61 Matching Results

Search Results

Advanced search parameters have been applied.

Inclusive large mass muon pair production in ultra-relativistic nucleus-nucleus collisions for colliding beams

Description: For colliding beams of several species of ions we compare thermal to perturbative quantum chromodynamic contributions for inclusive large mass muon pair production by using a hydrodynamic model to estimate the temperatures of the quark-gluon plasma produced by each species. The production of high energy dimuons with M {approx equal}-4 GeV, will be favored energetically by the quark-gluon plasma. 10 refs., 4 figs., 2 tabs.
Date: July 22, 1988
Creator: Roberts, L.E. (Lincoln Univ., PA (United States). Dept. of Physics Argonne National Lab., IL (United States). High Energy Physics Div. Institute for Scientific Studies, Wheaton, IL (United States))
Partner: UNT Libraries Government Documents Department

Some physics requirements for triggering in the intermediate tracking system of SDC

Description: I have investigated trigger requirements for the intermediate tracking system of the SDC detector, using muons in the final states of some physics processes of interest and relevance to the program envisaged to be pursued at the SSC. The study is done at the physics event generator level with the PYTHIA package, augmented by a very simplistic simulation of the momentum measurement expected from the intermediate tracking system. For the range in pseudorapidity of {vert bar}{eta}{vert bar} = 1.7--2.5, I find a subdivision into four basic bins sufficient to ensure that the width of the transverse momentum trigger threshold will not be dominated by the lack of knowledge of the polar angle. In addition, the azimuthal resolution has be better than 1 mrad to allow transverse momentum thresholds from p{sub t}{approx}10 GeV/c up to and beyond p{sub t}=20 GeV/c to be implemented which are needed to accomplish the physics goals. 10 figs., 1 tab.
Date: November 22, 1991
Creator: Trost, H.J.
Partner: UNT Libraries Government Documents Department

Muon/electron separation for atmospheric neutrino interactions

Description: A study has been made of the ability of the Soudan 2 nucleon decay detector to distinguish between showering and non-showering particles, utilizing several different pattern recognition techniques. This work has direct application in the determination of the {nu}{sub {mu}}/{nu}{sub e} ratio for atmospheric neutrino induced events. The results of the application of these techniques to Monte Carlo data and to calibration data from the ISIS test beam are presented.
Date: August 1, 1991
Creator: Allison, W.W.M.; Barr, G.D.; Brooks, C.B.; Cobb, J.H.; Kirby-Gallagher, L.M.; Giles, R.H. et al.
Partner: UNT Libraries Government Documents Department

Mechanical design and finite element analysis of the SDC central calorimeter

Description: When designing scintillating calorimeters for the study of particle interactions resulting from colliding beams, a primary goal is to instrument 100% of the available solid angle. In pursuit of this goal the challenge for mechanical designers is to minimize the amount of structural mass and still maintain acceptable engineering standards in the design. Argonne National Laboratory, High Energy Physics involvement in the design of a central calorimeter for the SSC started in 1989. Our first proposal was to design a depleted uranium scintillator calorimeter similar to the ZEUS detector presently installed at the HERA electron-proton collider in Hamburg, Germany. Argonne was involved at the time in final assembly of modules for ZEUS that had been designed and constructed at ANL. Due to the cost of using depleted uranium, lead was chosen as the absorber material. In collaboration with Westinghouse Science and Technology Center in Pittsburgh, Pennsylvania was embarked on a program to optimize the use of lead or lead alloys in the construction of the calorimeter. A cast lead design for the calorimeter evolved from this effort. Subsequent to this design, further pressure to reduce costs have now dictated a design which contains lead only in the electromagnetic sections of the calorimeter. The finite element analysis we will present here was done using lead for the HAD1 section of the barrel.
Date: January 1, 1992
Creator: Guarino, V.; Hill, N.F.; Nasiatka, J. (Argonne National Lab., IL (United States). High Energy Physics Div.); Hoecker, D.A.; Hordubay, T.D. Scherbarth, D.W. & Swensrud, R.L. (Westinghouse Electric Corp., Pittsburgh, PA (United States). Science and Technology Center)
Partner: UNT Libraries Government Documents Department

Multiple muon events in Soudan 2

Description: This is a progress report on multiple muon events recorded by the Soudan 2 detector. 6 refs.
Date: August 1, 1991
Creator: Allison, W.W.M.; Barr, G.D.; Brooks, C.B.; Cobb, J.H.; Kirby-Gallagher, L.M.; Giles, R.H. et al.
Partner: UNT Libraries Government Documents Department

Review of total cross sections and forward scattering parameters at ultra-high energies

Description: We review the field of the elastic scattering of pp and {bar p}p at the ultra-high energies. The recent total cross section, {sigma}{sub tot}, and {rho}-value results from the Fermilab Tevatron Collider experiments presented at the 4th Blois' Workshop on Elastic and Diffractive Scattering (Elba, Italy, in May, 1991), allow us a comprehensive overview of the field. 24 refs., 10 figs., 3 tabs.
Date: October 1, 1991
Creator: Block, M.M. (Northwestern Univ., Evanston, IL (United States). Dept. of Physics and Astronomy) & White, A.R. (Argonne National Lab., IL (United States). High Energy Physics Div.)
Partner: UNT Libraries Government Documents Department

On the massless gap'' adjustment of detected energy for passive material in front of a calorimeter

Description: I have designed a correction scheme for energy losses in passive material in front of a calorimeter based on the massless gap'' idea. I use a flexible geometry model of a calorimeter design for SDC outside of a solenoidal coil made of aluminium cylinders of adjustable thickness. The signal from the first radiation length of active calorimetry is scaled dependent on the incoming and observed energies of the shower. A reasonable recovery of the resolution of an unobstructed calorimeter is achieved using correction factors that depend only upon the total thickness of passive material. Thus a useful correction may be built into the hardware by increasing the amount of scintillator in the first radiation length of the active calorimeter. The distribution of correction factors determined event-by-event indicate that an additional dependence on the observed signal in the massless gap and total incident energy is clearly present.
Date: January 31, 1992
Creator: Trost, H.J.
Partner: UNT Libraries Government Documents Department

On the scattering of atmospheric muons in the rock above Soudan 2

Description: I have investigated the effect of scattering in the rock overburden on the position and direction of atmospheric muons as observed at the Soudan 2 detector relative to the surface. The dominant contributions to the fluctuations in those observables arise from multiple Coulomb scattering and delta ray production. The contribution of the other energy loss mechanisms, bremsstrahlung, pair production and nuclear interactions, is small, with slowly increasing importance at very large deviations from the means of the distributions.
Date: January 24, 1992
Creator: Trost, H.J.
Partner: UNT Libraries Government Documents Department

Chiral symmetry breaking in gauge theories from Reggeon diagram analysis

Description: It is argued that reggeon diagrams can be used to study dynamical properties of gauge theories containing a large number of massless fermions. SU(2) gauge theory is studied in detail and it is argued that there is a high energy solution which is analogous to the solution of the massless Schwinger model. A generalized winding-number condensate produces the massless pseudoscalar spectrum associated with chiral symmetry breaking and a trivial'' S-Matrix.
Date: December 16, 1991
Creator: White, A.R.
Partner: UNT Libraries Government Documents Department

Composition studies based on coincident air shower array and underground muon data

Description: We report on a final analysis of coincident underground muon data measured by the Soudan 1 proton decay detector and air shower data measured by an associated proportional tube array. These data were reported first at the 21st ICRC, Adelaide. We have done further analysis to determine the principal sources of systematic errors in such measurements, including different models of the primary interaction.
Date: August 1, 1991
Creator: DasGupta, U.; Ruddick, K. (Minnesota Univ., Minneapolis, MN (United States)) & Fields, T.H. (Argonne National Lab., IL (United States))
Partner: UNT Libraries Government Documents Department

A beam profile monitor for small electron beams

Description: Measurement of beam properties at the foci of high energy linacs is difficult due to the small size of the waists in proposed and existing accelerators (1 nm {minus} 2 {mu}). This paper considers the use of bremsstrahlung radiation from thin foils to measure the size and phase space density these beams using nonimaging optics. The components of the system are described, and the ultimate resolution, evaluated theoretically for the case of the Final Focus Test Beam at Stanford Linear Accelerator Center, is a few nm. 13 refs., 4 figs. 1 tab.
Date: January 23, 1991
Creator: Norem, J.
Partner: UNT Libraries Government Documents Department

Design considerations for a scintillating plate calorimeter for SDC

Description: As scintillating plate calorimetry is a viable option for the SDC detector, it is imperative that the phase space of passive and active materials be explored in a systematic fashion. To this end, we have examined several different configurations of passive and active materials as a function of incident energy, to see what the resolution and e/h characteristics are of each of these configurations. These studies have been carried out using the CALOR89 Monte Carlo simulation package. 3 figs., 5 tabs.
Date: July 26, 1991
Creator: Handler, T. (Tennessee Univ., Knoxville, TN (United States). Dept. of Physics); Job, P.K. (Argonne National Lab., IL (United States). High Energy Physics Div.) & Gabriel, T.A. (Oak Ridge National Lab., TN (United States))
Partner: UNT Libraries Government Documents Department

Construction of. Delta. m sup 2 --sin sup 2 2. theta. plots

Description: In the two-flavor approximation, the probability for a neutrino to oscillate from one flavor to the other is given by {Rho}{sub {nu}a}{yields}{sub {nu}b} = sin{sup 2} 2{theta} sin{sup 2} (1.27 {Delta}m{sup 2} L/E{sub {nu}}) where {theta} is the mixing angle, {Delta}m{sup 2} = {vert bar}m{sub {nu}a}{sup 2} {minus} m{sub {nu}b}{sup 2}{vert bar} is measured in (eV/c{sup 2}){sup 2}, L, the distance from the source, is measured in km, and E, the beam energy, is measured in GeV. If either {Delta}m{sup 2} or sin{sup 2} 2{Theta} is zero, there is no oscillation. They might also have small, non-zero values, causing the oscillations to be so small as to be unobservable in a particular experiment. They may also have values which allow us to determine the probability of oscillation, but so far no compelling evidence for oscillation exists. The universal method of portraying what region of parameter space is explored by a neutrino oscillation experiment is to mark off an area on a {Delta}m{sup 2} vs. sin{sup 2} 2{theta} plot. Typically, a line is graphed, with the claim that if the experiment finds not evidence of oscillation, one can, for example, be 90% certain that {Delta}m{sup 2} and sin{sup 2} 2{theta} lie within the region below and to the left of the line. Since these plots are so widely used, it is useful to understand the process by which they are created.
Date: January 1, 1991
Creator: Snyder, R. (Oberlin Coll., OH (United States). Dept. of Physics) & Goodman, M. (Argonne National Lab., IL (United States))
Partner: UNT Libraries Government Documents Department

Development of a custom monolithic device for data acquisition from a scintillating calorimeter at the superconducting super collider

Description: A clock-driven continuous sequential write/random read data acquisition architecture for a scintillating calorimeter at the SSC is presented. Simplicity of design and operation as well as potentially dead time-less operation are the motivations of this effort. The architecture minimizes the number of fast control signals, thereby reducing pickup from digital control lines by sensitive analog circuits in the front-end device. This architecture also reduces the logic necessary on the front-end device improving reliability and easing design and operation. Operation and design of the front-end device are discussed. 3 refs., 7 figs.
Date: January 1, 1991
Creator: Ekenberg, T.; Dawson, J.W.; Talaga, R.L.; Stevens, A.E. & Haberichter, W.N.
Partner: UNT Libraries Government Documents Department

The effect of passive material on the detection of hadrons in calorimeter configurations for the SDC detector

Description: We have used a flexible geometry model of a calorimeter design for SDC to study the effect of passive material in front of the calorimeter and between the barrel and endcap modules on the apparent response to hadrons. The thicknesses of the passive materials have been chosen to closely resemble the currently projected wall thicknesses of the scintillating tile-fiber and liquid-argon calorimeter designs. The liquid-argon model contains about three times the amount of material in its shells compared to the tile-fiber model. The solenoid coil reduces the relative difference somewhat in the barrel region but constitutes only a minor correction in the transition region from barrel to endcap. Correspondingly, we find a significantly worse response for the liquid-argon case which we demonstrate using beams of single {pi}{sup minus} particles of 10 GeV/c momentum. 13 refs., 6 figs.
Date: August 14, 1991
Creator: Kirk, T.B.W. & Trost, H.J.
Partner: UNT Libraries Government Documents Department

Underground muons from the direction of Cygnus X-3 during the January 1991 radio flare

Description: Muons recorded in the Soudan 2 underground nucleon decay detector from January 1989 to February 1991 have been examined for any correlation with the radio flares of Cyguns X-3 observed during this period. On two nearby days during the radio flare of January 1991 a total of 32 muons within 2.0{degrees} of the Cyguns X-3 direction were observed when 11.4 were expected.
Date: August 1, 1991
Partner: UNT Libraries Government Documents Department

A first simulation study of the barrel-endcap transition region in a calorimeter of the scintillator tile design

Description: We have made a first study of the calorimetric response to 10 GeV/c charged pions in the transition region between barrel and endcap for the scintillator-tile design pursued at Argonne National Laboratory using the simulation program ANLSIM. For (very nearly) projective tower orientations in the barrel, the crack appears deep within a narrow angular range, causing a loss of the response in that region up to 40%. Pointing the towers onto the beam axis 35 cm or more away from the nominal-interaction point leads to a shortened depth of the barrel-endcap crack as seen by particles incident from the interaction region, cutting the maximum loss down by almost one half. The worsening of the resolution follows the same trend. Introduction of a solenoidal coil in front of the calorimeter causes an overall degradation of the response by an amount nearly comparable to the effect of the crack. Electrons of the same incident momentum are more strongly affected by the coil than pions but see only a much narrower region of degradation by the crack. 15 refs., 6 figs., 2 tabs.
Date: August 24, 1990
Creator: Proudfoot, J. & Trost, H.J.
Partner: UNT Libraries Government Documents Department

Underground muons observed in the Soudan 2 detector from the directions of x-ray sources

Description: We report on observations of underground muons made with the Soudan 2 proton decay detector at a depth of 2090 mwe from the directions of the binaries Hercules X-1 and 1E2259+586 and the Crab pulsar.
Date: August 1, 1991
Creator: Allison, W.W.M.; Barr, G.D.; Brooks, C.B.; Cobb, J.H.; Giles, R.H.; Perkins, D.H. et al.
Partner: UNT Libraries Government Documents Department

Calculations of bottom quark production at hadron colliders

Description: This thesis studies Monte Carlo simulations of QCD heavy flavor production processes (p{bar p} {yields} Q({anti Q})X) at hadron colliders. ISAJET bottom quark cross-sections are compared to the O({alpha} {sub s}{sup 3}) perturbative calculation of Nason, Dawson, and Ellis. These Monte Carlo cross-sections are computed from data samples which use different parton distribution functions and physics parameters. Distributions are presented in the heavy quark's transverse momentum and rapidity. Correlations in rapidity and azimuthal angle are computed for the heavy flavor pair. Theory issues which arise are the behavior of the cross-section at low and high values of transverse momentum and the treatment of double counting problems in the flavor excitation samples. An important result is that ISAJET overestimates bottom quark production cross-sections and K factors. These findings are relevant for estimates of rates and backgrounds of heavy floor events.
Date: June 29, 1991
Creator: Kuebel, D.
Partner: UNT Libraries Government Documents Department

Shower counter resolution scaling

Description: The EM shower counter for the SDC detector has a resolution expression containing two stochastic terms plus a constant term. Recent measurements clarifying the sources of these terms are presented here. 3 refs., 4 figs.
Date: October 14, 1991
Creator: Kirk, T.B.W.
Partner: UNT Libraries Government Documents Department

Simultaneous observations of extensive air showers and underground muons at Soudan 2

Description: We have built a small proportional tube air shower array on the surface above the Soudan 2 proton decay detector in Soudan, Minnesota, USA. This array, in coincidence with the underground detector, allows simultaneous surface and underground observations of high energy cosmic ray showers. These observations, still in their initial stages, may eventually be able to provide information about the composition of cosmic ray primaries in the knee'' region of the energy spectrum. 4 refs.
Date: August 1, 1991
Creator: Allison, W.W.M.; Barr, G.D.; Brooks, C.B.; Cobb, J.H.; Giles, R.H.; Perkins, D.H. et al.
Partner: UNT Libraries Government Documents Department

Z yields jets+. gamma. as a signal for R-parity violation

Description: Supersymmetric models with explicit R-parity violation can induce new rare decay modes of the Z boson into single supersymmetric particles. Here, the rate and signature for one such decay, Z {yields} {tilde {upsilon}} {gamma}, is examined, where it is found that the rate is at least an order of magnitude smaller than that for the process Z{yields} H{gamma}, even with larger values of the R-parity violating couplings.
Date: February 1, 1992
Creator: Hewett, J.L.
Partner: UNT Libraries Government Documents Department

High Energy Physics Division semiannual report of research activities, July 1, 1991--December 31, 1991

Description: This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period of July 1, 1991--December 31, 1991. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. Lists of division publications and colloquia are included.
Date: April 1, 1992
Creator: Schoessow, P.; Moonier, P.; Talaga, R. & Wagner, R. (eds.)
Partner: UNT Libraries Government Documents Department