Interpreting the LSND anomaly: sterile neutrinos or CPT-violation or...?

We first study how sterile neutrinos can fit the 5sigma bar-nu_mu --> bar-nu_e LSND anomaly: 3+1 solutions give a poor fit, but better than than 2+2 solutions (the best fit regions are somewhat different, so that MiniBoone could discriminate). If instead MiniBoone will find no nu_mu --> nu_e signal, we will have a hint for CPT violation. Already now, unlike sterile neutrinos, CPT-violating neutrino masses can nicely accomodate all safe and unsafe data. We study how much CPT must be conserved according to atmospheric and K2K data and list which CPT-violating signals could be discovered by forthcoming solar and long-baseline experiments.