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High energy deutron photodisintegration

Description: Results are presented for two-body deuteron photodisintegration, i.e., d(/gamma/,p)n, at /theta//sub CM/ = 90/degree/ and for photon energies up to 1.6 GeV. These results are discussed in the light of several theoretical models. The data suggest that, at the highest energies, the energy dependence of the cross section is that given by simple constituent counting. We also discuss the need for additional work, both experimental and theoretical, to help resolve conflicting points of view. 4 refs., 4 figs.
Date: January 1, 1989
Creator: Napolitano, J.
Partner: UNT Libraries Government Documents Department

A search for (anti nu/sub. mu. /,anti nu/sub e/) oscillations at LAMPF (Los Alamos Meson Physics Facility)

Description: Reasons for searching for neutrino oscillations are discussed briefly. An experiment in progress at the LAMPF beam stop is discussed which aims to be sensitive to the appearance of anti nu/sub e/ from anti nu/sub ..mu../ at a level of approximately 10/sup -3/. Progress, status and upcoming plans for this experiment are also discussed.
Date: February 1, 1987
Creator: Napolitano, J.
Partner: UNT Libraries Government Documents Department

Measurement of the energy dependent beta asymmetry in the decay of /sup 8/Li

Description: Progress is reported on a new measurement of the beta decay asymmetry in /sup 8/Li. Polarized /sup 8/Li is produced via the reaction /sup 7/Li(d,p)/sup 8/Li using vector polarized deuterons from a crossed beam polarized source. Plastic scintillation electron counters are used to measure asymmetry, tensor polarization correlation and to monitor beam current. Results are graphed and systematic error sources are discussed. 4 refs. (LEW)
Date: January 1, 1985
Creator: Bigelow, R.A.; Quin, P.A.; Freedman, S.J. & Napolitano, J.
Partner: UNT Libraries Government Documents Department

CEBAF at higher energies

Description: This report summarizes topics in hadron spectroscopy and production which could be addressed at CEBAF with an energy upgrade to E{sub gamma} = 8 GeV and beyond. The topics discussed include conventional meson and baryon spectroscopy, spectroscopy of exotica (especially molecules and hybrids), CP and CPT tests using {phi} mesons, and new detector and accelerator options.
Date: December 31, 1994
Creator: Barnes, T. & Napolitano, J.
Partner: UNT Libraries Government Documents Department

Search for neutrino oscillations at LAMPF

Description: The decays of stopped pions in the LAMPF beam stop present a unique opportunity to probe neutrino oscillations in the mass region of deltam/sup 2/ approx.0.1eV/sup 2/ and mixing parameters as low was sin/sup 2/2THETA approx.10/sup -3/. The appearance of anti nu/sub e/ will be measured with high sensitivity by Experiment 645 during the run cycle that begins in the summer of 1986.
Date: January 1, 1986
Creator: Harper, R.W.; Ling, T.Y.; Mitchell, J.W.; Romanowski, T.A.; Smith, E.S.; Timko, M. et al.
Partner: UNT Libraries Government Documents Department

Tests of a polarized source of hydrogen and deuterium based on spin-exchange optical pumping and a storage cell for polarized deuterium

Description: A novel laser-driven polarized source of hydrogen and deuterium which is based on the principle of spin-exchange optical pumping has been developed at Argonne. The advantages of this method over conventional polarized sources for internal target experiments is discussed. At present, the laser-driven polarized source delivers hydrogen 8 x 10 W atoms/s with a polarization of 24% and deuterium at 6 x 10 W atoms/s with a polarization of 25%. A passive storage cell for polarized deuterium was tested in the VEPP-3 electron storage ring. The storage cell was found to increase the target thickness by approximately a factor of three and no loss in polarization was observed. 10 refs., 4 figs., 2 tabs.
Date: January 1, 1988
Creator: Holt, R.J.; Gilman, R.; Kinney, E.R.; Kowalczyk, R.S.; Napolitano, J.; Young, L. et al.
Partner: UNT Libraries Government Documents Department

Two-body photodisintegration of the deuteron above 1 GeV

Description: One of the central issues in nuclear physics is the identification of clear signatures for quarks in nuclei. A guiding principle in this search is to perform experiments with high energy electromagnetic probes of the simplest nucleus, the deuteron, a system which is particularly amenable to theoretical interpretation. It has long been known that the quark counting rules seem to apply for electron elastic scattering from the pion and nucleon. However, the rapid decline in the cross section for electron scattering from the deuteron, a six-quark system, renders an experiment at high momentum transfer unfeasible. Clearly, the dimensional-scaling region is not reached for electron-deuteron elastic scattering as indicated. This led Brodsky and Chertok to analyze these data in terms of the reduced nuclear amplitudes and produce, in effect, scaling at a lower momentum transfer. Presently, this is the only known case where the reduced nuclear amplitude analysis seems to apply. In the present work we abandon elastic electron scattering in favor of an exclusive photoreaction with the deuteron. The simplest process involving a nucleus is the ..gamma..d ..-->.. pn reaction. Here, n = 13 and an s/sup -11/ dependence is expected where the quark counting rules are valid. Naively, one would expect that the energy region where the quark counting rules are valid to be most naturally described in terms of a quark or parton basis rather than a nucleon basis, and thereby provide a signature quark effects in nuclei. Hitherto no s/sup -11/ dependence has been observed for the data below 1 GeV. As a test of the energy-dependence for the ..gamma..d ..-->.. pn reaction, we have performed the first measurements for this process above 1 GeV.
Date: January 1, 1988
Creator: Holt, R.J.; Freedman, S.J.; Geesaman, D.F.; Gilman, R.; Green, M.C.; Jackson, H.E. et al.
Partner: UNT Libraries Government Documents Department

Prospect for observation of polarization in electron-deuteron elastic scattering at high momentum transfer

Description: A measurement of the charge and quadrupole form factors of the deuteron would address the most fundamental questions in nuclear physics: validity of perturbative QCD at relatively low momentum transfer, effect of isoscalar meson-exchange currents, and the deuteron structure at short range. Polarization methods will be required in order to provide the separation of these form factors. We propose that the high current of electrons in a storage ring be employed in order to scatter electrons from a gaseous, tensor-polarized, deuterium target.
Date: January 1, 1985
Creator: Holt, R.J.; Green, M.C.; Young, L.; Kowalczyk, R.S.; Geesaman, D.F.; Zeidman, B. et al.
Partner: UNT Libraries Government Documents Department

Development of a polarized deuterium target to measure T/sub 20/ in electron storage rings

Description: The development of a polarized deuterium target to measure the analyzing power in electron scattering from the deuteron at the highest possible momentum transfer is described. Two areas of research have been simultaneously pursued: the development of a storage cell for polarized atoms (ANL and INP) and the development of a high-flux laser-driven source of polarized deuterium (ANL). The successful combination of these two technological developments will produce a polarized target having a figure of merit of np/sub zz//sup 2/ approx. np/sub z//sup 2/ approx. 10/sup 14/ cm/sup /minus/2/. The progress to date, including, feasibility tests of the storage cell concept, design of a high-density storage cell ad the development of the laser-driven source will be described. 14 refs., 7 figs.
Date: January 1, 1989
Creator: Young, L.; Coulter, K.; Gilman, R.A.; Holt, R.J.; Kinney, E.R.; Kowalczyk, R.S. et al.
Partner: UNT Libraries Government Documents Department

PEP-14 data acquisition system

Description: A real-time software system was developed for the VAX 11/780 which employs ten processes cooperating concurrently in the task of data acquisition and on-line analysis for the Free Quark Search experiment at the new colliding beam storage ring facility (PEP) located at the Stanford Linear Accelerator Center. The system utilizes most of the resources available to the applications programer under VAX 11/780 VMS, including interprocess communication via mailbox, global event flag cluster, and mapped global section, and is written primarily in FORTRAN IV PLUS with time-critical portions in MACRO-11. A discussion of the system architecture, implementation, and performance is given. 6 figures, 1 table.
Date: June 1, 1979
Creator: Madden, P.B.; Besset, D.; Freedman, S.J.; Harris, F.A.; Horne, C.P.; Losty, M.J. et al.
Partner: UNT Libraries Government Documents Department

A proposal to search for neutrino oscillations with high sensitivity in the appearance channels. nu. sub. mu. yields. nu. sub e and. nu. sub. mu. yields. nu. sub e

Description: An experiment is proposed to search concurrently for {nu}{sub {mu}} {yields} {nu}{sub e} and {bar {nu}}{sub {mu}} {yields} {bar {nu}{sub e} oscillations with high sensitivity at LAMPF. The detector consists of a tank with 200 tons of dilute liquid scintillator with 850 10-in. photomultiplier tubes mounted on the inside tank covering 28% of the surface. Both Cerenkov light and scintillation light will be detected. The tank will reside inside the existing E645 veto shield and the experiment will make use of the present A6 beam-stop neutrino source. After two years of data collection, 90% confidence level limits on {bar {nu}{sub mu}}({nu}{sub {mu}}) {yields} {bar {nu}}{sub e}({nu}{sub e}) mixing strengths of 2.7(2.7) {times} 10{sup {minus}4} can be obtained for all {Delta}m{sup 2} > 1 eV{sup 2}. Similarly, for maximal mixing the 90% C.L. limits on {Delta}m{sup 2} are 1.7(4.0) {times} 10{sup {minus}2}. This experiment will, therefore, provide the world's best terrestrial limits on {nu}{sub {mu}} {yields} {nu}{sub e}} oscillations. Other physics to be obtained includes measurements of the charged current reactions {nu}{sub e}C {yields} e{sup {minus}}N and {nu}{sub {mu}}C {yields} {mu}{sup {minus}}N, of the inelastic neutral current reaction {nu}C {yields} {nu}C* (15.11- MeV {gamma}), and a search for the rare decays {pi}{sup 0} {yields} {nu}{bar {nu}} and {eta} {yields} {nu}{bar {nu}}.
Date: August 1, 1990
Creator: Lu, X-Q.; Yodh, G. (California Univ., Irvine, CA (USA)); Fung, S.Y.; Kang, J.H.; Shen, B.C.; VanDalen, G.J. (California Univ., Riverside, CA (USA)) et al.
Partner: UNT Libraries Government Documents Department

Performance of the radphi detector and trigger in a high rate tagged photon beam

Description: We describe the design and operation of a detector system for measuring all-photon decays of mesons photoproduced in a tagged photon beam with energies between 4.3 and 5.4 GeV and a flux of 5×107 tagged photons per second. Photons from meson decays were detected with a lead-glass calorimeter with an energy resolution of 11% at 1 GeV. Various veto and trigger components were also present. Final states with as many as six photons were successfully detected and reconstructed.
Date: January 1, 2007
Creator: Jones, R.T.; Bogue, T.; Evans, B.E.; Kornicer, M.; Dzierba, A.R.; Gardner, R. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the N --> Delta^+ (1232) Transition at High-Momentum Transfer by pi^0 Electroproduction

Description: We report a new measurement of the exclusive electroproduction reaction gamma*_p --> pi0_p to explore the evolution from soft nonperturbative physics to hard processes via the Q2 dependence of the magnetic (M1+), electric (E1+), and scalar (S1+) multipoles in the N --> Delta transition. 9000 differential cross section data points cover W from threshold to 1.4 GeV/c2, 4pi center-of-mass solid angle, and Q2 from 3 to 6 GeV2/c2, the highest yet achieved. It is found that the magnetic form factor G^*M decreases with Q2 more steeply than the proton magnetic form factor, the ratio E1+/M1+ is small and negative, indicating strong helicity nonconservation, and the ratio S1+/M1+ is negative, while its magnitude increases with Q2.
Date: September 1, 2006
Creator: Ungaro, M.; Stoler, P.; Aznauryan, I.; Burkert, V. D.; Joo, K.; Smith, L. C. et al.
Partner: UNT Libraries Government Documents Department