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in creator/contributor: "Napolitano, J."

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Performance of the RADPHI Detector and Trigger in a High Rate Tagged Photon Beam

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.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

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

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… more

Date: September 1, 2006

Creator: Ungaro, M.; Stoler, P.; Aznauryan, I.; Burkert, V. D.; Joo, K.; Smith, L. C. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

CEBAF at higher energies

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.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Deuteron photodisintegration: Data and plans

We review existing data for the exclusive reaction {gamma}d {yields} pn at photon energies above {approx} 1 GeV. We compare these data to various models, most notably those which rely on fundamental quark and gluon degrees of freedom. We include a discussion of future plans for related measurements.

Date: September 1, 1993

Creator: Napolitano, J.; Anthony, P. & Arnold, R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

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

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 … more

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.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

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

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… more

Date: January 1, 1989

Creator: Young, L.; Coulter, K.; Gilman, R. A.; Holt, R. J.; Kinney, E. R.; Kowalczyk, R. S. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

High energy deutron photodisintegration

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.,… more

Date: January 1, 1989

Creator: Napolitano, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Internal polarized targets

Internal polarized targets offer a number of advantages over external targets. After a brief review of the basic motivation and principles behind internal polarized targets, the technical aspects of the atomic storage cell will be discussed in particular. Sources of depolarization and the means by which their effects can be ameliorated will be described, especially depolarization by the intense magnetic fields arising from the circulating particle beam. The experience of the Argonne Novosibirsk… more

Date: January 1, 1989

Creator: Kinney, E. R.; Coulter, K.; Gilman, R.; Holt, R. J.; Kowalczyk, R. S.; Napolitano, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Measurement of Two-Body Deuteron Photodisintegration at High Photon Energies and Theta CM = 90 0

The authors report preliminary results from a measurement of the process /sup 2/H(..gamma..,p)n at theta/sub CM/ = 90/sup 0/ and for photon energies between 0.8 and 1.6 GeV. The results are compared to a conventional calculation based on meson-exchange and to models based on sub-nucleonic degrees of freedom. We find strong disagreement with the meson-exchange calculation, and best agreement with simple constituent counting at the highest energies.

Date: January 1, 1988

Creator: Napolitano, J.; Freedman, S. J.; Geesaman, D. F.; Gilman, R.; Green, M. C.; Holt, R. J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

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

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… more

Date: January 1, 1988

Creator: Holt, R.J.; Gilman, R.; Kinney, E.R.; Kowalczyk, R.S.; Napolitano, J.; Young, L. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Two-Body Photodisintegration of the Deuteron Above 1 GeV

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 e… more

Date: January 1, 1988

Creator: Holt, R. J.; Freedman, S. J.; Geesaman, D. F.; Gilman, R.; Green, M. C.; Jackson, H. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

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

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.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Search for Neutrino Oscillations at LAMPF

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.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

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

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.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

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

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… more

Date: January 1, 1985

Creator: Holt, R. J.; Green, M. C.; Young, L.; Kowalczyk, R. S.; Geesaman, D. F.; Zeidman, B. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

PEP-14 data acquisition system

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 mappe… more

Date: June 1, 1979

Creator: Madden, P.B.; Besset, D.; Freedman, S.J.; Harris, F.A.; Horne, C.P.; Losty, M.J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department