A.K. Holme

Strangeness enhancement at mid-rapidity in Pb Pb collisions at 158-A-GeV/c

We study the influence of lexical subsumption on the semantic proximity of terms. By studying the semantic relation between lexically subsumed terms in an existing controlled vocabulary and those in a corpus, we formulate hypotheses on the underlying specific relations. These hypotheses enable us to propose an ordering of term variants found in the corpus, by probability of decreasing semantic proximity. Results from our experiment show that surface indices like the presence of proper names, compounds and the number of added words in a term variant are criteria for ordering the variants of the same term. The ranking obtained will enable us to form more semantically-cohesive clusters. Applications targeted are text mining, question-answering and science and technology watch.

Enhancement of hyperon production at central rapidity in 158 A GeV/c Pb–Pb collisions

Results are presented on hyperon and antihyperon production in Pb–Pb, pPb and pBe collisions at 158 GeV/c per nucleon. Λ, Ξ and Ω yields have been measured at central rapidity and medium transverse momentum as functions of the centrality of the collision. Comparing the yields in Pb–Pb to those in pBe interactions, strangeness enhancement is observed. The enhancement increases with the centrality and with the strangeness content of the hyperons, reaching a factor of about 20 for the Ω in the central Pb–Pb collisions.

Energy dependence of hyperon production in nucleus–nucleus collisions at SPS

A measurement of strange baryon and antibaryon production in Pb-Pb collisions has been carried out by the NA57 experiment at the CERN SPS, with 40 and 158 A GeV/c beam momentum. Results on

Production of strange and multistrange hadrons in nucleus—nucleus collisions at the SPS

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Strangeness enhancements at central rapidity in 40 A GeV/c Pb-Pb collisions

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Transverse mass spectra of strange and multi–strange particles in Pb–Pb collisions at 158 A GeV/c

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Central-to-peripheral nuclear modification factors in Pb-Pb collisions at √sNN = 17.3 GeV

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Centrality dependence of the expansion dynamics in Pb Pb collisions at 158-A-GeV/c

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Study of the transverse mass spectra of strange particles in Pb–Pb collisions at 158 A GeV/c

hyperon yields at mid-rapidity in the most central 53% of Pb-Pb collisions at 40 A GeV/c are presented and compared with those obtained at higher energy, in the same collision centrality range. The

Determination of the event centrality in the WA97 and NA57 experiments

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