New fits to the reaction $\gamma p\to K^{+}\Lambda$

Abstract

The reaction $\gamma p\to K^{+}\Lambda$ has been investigated over the center-of-momentum energy, $W$, range from threshold up to 2.2 GeV in a tree-level effective Lagrangian model that incorporates most of the well-established baryon resonances with spins equal to or below 5/2. Four less well-established nucleon resonances of higher mass are also included. The fitted parameters consist, for each resonance included, of the products of the coupling strengths at the electromagnetic and strong interaction vertices and, for the less-established nucleon resonances, the total decay width. For the well-established nucleon resonances, the energy and momentum dependence of the widths is treated within a dynamical model that is normalized to give the empirical decay branching ratios on the resonance mass shells. For the less-established resonances, the total decay width is treated as a single parameter independent of the reaction kinematics. The model is used to fit recent data for the unpolarized differential cross section (CLAS), the induced hyperon polarization asymmetry, $P$ (CLAS, GRAAL, and SAPHIR), the beam spin asymmetry, $\Sigma$ (LEPS), and the double polarization observables $C_x$ and $C_z$ (CLAS). Two different fits were obtained: one that incorporates SU(3) symmetry constraints on the Born contributions to the reaction amplitude and one in which these constraints are relaxed. Explicit numerical results are given only for the first fit since the two fits gave nearly identical results for the observables and the ${\chi }^2$ per degree of freedom obtained with the second fit was only marginally better than that of the first fit ($<1$ better). Results are presented for the fitted observables at several different energies and center-of-momentum (c.m.) frame kaon angles.

28 pages, 10 figures

References in corpus (13)

• The Cosmological Parameters 2006
• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• The gamma + p to K+ + Lambda and gamma + p to K+ + Sigma0 reactions at forward angles with photon energies from 1.5 to 2.4 GeV
• First Measurement of Beam-Recoil Observables Cx and Cz in Hyperon Photoproduction
• Dynamical coupled-channel approach to hadronic and electromagnetic production of kaon-hyperon on the proton
• Measurement of beam-recoil observables Ox, Oz and target asymmetry for the reaction gamma p -> K Lambda
• Kaon photoproduction in a multipole approach
• Baryon resonances and polarization transfer in hyperon photoproduction
• Separated Structure Functions for the Exclusive Electroproduction of $K^{+}\Lambda$ and $K^{+}{\Sigma }^0$ Final States
• Further evidence for N(1900)P_{13} from photoproduction of hyperons
• Beam-Recoil Polarization Transfer in the Nucleon Resonance Region in the Exclusive $\vec{e}p\to e^{\prime }{K}^{+}\vec{\Lambda }$ and $\vec{e}p\to e^{\prime }{K}^{+}{\vec{\Sigma }}^0$ Reactions at CLAS
• Polarized Structure Function ${\sigma }_{L{T}^{\prime }}$ for $p(\vec{e},e^{\prime }{K}^{+})\Lambda$ in the Nucleon Resonance Region
• Analysis of the consistency of kaon photoproduction data with Lambda in the final state

Cited by in corpus (12)

• Faddeev fixed-center approximation to the $N\bar{K}K$ system and the signature of a $N^{\ast }(1920)(1/2^{+})$ state
• Pion- and photo-induced transition amplitudes to $\Lambda K$, $\Sigma K$, and $N\eta$
• P-wave excited baryons from pion- and photo-induced hyperon production
• Photoproduction of $K\Lambda$ on the proton
• Electromagnetic production of kaon near threshold
• Separated Structure Functions for Exclusive $K^{+}\Lambda$ and $K^{+}{\Sigma }^0$ Electroproduction at 5.5 GeV with CLAS
• Coupled $K^{+}\Lambda$ and $K^0\Lambda$ photoproduction off the nucleon: Consequences from the recent CLAS and MAMI data and the $N(1680)P_{11}$ narrow state
• Induced polarization of Λ(1116) in kaon electroproduction
• Progress and Issues in the Electromagnetic Production of Kaon on the Nucleon
• Photon induced K$\Lambda$ production on the proton in the low energy region
• Ridge regression for minimizing the couplings of hyperon resonances in the $K^{+}\Lambda$ photoproduction
• First Measurement of ${\Xi }^{-}$ Polarization in Photoproduction