Probabilities of rapidity gaps in high energy interactions

Abstract

We show that high energy hadronic reactions which contain a rapidity gap and a hard subprocess have a specific dependence on the kinematic variables, which results in a characteristic behaviour of the survival probability of the gap. We incorporate this mechanism in a two-channel eikonal model to make an essentially parameter-free estimate of diffractive dijet production at the Tevatron, given the diffractive structure functions measured at HERA. The estimates are in surprising agreement with the measurements of the CDF collaboration. We briefly discuss the application of the model to other hard processes with rapidity gaps.Comment: 18 pages, 5 figures, Late

Prospects for new physics observations in diffractive processes at the LHC and Tevatron

“…In practice, we calculate the effects using a two-channel eikonal. As a consequence (6) does not have a factorized form, andŜ 2 should be viewed as the soft survival probability appropriately averaged over the channels [3,4]. The value of the survival factorŜ 2 depends on the particular double-diffractive production mechanism, and may be a function of y and M 2 .…”

“…Moreover partons of larger k ti tend to have large momentum fractions x i , see (20). For partons of relatively large x i we sample mainly the smaller size component of the proton wave function, which in turn has the smaller absorption cross section [4]. This leads to a larger 'soft' survival probabilityŜ 2 .…”

Photon-exchange processes at hadron colliders as a probe of the dynamics of diffraction

“…in a clean environment (see for example, [1] and references therein) and (ii) to study the properties of the diffractive amplitude. Unfortunately, the cross sections for such processes are suppressed by the small probability,Ŝ 2 , that the rapidity gaps survive soft rescattering effects between the interacting hadrons, which can generate secondary particles populating the gaps [2]- [9].…”

“…Here M i (s, b 2 t ) are the amplitudes (in impact parameter b t space) of the process of interest at centre-of-mass energy √ s. They may be different for the different diffractive eigenstates. It is important to note that the suppression factorŜ 2 is not universal, but depends on the particular hard subprocess, as well as on the kinematical configurations of the parent reaction [9].…”

“…The opacities Ω i (s, b t ) of the proton have been calculated in a number of models [12,10,11,8,9], and used to determineŜ 2 for various rapidity gap processes. However it is difficult to guarantee the precision of predictions which rely on soft physics.…”