Isospin Diffusion in Heavy Ion Reactions

11 pages, 3 figuresUsing symmetric 112Sn+112Sn, 124Sn+124Sn collisions as references, we probe isospin diffusion in peripheral asymmetric 112Sn+124Sn, 124Sn+112Sn systems at incident energy of E/A=50 MeV. Isoscaling analyses imply that the quasi-projectile and quasi-target in these collisions do not achieve isospin equilibrium, permitting an assessment of the isospin transport rates. We find that comparisons between isospin sensitive experimental and theoretical observables, using suitably chosen scaled ratios, permit investigation of the density dependence of the asymmetry term of the nuclear equation of state