Deep sub-threshold ϕ production in Au+Au collisions

J Adamczewski-Musch,L Fabbietti,I Fröhlich,S Chernenko,K Lapidus,H Tsertos,C Höhne,M Traxler,P Zumbruch,B Kardan,J Friese,P Fonte,E Epple,J Biernat,S Maurus,T Scheib,C Müntz,S Harabasz,W Przygoda,G Korcyl,E Schwab,O Fateev,V Metag,P Filip,F Scozzi,G Kornakov,M Golubeva,C Wendisch,M Böhmer,B Ramstein,T Kunz,S Ramos,T Karavicheva,L Silva,W Koenig,O Pechenova,M Lorenz,A Lebedev,T Heinz,P Rosier,B Kämpfer,P Sellheim,C Deveaux,H Schuldes,L Lopes,J Stroth,A Belyaev,H Ströbele,V Wagner,L Chlad,M Szala,W Kühn,R Greifenhagen,L Naumann,A Kurilkin,R Lalik,O Svoboda,R Holzmann,E Usenko,C Behnke,L Maier,R Gernhäuser,F Guber,Y Zanevsky,J Michel,A Rost,P Bordalo,Y Parpottas,A Sadovsky,J Wirth,A Blanco,C Blume,S Spataro,F Seck,A Reshetin,C Franco,O Petukhov,T Mahmoud,A Mangiarotti,V Pechenov,J Markert,C Sturm,J Pietraszko,P Strzempek,A Ierusalimov,A Ivashkin,M Gumberidze,A Dybczak,T Galatyuk,O Arnold,T Hennino,A Kurepin,P Salabura,A Belounnas,J Siebenson,J Dreyer,M G Wiebusch ,S Hlaváč ,J C Berger-Chen ,P Rodríguez-Ramos ,P K Kurilkin ,M Pałka ,Robert Helmut Münzer ,D M Mihaylov ,J A Garzón ,B W Kolb ,P Tlustý ,I Köenig ,K Nowakowski ,S V Morozov ,А Куглер ,Yu G Sobolev ,V P Ladygin ,R Kötte

doi:10.1016/j.physletb.2018.01.048

Abstract

We present data on charged kaons (K±) and ϕ mesons in Au(1.23A GeV)+Au collisions. It is the first simultaneous measurement of K− and ϕ mesons in central heavy-ion collisions below a kinetic beam energy of 10A GeV. The ϕ/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.

Highlights

We present data on charged kaons (K±) and φ mesons in Au(1.23A GeV)+Au collisions
The different slopes of the K+ and K− transverse-mass spectra can be explained solely by feeddown, which substantially softens the spectra of K− mesons
In contrast to the commonly adapted argumentation in literature, the different slopes do not necessarily imply diverging freezeout temperatures of K+ and K− mesons caused by different couplings to baryons

Summary

Introduction

We present data on charged kaons (K±) and φ mesons in Au(1.23A GeV)+Au collisions. It is the first simultaneous measurement of K− and φ mesons in central heavy-ion collisions below a kinetic beam energy of 10A GeV. We present data on charged kaons (K±) and φ mesons in Au+Au collisions at a kinetic beam energy of 1.23A GeV.

Results

Conclusion