Antikaon production in nucleon- nucleon reactions near threshold

Abstract

The antikaon production cross section from nucleon-nucleon reactions near threshold is studied in a meson exchange model. We include both pion and kaon exchange, but neglect the interference between the amplitudes. In case of pion exchange the antikaon production cross section can be expressed in terms of the antikaon production cross section from a pion-nucleon interaction, which we take from the experimental data if available. Otherwise, a K * -resonance exchange model is introduced to relate the different reaction cross sections. In case of kaon exchange the antikaon production cross section is related to the elastic KN andKN cross sections, which are again taken from experimental measurements. We find that the one-meson exchange model gives a satisfactory fit to the available data for the N N → N N KK cross section at high energies. We compare our predictions for the cross section near threshold with an earlier empirical parameterization and that from phase space models.

Production of a0 mesons in pp and pn reactions

“…dashed line from Ref. [48]). Moreover, the ELM calculations are higher than the Regge model predictions which indicates, that the ELM amplitudes at high energies have to be reggeized or unitarized.…”

“…Q ≃ 1 GeV. [48]. Lower part: the calculated total cross section (within parameter set 1) for the reaction pp → ppa 0 0 → ppK + K − as a function of Q = √ s − √ s 0 in comparison to the experimental data.…”

Kaon and Phi Production in Pion-Nucleus Reactions at 1.7 GeV/c

“…Accordingly, the double ratio extracted on the basis of the cross-section parametrization adapted from Sibirtsev et al [9] and the one implemented GiBUU where averaged leading to a value of K − /K + (W)/K − /K + (C) = 0.948 ± 0.092. The measured double ratio of K − /K + (W)/K − /K + (C) = 0.442 ± (0.03) stat ± +0.07 −0.04 sys is well below the reference directly indicating K − absorption in the heavy target Tungsten with respect to Carbon.…”

“…1. As not all cross-sections have been measured at the presented beam momentum, a cross-section parametrization proposed by Sibirtsev et al [9] has been adapted to extracted the cross-section for each individual channel at p π − = 1.7 GeV/c. It reads as follows:…”

“…The red solid curve indicates the fit corresponding to a cross-section parametrization adapted from Sibirtsev et al [9], while the yellow solid curve pictures the parametrization employed in GiBUU [12]. The blue dashed lines represent the suggested cross-section by the fit at p π − = 1.7 GeV/c.…”