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Title: Photoproduction of Λ and Σ0 Hyperons off Protons in the Nucleon Resonance Region using CLAS at Jefferson Lab

Abstract

The differential cross section and hyperon recoil polarizations of the photoproduction of the ground state hyperons, γ p → K+ Λ and γ p → K+ Σ0 , have been measured with the CLAS at Jefferson Lab up to a photon energy in the lab of 2.325 GeV. The results for both channels show significantly larger cross section in the middle to forward angles than have been observed previously by the SAPHIR Collaboration. Both reactions show significantly more backward peaking in the angular distributions than has previously been possible to observe. The backward peaking hints that hyperon resonances in the u-channel play a significant role in the production mechanism. In addition, in the γ p → K+ Λ reaction, a previously unobserved bump in the cross section was observed at forward angles, centered on a W of 1.95 GeV with a width of approximately Γ = 100 MeV. In both γ p → K+ Y reactions the recoil polarization in the forward direction seems reasonably well reproduced by t-channel interferences in a Regge model calculation as well as hadrodynamic models that include kaon resonances in the t-channel. The recoil polarization for γ p → K+ Λ shows a significant enhancementmore » around a W of 1.9 GeV in the backward angles, which is a sign of resonance activity in this vicinity. The polarization of γ p → K+ Σ0 at backward angles is, in contrast, less pronounced and mostly consistent with zero.« less

Authors:
 [1]
  1. Carnegie Mellon Univ., Pittsburgh, PA (United States)
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
824902
Report Number(s):
JLAB-PHY-02-103; DOE/ER/40150-2749
TRN: US0402239
DOE Contract Number:  
AC05-84ER40150
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: TH: Thesis (Ph.D.); Submitted to Carnegie Mellon Univ., Pittsburgh, PA (US); PBD: 1 Dec 2002
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ANGULAR DISTRIBUTION; CROSS SECTIONS; DIFFERENTIAL CROSS SECTIONS; GROUND STATES; HYPERONS; KAONS; NUCLEONS; PHOTONS; PHOTOPRODUCTION; POLARIZATION; PROTONS; RESONANCE; T CHANNEL; U CHANNEL

Citation Formats

McNabb, John W.C. Photoproduction of Λ and Σ0 Hyperons off Protons in the Nucleon Resonance Region using CLAS at Jefferson Lab. United States: N. p., 2002. Web. doi:10.2172/824902.
McNabb, John W.C. Photoproduction of Λ and Σ0 Hyperons off Protons in the Nucleon Resonance Region using CLAS at Jefferson Lab. United States. https://doi.org/10.2172/824902
McNabb, John W.C. 2002. "Photoproduction of Λ and Σ0 Hyperons off Protons in the Nucleon Resonance Region using CLAS at Jefferson Lab". United States. https://doi.org/10.2172/824902. https://www.osti.gov/servlets/purl/824902.
@article{osti_824902,
title = {Photoproduction of Λ and Σ0 Hyperons off Protons in the Nucleon Resonance Region using CLAS at Jefferson Lab},
author = {McNabb, John W.C.},
abstractNote = {The differential cross section and hyperon recoil polarizations of the photoproduction of the ground state hyperons, γ p → K+ Λ and γ p → K+ Σ0 , have been measured with the CLAS at Jefferson Lab up to a photon energy in the lab of 2.325 GeV. The results for both channels show significantly larger cross section in the middle to forward angles than have been observed previously by the SAPHIR Collaboration. Both reactions show significantly more backward peaking in the angular distributions than has previously been possible to observe. The backward peaking hints that hyperon resonances in the u-channel play a significant role in the production mechanism. In addition, in the γ p → K+ Λ reaction, a previously unobserved bump in the cross section was observed at forward angles, centered on a W of 1.95 GeV with a width of approximately Γ = 100 MeV. In both γ p → K+ Y reactions the recoil polarization in the forward direction seems reasonably well reproduced by t-channel interferences in a Regge model calculation as well as hadrodynamic models that include kaon resonances in the t-channel. The recoil polarization for γ p → K+ Λ shows a significant enhancement around a W of 1.9 GeV in the backward angles, which is a sign of resonance activity in this vicinity. The polarization of γ p → K+ Σ0 at backward angles is, in contrast, less pronounced and mostly consistent with zero.},
doi = {10.2172/824902},
url = {https://www.osti.gov/biblio/824902}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Dec 05 00:00:00 EST 2002},
month = {Thu Dec 05 00:00:00 EST 2002}
}

Thesis/Dissertation:
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