Wide acceptance measurement of the K${}^{-}$/K${}^{+}$ ratio from Ni+Ni collisions at 1.91A GeV

Abstract

The FOPI Collaboration at the GSI SIS-18 synchrotron measured charged kaons from central and semi-central collisions of Ni+Ni at a beam energy of 1.91A GeV. We present the distribution of the K${}^{-}$\K${}^{+}$ ratio on the energy vs polar angle plane in the nucleon-nucleon center-of-mass frame, with and without subtraction of the contribution of $\varphi$(1020) meson decays to the K${}^{-}$ yield. The acceptance of the current experiment is substantially wider compared to the previous measurement of the same colliding system. The ratio of K${}^{-}$ to K${}^{+}$ energy spectra is expected to be sensitive to the in-medium modifications of basic kaon properties like mass. Recent results obtained by the HADES Collaboration at 1.23A and 1.76A GeV indicate that after inclusion of the $\varphi$ meson decay contribution to the K${}^{-}$ production no difference between the slopes of the K${}^{-}$ and K${}^{+}$ energy spectra is observed within uncertainties. For our data a linear fit to this ratio obtained after subtraction of the $\varphi$ meson contribution still shows a decrease with kinetic energy, although a constant value cannot be rejected. The contribution of $\Lambda (1520)\to p{\text{K}}^{-}$ decays estimated from fitting the thermal model to the experimental yields appears to be another factor of moderate relevance.

arXiv comment8 pages, 4 figures, 2 tables (1 appendix table)

References in corpus (25)

• Modelling the many-body dynamics of heavy ion collisions: Present status and future perspective
• Features of particle multiplicities and strangeness production in central heavy ion collisions between 1.7A and 158A GeV/c
• Kaon production in heavy ion reactions at intermediate energies
• THERMUS -- A Thermal Model Package for ROOT
• The properties of \bar{K} in the nuclear medium
• Hadron Production in Ultra-relativistic Nuclear Collisions: Quarkyonic Matter and a Triple Point in the Phase Diagram of QCD
• Strangeness Production close to Threshold in Proton-Nucleus and Heavy-Ion Collisions
• In-medium Production of Kaons at the Mean-Field Level
• Kaon versus Antikaon Production at SIS Energies
• Hyperon production in Ar+KCl collisions at 1.76A GeV
• Phi decay: a relevant source for K- production at SIS energies?
• Kaon flow as a probe of the kaon potential in nuclear medium
• Production of K+ and of K- Mesons in Heavy-Ion Collisions from 0.6 to 2.0 AGeV Incident Energy
• First Measurement of Antikaon Phase-Space Distributions in Nucleus-Nucleus Collisions at Subthreshold Beam Energies
• The antikaon nuclear potential in hot and dense matter
• 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 ?
• Deep sub-threshold ϕ production and implications for the K+/K- freeze-out in Au+Au collisions
• K^0 and Λproduction in Ni + Ni collisions near threshold
• Charged pions from Ni on Ni collisions between 1 and 2 AGeV
• Production of Charged Pions, Kaons and Antikaons in Relativistic C+C and C+Au Collisions
• Azimuthal Emission Patterns of $K^{+}$ and of $K^{-}$ Mesons in Ni + Ni Collisions near the Strangeness Production Threshold
• Influence of $\varphi$ mesons on negative kaons in Ni+Ni collisions at 1.91A GeV beam energy
• Strange meson production in Al+Al collisions at 1.9A GeV
• Chiral symmetry and strangeness at SIS energies
• Centrality dependence of subthreshold $\varphi$ meson production in Ni+Ni collisions at 1.9A GeV

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