Diffractive dissociation re-visited for predictions at the LHC

Abstract

We describe the formalism, and present the results, for a triple-Regge analysis of the available pp and pp high-energy data which explicitly accounts for absorptive corrections. In particular, we allow for the gap survival probability, S 2 , in single proton diffractive dissociation. Since for pp scattering the value of S 2 is rather small, the triple-Pomeron vertex obtained in this analysis is larger than that obtained in the old analyses where the suppression caused by the absorptive corrections was implicitly included in an effective vertex. We show that the bare triple-Pomeron coupling that we extract from the pp and pp data is consistent with that obtained in a description of the γp → J/ψ + Y HERA data. The analyses of the data prefer a zero slope, corresponding to the small size of the bare vertex, giving the hope of a smooth matching to the perturbative QCD treatment of the triple-Pomeron coupling.

Modelling exclusive meson pair production at hadron colliders

“…In the case of high-mass dissociation, we can expect about a 10 % contribution from secondary Reggeons (using the IP IP IR vertex from [59]), while the remaining 75 % must then be caused by the triple-Pomeron (IP IP IP) term, which is in agreement with the estimates of [59].…”

“…On the other hand, the contributions described by the triple-Reggeon terms have a different structure, and they are not concentrated in the same regions of b t space. First, the size of the IP IP IP and the IP IP IR triple-Reggeon vertices are smaller [59][60][61] than the proton size. This is seen for example, in the H1 measurement of the slope in proton-dissociative events, b pd = 1.79 ± 0.12 GeV −2 [56], which is lower than that in elastic case, for which b el = 4.88 ± 0.15 GeV −2 .…”

The practical Pomeron for high energy proton collimation

“…7a in which a Reggeon or a Pomeron is exchanged between the elastically-scattered proton and the system X . In the limit s M 2 X |t| and M 2 X not too small the process may be described by the triple-Regge model [8,9,[32][33][34] as illustrated in Fig. 7c and discussed in Sect.…”

Elastic and proton-dissociative photoproduction of J/ψ mesons at HERA

“…In contrast, the cross section for elastic J /ψ production, γp → J /ψp, rises more steeply with W γp , δ ≈ 0.7 [4,5], and is thus incompatible with a universal Pomeron hypothesis [2]. The W γp dependence of proton-dissociative J /ψ production [6][7][8] is expected to be similar to the elastic case.…”