Electroproduction of kaons from the proton in a Regge-plus-resonance approach

Abstract

We present a Regge-plus-resonance (RPR) description of the p(e, e ′ K + )Y processes (Y = Λ, Σ 0 ) in the resonance region. The background contributions to the RPR amplitude are constrained by the high-energy p(γ, K + )Y data. As a result, the number of free model parameters in the resonance region is considerably reduced compared to typical effective-Lagrangian approaches. We compare a selection of RPR model variants, originally constructed to describe KY photoproduction, with the world electroproduction database. The electromagnetic form factors of the intermediate N * s and ∆ * s are computed in the Bonn constituent-quark model. With this input, we find a reasonable description of the p(e, e ′ K + )Y data without adding or readjusting any parameters. It is demonstrated that the electroproduction response functions are extremely useful for fine-tuning both the background and resonant contributions to the reaction dynamics.

Separated structure functions for exclusiveK+ΛandK+Σ0electroproduction at 5.5 GeV measured with CLAS

“…Several groups have stressed that the importance of the background contributions calls for a framework that accounts for both the resonant and non-resonant processes and that provides for a means to constrain both of these classes of reaction mechanisms independently [27,28].…”

“…The electroproduction observables have been shown to yield important complementary insights [27]. Some of the most important aspects of electroproduction include:…”

“…The final model included in this work was developed by the Ghent group [27], and is based on a tree-level effective field model for K + Λ and K + Σ 0 photoproduction from the proton. It differs from traditional isobar approaches in its description of the non-resonant diagrams, which involve the exchange of K and K * Regge trajectories.…”

“…In a new version of the RPR model (referred to as RPR-2011) [37], several changes relative to the previous model version (referred to as RPR-2007) [27] Neither version of the model has been constrained by fits to any of the electroproduction data.…”

Hyperon Spectroscopy at Hall B, Jefferson Lab

“…This is due, in part, to the difficulties encountered in modeling the strong interaction in the non-perturbative regime. As such, the problem has been approached through the use of effective field theories [1][2][3][4], Regge models [5] and hybrid Regge-plus-resonance (RPR) models [6,7], and more recently, through coupled-channel analyses [8][9][10][11]. All of these methods require large and precise data sets in order to constrain fitting parameters.…”