Bonn 2010 – wissenschaftliches Programm
HK 17.8: Vortrag
Dienstag, 16. März 2010, 15:45–16:00, HG IV
Atomic target mass dependence of φ-meson production in proton-nucleus collisions — •Andrey Polyanskiy — Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich
The modification of the vector meson properties in a strongly interacting environment is currently a hot subject in terms of spontaneous chiral symmetry breaking and partial restoration of this symmetry in nuclear matter. The dropping of the vector-meson mass by about 20% has been predicted already at normal nuclear density. However, according to theoretical investigations the φ-meson mass shift in matter is small and the main medium effect on the φ is a sizable increase of its width up to an order of magnitude compared to the vacuum value of 4.3 MeV/c2. The in-medium width of a meson is related to the imaginary part of the nuclear optical potential which is responsible for the meson absorption in nuclear matter. Therefore, information about the φ-meson width can be obtained by analysing the target mass dependence of the φ-meson production cross sections. An ANKE experiment aimed at the measurement of the φ width in the nuclear matter of normal density in proton-nucleus collisions at maximum COSY energy of 2.83 GeV. The φ-mesons were detected in the K+K− decay channel. The total amount of φ’s collected from carbon, cooper, silver and gold targets is about 20000. In the talk the measured A-dependence of the φ production cross sections will be compared with available theoretical predictions.
Supported by the COSY-FFE program.