6 - Applications in deep inelastic scattering
Summary
The preceding chapters have established the theoretical framework which ought to describe the perturbative scattering of strongly interacting particles at high centre-of-mass energies (in the Regge region). In this chapter (and the next), we shall attempt to place this framework under the experimental spotlight. That is to say, we shall turn the theoretical calculations of the preceding chapters into physical cross-sections for processes which can be measured at present or future colliders.
To construct these cross-sections, we need to specify the impact factors which define the coupling of the Pomeron to the external particles. These impact factors are then convoluted with the universal BFKL amplitude, f(ω, k1, k2, q) (see Eq.(4.33)) in order to obtain the relevant elastic-scattering amplitude. Remember that we are using perturbation theory and so can take our result seriously only if we are sure that the typical transverse momenta are much larger than ΛQCD. AS we showed in Section 5.1, for t = 0 the largeness of the typical transverse momenta is assured provided we pick processes with impact factors which are peaked at large transverse momenta. Clearly, this is not the case for proton–proton scattering and that is why we were not surprised to find that our results were incompatible with the relatively modest rise of the p–p total cross-section with increasing s. Another way of keeping our integrals away from the infra-red region is to work at high-t but we defer this topic until the next chapter.
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- Quantum Chromodynamics and the Pomeron , pp. 139 - 174Publisher: Cambridge University PressPrint publication year: 1997