K + production in proton and deuteron induced reactions at subthreshold energies

Abstract

Abstract. The production of K § mesons in proton-nucleus and deuteron-nucleus collisions is analyzed with respect to one-step nucleon-nucleon (NN~NAK +), A-nucleon (AN~NAK+) and two-step pion-nucleon (~N~K § A) production channels on the basis of experimental ground state momentum distributions and free on-shell production processes. Whereas for K § production in proton-nucleus reactions the secondary channel ~N clearly dominates at subthreshold energies, meson and nucleon induced channels are of similar magnitude in deuteron-nucleus reactions. Contrary to nucleus-nucleus collisions the A induced reaction channels are found to be of minor importance. The experimental differentiation of the underlying microscopic reaction channels appears possible via differential proton K § coincidence measurements as shown in detail by the microscopic simulations including proton rescattering.

Kaon versus antikaon production at SIS energies

“…Another uncertainty in our analysis, i.e. the behaviour of the ∆N production cross sections, can be eliminated by performing studies for K + and K − production in proton-nucleus reactions, where the ∆-excitation plays a minor role [59]. [41].…”

?-Hypernucleus formation in proton-nucleus reactions

“…Here, we investigate the production of heavy hypernuclei by means of proton + nucleus reactions. In fact, the recent studies on the (p, K +) reaction confirm a quite substantial production of associated A hyperons [19]. Furthermore, also (re +, K +) associated strangeness production reactions have been found effective in creating A hypernuclei [7,9] where A rescattering is expected to play a major role [20].…”

“…The Lorentz invariant differential production cross sections EA,dCrNN-,A+x/d3pA,(x/-S) for the two-nucleon induced channel and EA,dO-~N-~/+X / d3pA,(x/-s) for the pion-nucleon production channel are taken from [19]. Here, (EA, , PA') denotes the fourvector of the A hyperon in the hadron-hadron centerof-mass system.…”

Fermi Motion and Nuclear Modification Factor

“…In the present paper we shall also consider a simple Gaussian parametrization of the momentum distribution of nucleons in 12 C nucleus from Ref. [19]. While the first seems more adequate for heavy nuclei, the latter may be representative for light nuclei.…”

“…of the order of the nuclear Fermi momentum. At intermediate energies the inclusion of momentum distributions in nuclei quantifying the nucleon motion is crucial for the production of kaons [15,19,17], eta mesons [18] and antiprotons [16] in p+A collisions. It is well known that at subthreshold and near-to-threshold collisions the Fermi motion leads to a huge enhancement of hadron production cross sections based on the first collision model.…”