Can we distinguish energy loss from hadron absoprtion?
  Knowing whether a hadron is formed inside or outside the nuclear medium is very important for correctly interpreting jet quenching in heavy-ion collisions. The cleanest experimental environment to study the space-time evolution of hadronization is semi-inclusive DIS on nuclear targets. Two frameworks are presently competing to explain the observed attenuation of hadron production: quark energy loss, with hadron formation outside the nucleus, and nuclear absorption with hadronization starting inside the nucleus. I demonstrate that the observed approximate A^(2/3) scaling of experimental data cannot conclusively establish the correctness of either energy loss or absorption. 
Alberto Accardi