Kaon photoproduction: Background contributions, form factors, and missing resonances

Abstract

The photoproduction p(␥,K ϩ )⌳ process is studied within a field-theoretic approach. It is shown that the background contributions constitute an important part of the reaction dynamics. We compare predictions obtained with three plausible techniques for dealing with these background contributions. It appears that the extracted resonance parameters drastically depend on the applied technique. We investigate the implications of the corrections to the functional form of the hadronic form factor in the contact term, recently suggested by Davidson and Workman ͓Phys. Rev. C 63, 025210 ͑2001͔͒. The role of background contributions and hadronic form factors for the identification of the quantum numbers of ''missing'' resonances is discussed.

Electromagnetic production of kaons near threshold

“…It is obvious that significant improvement in the χ 2 would be obtained once we included this resonance, especially when the S 01 (1800) is used. This result corroborates the finding of Janssen et al [6], since the large hadronic cut-off requires another mechanism to damp the cross section at high energies. This is achieved by a destructive interference between the hyperon resonance contribution and other background terms.…”

“…Later, Janssen et al [6] found that the use of hyperon resonances S 01 (1800) and P 01 (1810), simultaneously, is desired in order to obtain the hadronic form factor cut-off greater than 1500 MeV in their model. The larger value of cut-off is desired in the kaon photoproduction because they argued that the value of 800 MeV found in Ref.…”

“…Most of them have been performed in the framework of tree-level isobar models [1][2][3][4][5][6][7], coupled channel approaches [8][9][10][11][12], Regge model [13], or quark models [14,15]. Extending the energy range of isobar models to higher region by utilizing Regge formalism has also been pursued recently [16][17][18][19].…”

Kaon electromagnetic production: constraints set by new data

“…The hadron structure in the strong vertexes is taken into account by means of the dipole type form factors [5] introduced in the gauge-invariant way as proposed by Davidson and Workman [9].…”

“…Most of the models have, however, problems with a reasonable description of new experimental data collected in JLab and Bonn [1]. Among the models which can still provide a satisfactory prediction in comparison with new data are the latest isobaric ones, Saclay-Lyon [2,3], Kaon-MAID [4], and Janssen et al [5].…”