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Title: Pentaquark, cusp, and rescattering in single kaon photoproduction off deuterium

Abstract

In very well-defined parts of the phase space, KN and {lambda}N rescattering depend on on-shell elementary matrix elements and on the low momentum components of the deuteron wave function. This provides us with the unique opportunity to study details in the scattering amplitudes that may have escaped the analysis of reactions induced on a nucleon target by kaon and hyperon beams at low energies. When folded with a typical experimental mass resolution, a narrow state with a width of 1 MeV would contribute by no more than 10% to the KN mass spectrum. On the contrary, a cusp would be easily detected near the {sigma} production threshold in the {lambda}N mass spectrum.

Authors:
 [1]
  1. Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)
Publication Date:
OSTI Identifier:
20990933
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 1; Other Information: DOI: 10.1103/PhysRevC.75.014002; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; CUSPED GEOMETRIES; DEUTERIUM; DEUTERONS; HYPERON BEAMS; KAONS; MASS RESOLUTION; MASS SPECTRA; MATRIX ELEMENTS; MEV RANGE 01-10; NUCLEONS; PHASE SPACE; PHOTOPRODUCTION; RESCATTERING; SCATTERING AMPLITUDES; WAVE FUNCTIONS

Citation Formats

Laget, J. M. Pentaquark, cusp, and rescattering in single kaon photoproduction off deuterium. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.014002.
Laget, J. M. Pentaquark, cusp, and rescattering in single kaon photoproduction off deuterium. United States. doi:10.1103/PHYSREVC.75.014002.
Laget, J. M. Mon . "Pentaquark, cusp, and rescattering in single kaon photoproduction off deuterium". United States. doi:10.1103/PHYSREVC.75.014002.
@article{osti_20990933,
title = {Pentaquark, cusp, and rescattering in single kaon photoproduction off deuterium},
author = {Laget, J. M.},
abstractNote = {In very well-defined parts of the phase space, KN and {lambda}N rescattering depend on on-shell elementary matrix elements and on the low momentum components of the deuteron wave function. This provides us with the unique opportunity to study details in the scattering amplitudes that may have escaped the analysis of reactions induced on a nucleon target by kaon and hyperon beams at low energies. When folded with a typical experimental mass resolution, a narrow state with a width of 1 MeV would contribute by no more than 10% to the KN mass spectrum. On the contrary, a cusp would be easily detected near the {sigma} production threshold in the {lambda}N mass spectrum.},
doi = {10.1103/PHYSREVC.75.014002},
journal = {Physical Review. C, Nuclear Physics},
number = 1,
volume = 75,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • In very well defined part of the phase space, K N and {Lambda} N rescattering depend on on-shell elementary matrix elements and on the low momentum components of the deuteron wave function. This provides us with the unique opportunity to study details in the scattering amplitudes that may have escaped the analysis of reactions induced on a nucleon target by Kaon and Hyperon beams at low energies. When folded with a typical experimental mass resolution, a narrow state with a width of 1 {approx} MeV would contribute by no more than 10% to the KN mass spectrum. On the contrary,more » a cusp would be easily detected near the {Sigma} production threshold in the {Lambda} N mass spectrum.« less
  • We examine cross sections for the processes {gamma} N {yields} NK{bar K} in the framework of a phenomenological Lagrangian. We include contributions from {Lambda} and {Sigma} resonances up to spin 3/2, as well as those from an exotic {Theta}{sup +}. We allow the {Theta}{sup +} to have spin 1/2 or 3/2, with either positive or negative parity in each case. We also allow the state to be either isovector or isoscalar. We find that the scenario that most closely matches observations at Jefferson Laboratory requires a very large coupling of the {Theta}{sup +} to NK*.
  • We examine cross sections for the processes {gamma}N{yields}NKK in the framework of a phenomenological Lagrangian. We include contributions from {lambda} and {sigma} resonances up to spin 3/2, as well as those from an exotic {theta}{sup +}. We allow the {theta}{sup +} to have spin 1/2 or 3/2, with either positive or negative parity in each case. We also allow the state to be either isovector or isoscalar. We find that the scenario that most closely matches observations at Jefferson Laboratory requires a moderately large coupling of the {theta}{sup +} to NK*.
  • We searched for the {Phi}{sup --}(1860) pentaquark in the photoproduction process off the deuteron in the {Xi}{sup -} {pi}{sup -} decay channel using CLAS. The invariant mass spectrum of the {Xi}{sup -} {pi}{sup -} system does not indicate any statistically significant enhancement near the reported mass M = 1.860 GeV. The statistical analysis of the sideband-subtracted mass spectrum yields a 90% confidence level upper limit of 0.7 nb for the photoproduction cross section of {Phi}{sup --}(1860) with a consecutive decay into {Xi}{sup -} {pi}{sup -} in the photon energy range 4.5 GeV < E{sub {gamma}} < 5.5 GeV.
  • We searched for the Φ⁻⁻(1860) pentaquark in the photoproduction process off the deuteron in the Ξ⁻π⁻-decay channel using CLAS. The invariant-mass spectrum of the Ξ⁻π⁻ system does not indicate any statistically significant enhancement near the reported mass M=1.860 GeV. The statistical analysis of the sideband-subtracted mass spectrum yields a 90%-confidence-level upper limit of 0.7 nb for the photoproduction cross section of Φ⁻⁻(1860) with a consecutive decay intoΞ⁻π⁻ in the photon-energy range 4.5GeVγ<5.5GeV.
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