6 units.

Diffraction dissociation in hadron-hadron scattering
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Single diffraction dissociation, illustrated in Fig.2, is given by

$$x_P{d\sigma_{SD}\over dx_Pdt}\ =\ x^{2(1-\alpha_P(t))}f(M_x^2)\eqno(2.6)$$

is terms of soft pomeron exchange. Integrating (2.6) over  t and over $x_P\leq 0.05,$ but excluding the proton state $M_x = M_p,$ one gets a single diffractive cross section $\sigma_{SD}.$ From the Regge formalism one expects $\sigma_{SD}$ to grow with $s$  as $s^{2\epsilon},$ but this is not seen in the data as illustrated in Fig.3, which is a simplified version of the more complete plot in Ref.5 where detailed data points are shown. A factor of 2 is included in Fig.3 to account for single diffractive dissociation of either of the colliding protons (antiproton). At Fermilab collider energies there is a discrepancy of an order of magnitude between the Regge fit and the data.

It seems clear that this discrepancy and the slow growth of $\sigma_{SD}$ with energy signal a breakdown of the Regge analysis when ${\sqrt{s}}\geq 20
GeV.$ I think this breakdown can be expressed in various equivalent ways. (i) A low energies inelastic collisions induce, through unitarity, both elastic scattering and diffractive dissociation. However, as $S(b)$ goes to zero for small and moderate $b$ at high energies, 