Azimuthal emission pattern of K+ and K− at SIS energies

The Kaos Collaboration has been investigating the production of kaons and antikaons in Au+Au and Ni+Ni collisions at beam energies between 1 and 2 A⋅GeV as a function of the collision centrality, the particle energy and the emission angles. The anisotropy of the azimuthal emission pattern of K+ mesons provides evidence for a repulsive kaon-nucleon potential in the nuclear medium. New information on the in-medium potentials of antikaons is expected from the measurement of their azimuthal angle distributions.