HADES collaboration (114 authors)Blanco, A.Bordalo, P.Fonte, P.Franco, C.Lopes, L.Mangiarotti, A.Ramos, S.Silva, L.2019-02-042019-02-042018-03-10http://dx.doi.org/10.1016/j.physletb.2018.01.048http://hdl.handle.net/10400.26/27313We present data on charged kaons (K+-) and {\phi} mesons in Au(1.23A GeV)+Au collisions. It is the first simultaneous measurement of K and {\phi} mesons in central heavy-ion collisions below a kinetic beam energy of 10A GeV. The {\phi}/K- multiplicity ratio is found to be surprisingly high with a value of 0.52 +- 0.16 and shows no dependence on the centrality of the collision. Consequently, the different slopes of the K+ and K- transverse-mass spectra can be explained solely by feed- down, which substantially softens the spectra of K- mesons. Hence, in contrast to the commonly adapted argumentation in literature, the different slopes do not necessarily imply diverging freeze- out temperatures of K+ and K- mesons caused by different couplings to baryons.engjournal article2019-02-04