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Pion-kaon correlation functions are constructed from central Au+Au STAR data taken at sqrt[s(NN)]=130 GeV by the STAR detector at the Relativistic Heavy Ion Collider (RHIC). The results suggest that pions and kaons are not emitted at the same average space-time point. Space-momentum correlations, i.e., transverse flow, lead to a space-time emission asymmetry of pions and kaons that is consistent with the data. This result provides new independent evidence that the system created at RHIC undergoes a collective transverse expansion.

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We present the first measurement of midrapidity vector meson production in AuϩAu collisions at RHIC (ͱs NN ϭ130 GeV) from the STAR detector. For the 11% highest multiplicity collisions, the slope parameter from an exponential fit to the transverse mass distribution is Tϭ379Ϯ50(stat)Ϯ45(syst) MeV, the yield dN/dyϭ5.73Ϯ0.37(stat)Ϯ0.69(syst) per event, and the ratio N /N h Ϫ is found to be 0.021Ϯ0.001(stat) Ϯ0.004(syst). The measured ratio N /N h Ϫ and T for the meson at midrapidity do not change for the selected multiplicity bins.

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Nuclei of 7 Li were accelerated at the JINR Nuclotron. After the charge-exchange reaction involving these nuclei at an external target a second 7 Be beam of energy 1.23A GeV was formed.This beam was used to expose photo-emulsion chambers. The mean free path for inelastic 7 Be interactions in emulsion λ=14.0±0.8 cm coincides within the errors with those for 6 Li and 7 Li nuclei.More than 10% of the 7 Be events are associated with the peripheral interactions in which the total charge of the relativistic fragments is equal to the charge of the 7 Be and in which charged mesons are not produced. An unusual ratio of the isotopes is revealed in the composition of the doubly charged 7 Be fragments: the number of 3 He fragments is twice as large as that of 4 He fragments.In 50% of peripheral interactions, a 7 Be nucleus decays to two doubly charged fragments. The present paper gives the channels of the 7 Be fragmentation to charged fragments. In 50% of events, the 7 Be fragmentation proceeds only to charged fragments involving no emission of neutrons. Of them, the 3 He+ 4 He channel dominates, the 4 He+d+p and 6 Li+p channels constitute 10% each.Two events involving no emission of neutrons are registered in the 3-body 3 He+t+p and 3 He+d+d channels. The mean free path for the coherent dissociation of relativistic 7 Be nuclei to 3 He+ 4 He is 7±1 m. The particular features of the relativistic 7 Be fragmentation in such peripheral interactions are explained by the 3 He+ 4 He 2-cluster structure of the 7 Be nucleus.PACS numbers: 21.45.+v, 23.60+e, 25.10.+s *

The results of investigations of the relativistic 9 Be nucleus fragmentation in emulsion which entails the production of two He fragments of an energy of 1.2 A GeV are presented. The results of the angular measurements of the 9 Be→2He events are analyzed. The 9 Be→ 8 Be+n fragmentation channel involving the 8 Be decay from the ground (0 + ) and the first excited (2 + ) states to two α particles is observed to be predominant.