Theory of the electromagnetic production of hyperons

Abstract

Some basic properties of isobar models are discussed using the Saclay-Lyon, Kaon-MAID, and H2 models and a comparison of their predictions with experimental data is given for photo- and electroproduction of $K^+$ on the proton and for photoproduction of $K^0$ on the deuteron in specific kinematical regions. Results of the isobar models are also compared with the Regge-isobar hybrid model, Regge-plus-resonance.Comment: 13 pages, 6 figures; in Proceedings of the International Conference on Hypernuclear and Strange Particle Physics (HYP2012), 1 - 5 October, 2012, Barcelon

Photoproduction of K+Λ within a Regge-plus-resonance model

“…An overview of N * 's included in various recent models. Our current RPR-BS models are compared with our older RPR-1 and RPR-2 models [38], with the Ghent RPR-2011 model and also with our recent isobar models BS1 [11], BS2 [11], and BS3 [12].…”

“…Angular dependence of the cross section calculated with RPR-BS (solid line), RPR-BS with pseudovector coupling in the KΛN vertex (dashed line), RPR-1[38] (dotted line), RPR-2[38] (dashed double-dotted line), and RPR-2011[25] (dashdotted line) are shown for six values of the center-of-mass energy. The data stem from the CLAS 2005[30] and CLAS 2010[29] collaborations.…”

High-resolution hypernuclear spectroscopy at Jefferson Lab, Hall A

“…Due to the strong damping of the hypernuclear production cross section by the nucleushypernucleus form factors for large kaon angles, the dominant contribution from the elementary amplitudes comes from the region of very small kaon angles. In this kinematical region, however, the various isobar models give big differences in predicted cross sections, especially for E lab γ > 1.7 GeV [26,28,29], see also Sect. V A.…”

“…Note that no hadronic form factors in the nonresonant part are needed. The different description of the nonresonant part is the main difference between the isobar and RPR models which is important for very small kaon angles [28,40], see also Sect. V A.…”

$$K^{+}\Lambda $$ photoproduction at forward angles and low momentum transfer

“…This has led to a poor understanding of the dynamics of the Born terms and t-channel K + and K * exchanges which dominate at forward angles (see for example Ref. [40]). PWA solutions have also included different s-channel resonance contributions, depending if the fits used the SAPHIR or CLAS datasets (see for example ref.…”