Sub-threshold phi-meson yield in central 58Ni+58Ni collisions

Abstract

The $\varphi$-meson production cross section is measured for the first time at a sub-threshold energy of 1.93 AGeV in \nuc{58}{Ni}+\nuc{58}{Ni} central collisions. The $\varphi$ data were obtained within the acceptance of the CDC/Barrel subsystem of FOPI. For a sample of $4.7\cdot 10^6$ central events, after background subtraction, 23 candidates were observed. Extensive GEANT simulations of the detector performance are shown in a thorough comparison to the real response, aiming at a good understanding of the apparatus and at a trustable determination of the efficiencies, production probability and possible systematic errors. A filter procedure is elaborated, which is meant to facilitate the comparison of any theoretical calculation or new data with the current ones. How to extrapolate the present value to a $\varphi$-meson cross section in $4\pi$ is also discussed. This result on pseudo-vector mesons can now be compared to existing experimental knowledge for the same reaction at the same incident energy for various outgoing channels, $K^{+}$ and $K^{-}$ included. A significant fraction (at least 20%) of the $K^{-}$-mesons is originating in the decay of the $\varphi$, supporting the statement that the two channels are strongly correlated.

48 pages, 10 figures submitted to Nucl.-Phys. A Minor wording corrections, a small inconsistency has been corrected in sect.3.3

References in corpus (4)

• Direct comparison of phase-space distributions of K- and K+ mesons in heavy-ion collisions at SIS energies - evidence for in-medium modifications of kaons ?
• Subthreshold phi-meson production in heavy-ion collisions
• phi puzzle in heavy-ion collisions at 2 AGeV: how many K-from phi decays?
• Production of phi mesons in subthreshold heavy-ion collisions

Cited by in corpus (12)

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• Strange meson production in Al+Al collisions at 1.9A GeV
• Role of phi decays for K- yields in relativistic heavy-ion collisions
• Centrality dependence of subthreshold $\varphi$ meson production in Ni+Ni collisions at 1.9A GeV
• Catalytic phi meson production in heavy-ion collisions
• Catalytic Reactions in Heavy-ion Collisions
• Determination of the $\varphi$-meson production process and its absorption cross section via directed flow
• Results on strangeness production from HADES