Measurement of $K^{\ast }(892{)}^0$ and $K^0$ mesons in Al+Al collisions at 1.9$A$ GeV

Abstract

New measurement of sub-threshold $K^{\ast }(892{)}^0$ and $K^0$ production is presented. The experimental data complete the measurement of strange particles produced in Al+Al collisions at 1.9$A$ GeV measured with the FOPI detector at SIS/GSI. The $K^{\ast }(892{)}^0$ / $K^0$ yield ratio is found to be $0.0315\pm 0.006(stat.)\pm 0.012(syst.)$ and is in good agreement with the UrQMD model prediction. These measurements provide information on in-medium cross section of $K^{+}$ - $\ddot{I}{€}^{-}$ fusion which is the dominant process on sub-threshold $K^{\ast }(892{)}^0$ production.

5 pages, 4 figures, accepted for publication in Phys. Rev. C