paper

Strangeness Excitation Functions and Transition from Baryonic to Mesonic Freeze-Out

arXiv:0911.0526

Abstract

The sharp peak in the K+/pi+ ratio in relativistic heavy-ion collisions is discussed in the framework of the Statistical Model. In this model a rapid change is expected as the hadronic gas undergoes a transition from a baryon-dominated to a meson-dominated gas. The maximum in the Lambda/Ï $r a t i o i s w e l l r e p r o d u ce d b y t h e S t a t i s t i c a l M o d e l, b u tt h ec han g e in t h eK + / p i + r a t i o i sso m e w ha tl ess p r o n o u n ce d t han t h eo n eo b ser v e d b y t h e N A 49 co l l ab or a t i o n . T h ec a l c u l a t e d s m oo t hin cr e a seo f t h eK - / p i r a t i o an d t h es ha p eo f t h e X i - / p i + an d O m e g a - / p i + r a t i ose x hibi t in g ma x imaa t d i f f er e n t in c i d e n t e n er g i es i sco n s i s t e n tw i t h t h e p r ese n tl y a v ai l ab l ee x p er im e n t a l d a t a . W eco n c l u d e t ha tt h e m e a s u r e d p a r t i c l er a t i os w i t h$ 20-30%$ deviations agree with a hadronic freeze-out scenario. These deviations seem to occur just in the transition from baryon-dominated to meson-dominated freeze-out.

7 pages, 5 figures