Survival Probability of Large Rapidity Gaps

We summarize the discussions on the value of the survival probabilities of the large rapidity gap ( LRG ) processes at Durham WS’98. 1) Email: [email protected] . 2) Email: [email protected]. 3) Email: [email protected] 1. When we calculate the cross sections with the LRG such as the diffractive (double diffractive (DD)) processes or two jets production with the LRG between them, we have to estimate the probability that rapidity gap corresponding to the Pomeron exchange will not be filled by secondaries from the scattering of a spectator partons or from the decay of bremsstrahlung gluons. This survival probability < S > < 1 depends on the kinematics of each specific process and may violate the factorization (even for the cases where the factorization properties of diffractive amplitudes are satisfied at the initial stage). 2. To demonstrate the role of bremsstrahlung emission let us consider the exclusive Higgs boson DD production pp → p + [LRG] + H + [LRG] + p (1) where the heavy boson H is bounded by two rapidity gaps [1]. We start from the simplest Low-Nussinov (two gluon exchange) model for the Pomeron. The Higgs boson is produced in the central rapidity region by the gluon-gluon fusion (gg → H) whilst a second t-channel gluon is needed to screen the colour flow. The amplitude is proportional to the integral over the gluon transverse momentum qt