On stable commutator lengths of Dehn twists along separating curves
  We give new upper bounds on the stable commutator lengths of Dehn twists along separating curves in the mapping class group of a closed oriented surface. The estimates of these upper bounds are $O(1/g)$, where $g$ is the genus of the surface. 
Naoyuki Monden, Kazuya Yoshihara
math.GT math.GR