Nuclear modification of identified strange particles at moderatepTin Au+Au collisions at at RHIC

We present the measurement of strange baryon and meson production for p T up to 5.0 GeV/ c from Au+Au collisions at RHIC. Using decay topology reconstruction, we are able to identify and measure the production rate of strange baryons and mesons for p T up to 5.0 GeV/ c from different centrality bins. The strange baryon and meson yield per binary collision for p T greater than 2 GeV/ c from central collisions will be presented with respect to that from peripheral collisions. Strange baryons and mesons show a different suppression pattern. The suppression of unidentified charged hadrons and neutral pions at high p T from central Au+Au collisions at RHIC has already been reported by STAR and PHENIX. Theoretical calculations showed that the suppression is consistent with parton energy loss in high density medium created in nuclear collisions at RHIC. Our measurement would, in the same theoretical framework, indicate different dynamical behaviour in energy loss and/or fragmentation leading to strange baryon and meson production in the p T region from 2 to 5 GeV/ c . The measurement of strange baryons and mesons at high p T can probe dynamics of nuclear medium effect on identified particle production in the soft-to-hard transition region.