1. Free Quarks and Antiquarks versus Hadronic Matter Xiao-Ming Xu Collaborator: Ru Peng

2. Picture below T c Critical temperature T c : transition between quark gluon plasma and hadronic matter Hadronic matter below T c : scatterings and flow of hadrons π, ρ, K, K *,…

3. We propose new form of matter below T c : free quarks, free antiquarks and hadrons

4. F. Karsch, et al., Nucl. Phys. B605, 579 (2001)

5. Medium effect Lattice QCD calculations give temperature-dependent quark-quark potential. Medium screening leads to weak binding of quarks. When temperature increases, the confinement potential gets weak and the bound state gets loose.

6. We expect Meson-meson collisions in high-temperature hadronic matter produce free quarks and antiquarks easily.

7. Cross Section meson-meson reaction

8. quark-quark potential Transition amplitude M fi is derived from quark-antiquark wave functions and the quark-quark potential b(T)=0.35[1-(T/T c ) 2 ]  (T c -T)  (T)=0.28  (T c -T) T c =0.175 GeV, d=0.897 GeV m u =m d =0.334 GeV, m s =0.575 GeV C.-Y. Wong, Phys. Rev. C65, 034902 (2002)

9. unpolarized cross section (1) L A =L B =0 (2) L A =0, L B  0, S A =0 (3) L A =0, L B =1, S A =1, S B =1

10. master rate equation time evolution of number densities of , , K and K* in static hadronic matter

14. Ratios of number densities number density of hadronic matter n H  n  +n  +n K +n K*  Critical temperature T c =0.175 GeV T (GeV) n q /n H at time t=0.5 fm/c 0.174 0.87 in the chiral limit 0.174 0.33 with the constituent quark mass 0.16 0.11 0.15 0.05 0.14 0.02

15. SUMMARY We have found: a.an appreciable amount of free quarks and antiquarks produced by meson-meson reactions b. a new mechanism for deconfinement of quarks and antiquarks at high temperature. c.new form of matter below T c : free quarks, free antiquarks and hadrons. arXiv:0708.3804