Improvement and Taste Symmetry Breaking for Staggered Quarks
  We compare several improved actions for staggered quarks. We study the effect of improvement on the taste changing interactions by calculating the splitting in the pion spectrum. We investigate the effect of the improvement on some topological properties. 
E. Follana, C. Davies, A. Hart, P. Lepage, Q. Mason, H. Trottier   (HPQCD and UKQCD collaborations.)