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Soudan nucleon decay program

Description: The Soudan nucleon decay program is being carried out in the Soudan iron mine in northeastern Minnesota, at a depth of 2000 m of water equivalent. A 30-ton prototype experiment, Soudan 1, has been built and is now being operated by a University of Minnesota - Argonne National Laboratory collaboration. The detector is a block of iron-loaded concrete instrumented with 3456 gas proportional tubes. It can detect nucleon decay at the 2 x 10/sup 30/ year level, and will measure cosmic-ray induced backgrounds. Soudan 1 is also obtaining data on very high energy cosmic-ray interactions. Monte-Carlo predictions of performance have been checked by calibration of a detector module in a charged-particle test beam. A proposal to build a 1000-ton experiment, Soudan 2, has been submitted to funding agencies in the USA and the UK by a Minnesota - Argonne - Oxford University collaboration. The proposed detector utilizes drift chambers with 50-cm drifts to obtain very fine-grained ionization and tracking information at low cost. This tracking-calorimeter detector has a fiducial mass of 650 tons, and could be operating in 1985. A drifting scheme utilizing 50 cm x 5 m x 1 cm planar chambers has been shown feasible, and prototypes of alternate drifting structures are also being studied. A plan to provide expandability to an eventual 5000 tons has been developed.
Date: January 1, 1981
Creator: Ayres, D.S.
Partner: UNT Libraries Government Documents Department

New evidence from Soudan 1 for underground muons associated with Cygnus X-3

Description: The Soudan 1 experiment has obtained additional evidence for underground muons associated with the x-ray pulsar Cygnus X-3. We report the preliminary analysis of data recorded during the October 1985 radio outburst of Cygnus X-3, which show a significant excess of muons for a narrow range of Cygnus X-3 phases.
Date: June 5, 1986
Creator: Ayres, D.S.
Partner: UNT Libraries Government Documents Department

Evidence from the Soudan 1 experiment for underground muons associated with Cygnus X-3

Description: The Soudan 1 experiment has yielded evidence for an average underground muon flux of approx.7 x 10/sup -11/ cm/sup -2/ s/sup -1/ which points back to the x-ray binary Cygnus X-3, and which exhibits the 4.8 h periodicity observed for other radiation from this source. Underground muon events which seem to be associated with Cygnus X-3 also show evidence for longer time variability of the flux. Such underground muons cannot be explained by conventional models of the propagation and interaction of cosmic rays. 16 refs., 5 figs., 1 tab.
Date: September 1, 1985
Creator: Ayres, D.S.
Partner: UNT Libraries Government Documents Department

Planning for the next generation of proton-decay experiments in the United States

Description: There are now three well-developed proposals for new proton decay detectors to be built in the United States. These are the 1000 to 5000-ton Soudan 2 tracking calorimeter, the 1400-ton Homestake II liquid scintillator Tracking Spectrometer, and the 2500-ton University of Pennsylvania liquid-scintillator - proportional-drift-cell calorimeter. These proposals were reviewed by the Department of Energy Technical Assessment Panel on Proton Decay in February 1982. I shall describe the Soudan and Pennsylvania proposals, present the latest results from the 31-ton Soudan 1 experiment, and discuss the recommendations of the DOE Panel. Following these recommendations, a one-week workshop, to be held at Argonne in June, will focus on the optimization of techniques for future experiments.
Date: January 1, 1982
Creator: Ayres, D.S.
Partner: UNT Libraries Government Documents Department

Initial data from the Soudan 2 experiment

Description: Soudan 2 is an 1100-ton tracking calorimeter which is being built 713 m underground to search for nucleon decay and to study neutrino and cosmic-ray physics. The detector is assembled from 256 identical 4.3-ton calorimeter modules. Each module consists of finely segmented iron and drift tubes, and records three space coordinates and dE/dx for every tube crossing. It is surrounded on all sides by a 1700 m{sup 2} active shield of proportional tubes. The first atmospheric neutrino interactions and a magnetic monopole search are described. Prospects for cosmic ray studies are summarized.
Date: October 12, 1990
Creator: Ayres, D.S.
Partner: UNT Libraries Government Documents Department

The MINOS long-baseline experiment at Fermilab.

Description: The MINOS long-baseline experiment will search for neutrino oscillations by measuring an intense {nu}{sub {mu}} beam at the end of a 730 km flight path. The 10,000 ton MINOS far detector will utilize magnetized steel plates interleaved with track chambers to reconstruct event topologies and to measure the energies of the muons, hadrons and electromagnetic showers produced by neutrino interactions. The experiment is designed to detect {nu}{sub {mu}} {r_arrow} {nu}{sub {tau}} and {nu}{sub {mu}} {r_arrow} {nu}{sub e} oscillations with {Delta}m{sup 2} {ge} 0.001 eV{sup 2} and sin{sup 2}(2{theta}) {ge} 0.01. Any oscillation signal observed can be verified and studied by several independent tests: a near/far rate comparison, the NC/CC event ratio, the CC and NC event energy spectra, and the identification of electrons and {tau} leptons. The neutrino beam can be operated in both wide-band and narrow-band configurations, allowing the detailed study oscillation phenomena. The experiment is scheduled to begin operation in 2001.
Date: October 15, 1997
Creator: Ayres, D. S.
Partner: UNT Libraries Government Documents Department

Electrodeless drift chambers with 50-cm drift distance

Description: The electrodeless drift-chamber technique is potentially very useful in applications requiring the drifting of ionization in gas over long distances in narrow channels. Chamber construction is simple and cheap; the technique is well suited to very large detectors operating in low-rate environments. Prototype tests on planar chambers reveal excellent drifting characteristics after the initial charging, but show a substantial degradation of pulse height from cosmic rays over a two-week period. The loss of efficiency appears to be caused by excess charge buildup on the dielectric surfaces of the chamber. Several solutions are suggested.
Date: August 1, 1982
Creator: Ayres, D.S. & Price, L.E.
Partner: UNT Libraries Government Documents Department

A combined cosmic ray muon spectrometer and high energy air shower array

Description: Cosmic rays have been detected at energies in excess of 10/sup 20/ eV, and individual sources have been conclusively identified as intense emitters of gamma rays at energies up to 10/sup 16/ eV. There is clearly a great deal of exciting astrophysics to be learned from such studies, but it has been suggested that there may be particle physics to be learned from the cosmic beam as well. Based in particular on the reports of surprisingly high fluxes of underground muons from the direction of Cygnus X-3 modulated by the known orbital period, there have been several suggestions recently invoking stable supersymmetric particles produced at Cygnus X-3, enhanced muon production from high energy photons, quark matter, and ''cygnets.'' Although the underground muon results have been questioned, it may still be worthwhile to consider the possibility of new physics beyond the standard model with energy scale (G/sub F/)/sup -1/2/ greater than or equal to 0.25 TeV. For example, there have been recent discussions on the experimental signatures to be observed from new high energy photon couplings to matter, exchanges between constituent quarks and leptons, and stable gluinos and photinos mixed in with the cosmic gamma ray flux. We describe here a possible detector to search for such effects. We utilize the possibility that point sources like Cygnus X-3 can be used to provide a directional time-modulated ''tagged'' high energy photon beam.
Date: January 1, 1986
Creator: Cherry, M.L.; Ayres, D.S. & Halzen, F.
Partner: UNT Libraries Government Documents Department

Detectors for the MINOS long-baseline neutrino oscillation experiment

Description: The MINOS long-baseline experiment will use an intense neutrino beam, generated by Fermilab`s Main Injector accelerator, and 730 km flight path to search for neutrino oscillations. The 10,000 ton MINOS far detector will utilize toroidally magnetized steel plates interleaved with track chambers to reconstruct event topologies and to measure the energies of the muons, hadrons and electromagnetic showers produced by neutrino interactions. The MINOS collaboration is currently developing three alternative technologies for the track chambers: `Iarocci` tubes (operated in either limited streamer or saturated proportional mode), RPC`s (with either glass or ABS plates), and scintillator (either liquid or plastic) with wavelength shifting fiber readout. The technology choice will be made in mid 1997 based on the projected performance and cost of the 32,000 m{sup 2} active detector system.
Date: December 31, 1996
Creator: Ayres, D.S.
Partner: UNT Libraries Government Documents Department

The soudan 2 experiment

Description: Soudan 2 is an 1100-ton tracking calorimeter which is being constructed to search for nucleon decay. The detector consists of finely segmented iron instrumented with drift tubes, and records three spatial coordinates and dE/dx for every gas crossing. Excellent event-reconstruction capability, particle identification, and muon sign and direction determination give superior rejection of the neutrino background to nucleon decay in many modes. The first 275 tons of Soudan 2 is operating and a charged-particle test beam calibration is under way. Construction is scheduled for completion in 1992. 4 refs., 6 figs., 2 tabs.
Date: May 25, 1989
Creator: Ayres, D.S.
Partner: UNT Libraries Government Documents Department

Observation of f-f' interference in $pi$$sup -$p $Yields$ K$sup -$K$sup +$n at 6 GeV/c

Description: Preliminary results from a study of $pi$$sup -$p $Yields$ K$sup -$K$sup +$n at 6 GeV/c with the Argonne Effective Mass Spectrometer are presented. The 100,000-event data sample shows a dramatic drop in the Y$sub 4$$sup 0$ moment of the K$sup -$K$sup +$ decay angular distribution at a K$sup -$K$sup +$ mass of 1500 MeV. This feature is interpreted as a result of f-f' interference, which can also explain the excess of D-wave cross section near 1450 MeV observed previously. (auth)
Date: January 1, 1975
Creator: Pawlicki, A.J.; Ayres, D.S.; Diebold, R.; Kramer, S.L. & Wicklund, A.B.
Partner: UNT Libraries Government Documents Department

Amplitude analysis of the K/sup -/K/sup +/ system produced in the reactions. pi. /sup -/p. -->. K/sup -/K/sup +/N and. pi. /sup +/N. -->. K/sup -/K/sup +/p at 6 GeV/c. [S'(1300)]

Description: An amplitude analysis of the K/sup -/K/sup +/ system produced in the reactions ..pi../sup -/p ..-->.. K/sup -/K/sup +/n and ..pi../sup +/n ..-->.. K/sup -/K/sup +/p was carried out using data from a high statistics experiment carried out with the Argonne Effective Mass Spectrometer. Combining the results from the two reactions allows the separation of the KantiK production amplitudes into their isospin-zero and one components. An enhancement is deserved in the S-wave amplitude near 1300 MeV which we call the S'. Using various physical arguments, including the t dependence of the amplitudes, six out of eight mathematically-allowed solutions can be eliminated for the magnitudes and phases of the amplitudes and shown that this new S-wave state has isospin zero. Requiring a reasonable behavior for the isospin-one P wave shows that the S' amplitude has a slow phase variation through the peak region.
Date: June 1, 1978
Creator: Cohen, D.; Ayres, D.S.; Diebold, R.; Kramer, S.L.; Pawlicki, A.J. & Wicklund, A.B.
Partner: UNT Libraries Government Documents Department

Neutrino-oscillation search with cosmic-ray neutrinos

Description: It is shown that a sensitive search for neutrino oscillations involving more flavors than just nu/sub e/ and nu/sub ..mu../ is provided by measurement of the ratio of the total interaction rates of upward- and downward-going cosmic-ray neutrinos within a massive (approx. 10 kiloton) detector. Assuming mixing between all pairs of nu/sub e/, nu/sub ..mu../ and nu/sub tau/, the experiment is capable of observing time-averaging probabilities < P/sub e tau/>/sub t/ of magnitude set by mixing strengths corresponding to, e.g., the d- to s-quark mixing strength, and of reaching the limit ..delta..m/sub ij//sup 2/ identical with vertical bar m/sub i//sup 2/-m/sub j//sup 2/ vertical bar approx. = 10/sup -4/ eV/sup 2/, where m/sub i/, m/sub j/ are neutrino mass eigenstates, and P/sub e tau/ and p/sub ..mu.. tau/ are the probabilities for nu/sub e/ and nu/sub ..mu../, respectively, to oscillate into nu/sub tau/ after traversing a distance L approx. = diameter of the earth.
Date: October 1, 1982
Creator: Ayres, D.S.; Gaisser, T.K.; Mann, A.K. & Shrock, R.E.
Partner: UNT Libraries Government Documents Department

Nonaccelerator physics working group summary

Description: The Nonaccelerator Physics Working Group set itself the task of predicting the contributions of nonaccelerator experiments to particle physics during the 1990s, in order to assess the needs for new experimental facilities. The main topics studied by the subgroups were: (1) the possibility of doing particle physics experiments with high energy cosmic rays from astrophysical sources; (2) the prospects for experiments which seek to measure the masses of neutrinos and the mixing of neutrino flavors; (3) an examination of the implications for proton decay of recent theoretical developments in grand unified and string theories. Other topics included a survey of magnetic monopole searches, an assessment of future prospects for double-beta-decay and nucleon-decay experiments, and a review of recent progress on neutrino and dark-matter detectors based on quasiparticles in superconductors and phonons in crystals.
Date: January 1, 1986
Creator: Ayres, D.S.; Beier, E.W.; Cherry, M.L. & Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Prospects for future experiments to search for nucleon decay

Description: We review the status of theoretical expectations and experimental searches for nucleon decay, and predict the sensitivities which could be reached by future experiments. For the immediate future, we concur with the conclusions of the 1982 Summer Workshop on Proton Decay Experiments: all detectors now in operation or construction will be relatively insensitive to some potentially important decay modes. Next-generation experiments must therefore be designed to search for these modes, and should be undertaken whether or not present experiments detect nucleon decay in other modes. These future experiments should be designed to push the lifetime limits on all decay modes to the levels at which irreducible cosmic-ray neutrino-induced backgrounds become important. Since the technology for these next-generation experiments is available now, the timetable for starting work on them will be determined by funding constraints and not by the need for extensive development of detectors. Efforts to develop advanced detector techniques should also be pursued, in order to mount more sensitive searches than can be envisioned using current technology, or to provide the most precise measurements possible of the properties of the nucleon decay interaction if it should occur at a detectable rate.
Date: January 1, 1982
Creator: Ayres, D.S.; Heller, K.; LoSecco, J.; Mann, A.K.; Marciano, W.; Shrock, R.E. et al.
Partner: UNT Libraries Government Documents Department

Properties of the. omega. p resonance at 1. 8 GeV observed in p polarized p. -->. p. omega. p at 11. 75 GeV/c

Description: Preliminary results from a sample of approx. 20,000 events of the reaction pp..-->..p..omega..p obtained using the ZGS 11.75-GeV/c polarized proton beam and the Effective Mass Spectrometer are presented. An enhancement in the ..omega..p mass distribution with mass 1.810 +- 0.025 GeV and width 0.140 +- 0.040 GeV is observed. The t distribution of this enhancement shows a pronounced dip near -t = 0.2 GeV/sup 2/; this dip suggests that the production mechanism is mostly ..omega..-exchange. The decay angular distributions are consistent with a spin-parity of 2/sup 3 -/. 4 figures.
Date: January 1, 1980
Creator: Arenton, M.W.; Ayres, D.S.; Diebold, R.; May, E.N.; Nodulman, L.; Sauer, J.R. et al.
Partner: UNT Libraries Government Documents Department

Evidence for observation of underground muons from Cygnus X-3

Description: We have observed evidence for an average underground muon flux of approx. = 7 x 10/sup -11/ cm/sup -2/ s/sup -1/ which points back to the x-ray binary Cygnus X-3 and which exhibits the 4.8 h periodicity observed for other radiation from this source. These observations cannot be explained by conventional models of the propagation and interaction of cosmic rays. 13 refs., 2 figs.
Date: January 1, 1985
Creator: Bartelt, J.; Courant, H.; Heller, K.; Heppelmann, S.; Joyce, T.; Peterson, E.A. et al.
Partner: UNT Libraries Government Documents Department

Construction and operation of a drift-collection calorimeter

Description: Large areas planar drift chambers with long drift distance (up to 50 cm) have been developed for possible use in the new Soudan 2 nucleon decay detector. Design goals included fine sampling to determine the topology of complex events with several low-energy tracks. The large scale of the experiment (> 1000 metric tons) required large area inexpensive chambers, which also had good position resolution and multi-track separation. The chambers were to be installed between thin sheets of steel to form a finegrained detector. A second goal was the sampling of dE/dx with each position measurement, in order to determine the direction and particle identity of each track. In this paper we report on the construction and operation of a prototype dectector consisting of 50 chambers, separated by 3 mm-thick steel plates. Readout of drift time and pulse height from anode wires and an orthogonal grid of bussed cathode pads utilized 6-bit flash ADC's. This application of the drift-collection calorimeter technique to a nucleon decay detector follows the investigation by a number of groups of calorimeters for high energy detectors based on long drifting.
Date: January 1, 1984
Creator: Ambats, I.; Ayres, D.S.; Dawson, J.W.; Hoftiezer, J.H.; Mann, W.A.; May, E.N. et al.
Partner: UNT Libraries Government Documents Department

The MINOS long-baseline experiment at Fermilab

Description: The MINOS (Main Injector Neutrino Oscillation Search) long-baseline experiment will search for neutrino oscillations by measuring an intense {nu}{sub {mu}} beam at the end of a 730 km flight path. The 10,000 ton MINOS far detector will utilize magnetized steel plates interleaved with track chambers to reconstruct event topologies and to measure the energies of the muons, hadrons and electromagnetic showers produced by neutrino interactions. The experiment is designed to detect {nu}{sub {mu}} {r_arrow} {nu}{sub {tau}} and {nu}{sub {mu}} {r_arrow} {nu}{sub e} oscillations with {Delta}m{sup 2} {ge} 0.001 eV{sup 2} and sin{sup 2} (2{theta}) {ge} 0.01. Any oscillation signal observed can be verified and studied by several independent tests: a near/far rate comparison, the NC/CC event ratio, the CC and NC event energy spectra, and the identification of electrons and {tau} leptons. The neutrino beam can be operated in both wide-band and narrow-band configurations, allowing the detailed study oscillation phenomena. The experiment is scheduled to begin operation in 2001.
Date: January 2, 1997
Creator: Ayres, D.S.
Partner: UNT Libraries Government Documents Department

Observation of atmospheric neutrino oscillations in Soudan 2.

Description: The effects of oscillations of atmospheric {nu}{sub {mu}} are observed in the 5.90 fiducial kiloton-year exposure of the Soudan 2 detector. An unbinned maximum likelihood analysis of the neutrino L/E distribution has been carried out using the Feldman-Cousins prescription. The probability of the no oscillation hypothesis is 5.8 x 10{sup -4}. The 90% confidence allowed region in the sin{sup 2} 2{theta}, {Delta}m{sup 2} plane is presented.
Date: August 15, 2003
Creator: Sanchez, M.; Allison, W. W. M.; Alner, G. J.; Ayres, D. S.; Barrett, W. L.; Goodman, M.C. et al.
Partner: UNT Libraries Government Documents Department

Nucleon decay experiments: status and prospects

Description: We survey the current status and future prospects of experiments to search for nucleon decay. Results from current experiments are summarized, and the background rejection capabilities of various techniques are described. We discuss the prospects for improved sensitivity in the new experiments that are now coming into operation, and the opportunities for the next generation of detectors. 33 refs., 2 figs., 4 tabs.
Date: January 1, 1986
Creator: Ayres, D.S.; Beier, E.W.; D'Ettorre Piazzoli, B.; Ernwein, J.; Gaisser, T.K.; Seidel, S. et al.
Partner: UNT Libraries Government Documents Department