Short-range repulsion and isospin dependence in the KN system

The short-range properties of the KN interaction are studied within the meson-exchange model of the Juelich group. Specifically, dynamical explanations for the phenomenological short-range repulsion, required in this model for achieving agreement with the empirical KN data, are explored. Evidence is found that contributions from the exchange of a heavy scalar-isovector meson (a_0(980)) as well as from genuine quark-gluon exchange processes are needed. Taking both mechanisms into account a satisfactory description of the KN phase shifts can be obtained without resorting to phenomenological pieces.Comment: 26 pages, 5 figure

Die Pionproduktion bei der Kaon-Nukleon Wechselwirkung beschrieben im Mesonenaustauschbild

Recently we have presented in our group a meson exchange model for the K$^{+}$ N interaction below pion treshold which contains apart from single-meson exchange, higher-order diagrams involving $\Delta$K,NK* and $\Delta$K* intermediate states. We now extend this model above pion treshold i.) by taking into account the K*- and $\Delta$-width, calculated in a generalized Lee model; ii.) by doing a full coupled-channel calculation, under inclusion of the diagonal $\Delta$K and NK* interaction based likewise on meson exchange. It turns out that the latter interaction as well as the off-shell behavior of the widths are essential for reproducing the pion production data in both isospin channels

Die Pionproduktion bei der Kaon-Nukleon Wechselwirkung beschrieben im Mesonenaustauschbild

Recently we have presented in our group a meson exchange model for the K+N interaction below pion threshold which contains apart from single-meson exchange, higher-order diagrams involving #DELTA#K,NK"* and #DELTA#K"* intermediate states. We now extend this model above pion threshold i.) by taking into account the K"*- and #DELTA#-width, calculated in a generalized Lee model, ii.) by doing a full coupled-channel calculation, under inclusion of the diagonal #DELTA#K and NK"* interaction based likewise on meson exchange. It turns out that the latter interaction as well as the off-shell behaviour of the widths are essential for reproducting the pion production data in both isospin channels. (orig.)In der vorliegenden Arbeit stellen wir ein Mesonenaustauschmodell zur Beschreibung der Ein-Pionproduktion bei der KN Wechselwirkung vor. Die Pionproduktion bei der KN Wechselwirkung wird ueberwiegend durch die Zerfaelle des #DELTA# #-># N#pi# und des K"* #-># K#pi# bestimmt. Wir erzielten eine gute Beschreibung der Pionproduktionsdaten, nachdem wir die direkten Austauschbeitraege K#DELTA# #-># K#DELTA# bzw. K*N* #-># K"*N in einer Drei-Kanal-Rechnung beruecksichtigt haben. Dies gilt sowohl fuer den Anstiegsbereich als auch fuer die Struktur der inelastischen Wirkungsquerschnitte. Ohne diese direkten Wechselwirkungen - also nur durch Mitnahme der Boxbeitraege KN #-># K#DELTA# #-># KN und KN #-># K"*N #-># KN -ist eine vollstaendige Beschreibung der Pionproduktionsdaten nicht moeglich. (orig.)Available from TIB Hannover: RA 831(2701) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Elastische K+-Kern-Streuung mit einer mikroskopischen K+-Nukleon t-Matrix

Copy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman