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Title: Photo-Production of Proton Antiproton Pairs

Abstract

Results are reported on the reaction gammap --> ppp-bar . A high statistic data set was obtained at the Thomas Jefferson National Accelerator Facility utilizing the CLAS detector and a tagged photon beam of 4.8 to 5.2 GeV incident on a liquid hydrogen target. The focus of this study was to search for possible intermediate resonances which decay to proton-antiproton. Both final state protons were detected in the CLAS apparatus whereas the antiproton was identified via missing mass. General features of the data are presented along with results on narrow and broad resonance studies.

Authors:
;
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA
Sponsoring Org.:
USDOE - Office of Energy Research (ER)
OSTI Identifier:
912628
Report Number(s):
JLAB-PHY-07-686; DOE/OR/23177-0116
TRN: US0800467
DOE Contract Number:
AC05-06OR23177
Resource Type:
Conference
Resource Relation:
Journal Name: AIP; Journal Volume: 892; Conference: Quark Confinement and the Hadron Spectrum 7, Ponta Delgada, Azores, Portugal, 2-7 Sep 2006
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; 43 PARTICLE ACCELERATORS; ANTIPROTONS; BAG MODEL; CEBAF ACCELERATOR; DECAY; HADRONS; HYDROGEN; INTERMEDIATE RESONANCE; MISSING MASS; PHOTON BEAMS; PROTONS; RESONANCE; STATISTICS

Citation Formats

Paul Eugenio, and Burnham Stokes. Photo-Production of Proton Antiproton Pairs. United States: N. p., 2007. Web. doi:10.1063/1.2714390.
Paul Eugenio, & Burnham Stokes. Photo-Production of Proton Antiproton Pairs. United States. doi:10.1063/1.2714390.
Paul Eugenio, and Burnham Stokes. Thu . "Photo-Production of Proton Antiproton Pairs". United States. doi:10.1063/1.2714390. https://www.osti.gov/servlets/purl/912628.
@article{osti_912628,
title = {Photo-Production of Proton Antiproton Pairs},
author = {Paul Eugenio and Burnham Stokes},
abstractNote = {Results are reported on the reaction gammap --> ppp-bar . A high statistic data set was obtained at the Thomas Jefferson National Accelerator Facility utilizing the CLAS detector and a tagged photon beam of 4.8 to 5.2 GeV incident on a liquid hydrogen target. The focus of this study was to search for possible intermediate resonances which decay to proton-antiproton. Both final state protons were detected in the CLAS apparatus whereas the antiproton was identified via missing mass. General features of the data are presented along with results on narrow and broad resonance studies.},
doi = {10.1063/1.2714390},
journal = {AIP},
number = ,
volume = 892,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2007},
month = {Thu Feb 01 00:00:00 EST 2007}
}

Conference:
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  • Results are reported on the reaction {gamma}p {yields} ppp-bar. A high statistic data set was obtained at the Thomas Jefferson National Accelerator Facility utilizing the CLAS detector and a tagged photon beam of 4.8 to 5.2 GeV incident on a liquid hydrogen target. The focus of this study was to search for possible intermediate resonances which decay to proton-antiproton. Both final state protons were detected in the CLAS apparatus whereas the antiproton was identified via missing mass. General features of the data are presented along with results on narrow and broad resonance studies.
  • Events of the type anti ppmore » $Yields$ K$sup -$K$sup +$, $pi$$sup - $$pi$$sup +$ were studied at 0.79 to 2.43 GeV/c. Differential cross sections and Legendre coefficient ratios are shown. Resonances found as a result of model fitting showing spin--parity assignment versus mass squared are also shown. (JFP)« less
  • The polarization parameter for the interactions anti pp ..-->.. ..pi../sup -/..pi../sup +/ and anti pp ..-->.. K/sup -/K/sup +/ was measured over essentially the full angular range at 11 momenta between 1.0 and 2.2 GeV/c. A proton target polarized perpendicular to the scattering plane was used. The experiment measured the angles and momenta of both outgoing particles using wire spark chambers and the field of the polarized target magnet. Between 1000 and 5300 ..pi../sup -/..pi../sup +/ events, and 140 and 1300 K/sup -/K/sup +/ events, were measured at each momentum. As a check, one obtained differential cross sections for antimore » pp ..-->.. ..pi../sup -/..pi../sup +/ which are in excellent agreement with previous results. The polarizations for both channels are very large and positive over much of the angular range. Preliminary results of a fit to the cross sections and asymmetries for anti pp ..-->.. ..pi../sup -/..pi../sup +/ show strong evidence for three new resonances at 2.14, 2.36, and 2.40 GeV/c/sup 2/.« less
  • Hard deuteron photodisintegration has been investigated for 20 years, as its cross section follows the constituent counting rule and it provides insight into the interplay between hadronic and quark-gluon degrees of freedom in high-momentum transfer exclusive reactions. We have now measured for the first time hard pp-pair disintegration in the reaction gamma 3He-->pp+n, using kinematics corresponding to a spectator neutron. Cross sections were measured for 90 deg. c.m. at 8 beam energies, from 0.8 to 4.7 GeV. Preliminary results will be presented and compared to the hard deuteron photodisintegration data.