Diffraction at the LHC

Understand

We show that the diffractive pp (and p\bar{p}) data (on \sigma_tot, d\sigma_el/dt, proton dissociation into low-mass systems, \sigma^D(low M), and high-mass dissociation, d\sigma/d(\Delta\eta)) in a wide energy range from CERN-ISR to LHC energies, may be described in a two-channel eikonal model with only one `effective' pomeron.

• By allowing the pomeron coupling to the diffractive eigenstates to depend on the collider energy (as is expected theoretically) we are able to explain the low value of \sigma^D(low M) measured at the LHC.
• We calculate the survival probability, S^2, of a rapidity gap to survive `soft rescattering'.
• We emphasize that the values found for S^2 are particularly sensitive to the detailed structure of the diffractive eigenstates.