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We study the production of the doubly strange Ξ baryon in subthreshold p + A collisions using a BUU type transport model. We propose a new mechanism for Ξ creation in a two-step process via hyperon-nucleon collisions. We study the influence of the anisotropy of hyperon production in N + N collisions on the Ξ multiplicity. Applying reasonable assumptions on the unknown elementary cross sections, we are able to reconstruct the Ξ yield observed by the HADES collaboration (GSI, Darmstadt) in subthreshold p+Nb collisions. [ABSTRACT FROM AUTHOR]

The production of [lowercase_phi_synonym]-mesons in collisions of 2.83 GeV protons with C, Cu, Al, and Au targets has been measured with the ANKE magnetic spectrometer at the Cooler Synchrotron COSY. The [lowercase_phi_synonym]-mesons were detected at small angles via their K+K- decay. The measured target mass dependence of the production cross section can be related to the in-medium [lowercase_phi_synonym] width. First comparisons with model calculations suggest a significant broadening of the [lowercase_phi_synonym]-width relative to its vacuum value of 4.3 MeV/c2. [ABSTRACT FROM AUTHOR]

Using optical model calculations it has recently been shown that refractive phenomena from the collective mean field can significantly alter the sizes inferred from two-pion correlations. We demonstrate that such effects can be accounted for in classical calculations if mean field effects are included. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]