R Williams

Publications (4)1.54 Total impact

• Article: Separation of the longitudinal and transverse cross sections in the 1H(e,e′K+)Λ and 1H(e,e′K+)Σ0 reactions

  R. M. Mohring, D. Abbott, A. Ahmidouch, Ts. A. Amatuni, P. Ambrozewicz, T. Angelescu, C. S. Armstrong, J. Arrington, K. Assamagan, S. Avery, [......], T. Terasawa, H. Tsubota, G. M. Urciuoli, J. Volmer, W. Vulcan, T. P. Welch, R. Williams, S. Wood, C. Yan, B. Zeidman
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  ABSTRACT: We report measurements of cross sections for the reaction 1H(e,e′K+)Y, for both the Λ and Σ0 hyperon states, at an invariant mass of W=1.84GeV and four-momentum transfers 0.5<Q2<2(GeV/c)2. Data were taken for three values of virtual photon polarization ε, allowing the decomposition of the cross sections into longitudinal and transverse components. The Λ data are a revised analysis of prior work, whereas the Σ0 results have not been previously reported.
  Phys. Rev. C. 05/2003; 67(5).
• Article: Associated Λ production at Jefferson Lab

  O. K. Baker, S. Avery, K. Assamagan, K. Beard, J. Cha, T. Eden, P. Gueye, W. Hinton, M. Harvey, C. Keppel, [......], E. Hungerford, W. Kim, K. Kino, M. Maeda, T. Saito, T. Terasawa, H. Tsubota, L. Kramer, P. Markowitz, B. A. Raue
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  ABSTRACT: The 1H(e,e'K+)Λ and 1H(e,e'K+)Σ0 reactions were studied as a function of the squared four-momentum-transfer, Q2, and the virtual photon polarization, ɛ, thus enabling the separation of the longitudinal and transverse parts of the cross section. The existence of a sizable longitudinal component for the 1H(e,e'K+)Λ reaction seems to be indicated by these data.
  Nuclear Physics A 07/1998; 639:189-196. · 1.54 Impact Factor
• Source

  Available from: John Robert Arrington

  Article: Separation of the longitudinal and transverse cross sections in the $^{1}H(e,e'K^{+})\Lambda$ and $^{1}H(e,e'K^{+})\Sigma^{0}$ reactions

  R. M. Mohring, D. Abbott, A. Ahmidouch, T.A. Amatuni, P Ambrozewicz, T Angelescu, C. S. Armstrong, J. Arrington, K. Assamagan, S. Avery, [......], T Terasawa, H. Tsubota, G. M. Urciuoli, J Volmer, W. Vulcan, T.P. Welch, R Williams, S. Wood, C Yan, B. Zeidman
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  ABSTRACT: We report measurements of cross sections for the reaction p(e,e'K)Y, for both the Lambda and Sigma_0 hyperon states, at an invariant mass of W=1.84 GeV and four-momentum transfers 0.5<Q2<2 (GeV/c)2. Data were taken for three values of virtual photon polarization, allowing the decomposition of the cross sections into longitudinal and transverse components. The Lambda data is a revised analysis of prior work, whereas the Sigma_0 results have not been previously reported.
• Article: Λ polarization in associated K+–Λ electro-production

  L. Teodorescu, P. Guèye, T. Angelescu, O.K. Baker, R. Ent, M. Guidal, J.M. Laget, J. Mitchell, G. Niculescu, M. Vanderhaeghen, R. Williams
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  ABSTRACT: The result of a feasibility study to measure the Λ polarization in associated K+–Λ electro-production is presented. This measurement was performed in the experimental Hall C at Jefferson Lab. The scattered electron was detected in the HMS spectrometer, and the electro-produced kaon and the proton from the Λ→pπ− decay were both detected in the SOS spectrometer. This quantity is very sensitive to the elementary p(e,e′K)Λ process and gives information on resonance production, and Regge exchange, among others. The result presented was measured at Q2=1.50 (GeV/c)2 and cosθKγCM=14°. The limits of the Λ polarization, with respect to the axis, were found to be −0.21 and +0.89 with a confidence level of 68%. The result is compared to theoretical predictions based on an effective hadronic field Lagrangian model and a Regge framework model.
  Nuclear Physics A.