The extraction of the bare triple-pomeron vertex; a crucial ingredient for diffraction

Abstract: The triple-pomeron coupling lies at the heart of the predictions for high energy diffractive processes. We explain why the existing determinations, which use single-particle inclusive hadronic data , underestimate the value of the bare coupling, due to the neglect of soft rescattering which populates the rapidity gaps. We describe how data for the process can be used to give a much more reliable estimate of the bare coupling. We use the existing, fragmentary, data from HERA to show that the triple-pomeron coupling is probably about 3 times larger than the previous determinations. We emphasize the importance of an explicit measurement of the mass spectrum of the Y system which accompanies production at HERA. The consequences for ultra high energy cosmic ray showers are mentioned. [Copyright &y& Elsevier]