Multigap diffraction at CDF
  We present a study of $\bar pp$ collisions with a leading antiptoton and a rapidity gap in addition to that associated with the antiproton. The second gap is either within the region available to the proton dissociation products, $\bar p+p\to (\bar p+gap)+X+gap+Y$, or adjacent to the outgoing proton $\bar p+p\to (\bar p+gap)+X+(gap+p)$. Results are reported for two-gap to one-gap event ratios and compared with one-gap to no-gap ratios and with theoretical expectations. 
Konstantin Goulianos