peak power at 11.4 GHz from a relativistic klystron, and 140 MV/m longitudinal gradient in a short 11.4 GHz accelerator section. We report here on the design of our first klystrons, the results of our experiments so far, and some of our plans for the near future. 5 refs., 7 figs.
Date: June 1, 1988
Creator: Allen, M.A.; Callin, R.S.; Deruyter, H.; Eppley, K.R.; Fowkes, W.R.; Herrmannsfeldt, W.B. et al.
Partner: UNT Libraries Government Documents Department