A model for soft high-energy scattering: Tensor pomeron and vector odderon

Abstract

A model for soft high-energy scattering is developed. The model is formulated in terms of effective propagators and vertices for the exchange objects: the pomeron, the odderon, and the reggeons. The vertices are required to respect standard rules of QFT. The propagators are constructed taking into account the crossing properties of amplitudes in QFT and the power-law ansätze from the Regge model. We propose to describe the pomeron as an effective spin 2 exchange. This tensor pomeron gives, at high energies, the same results for the pp and pp elastic amplitudes as the standard Donnachie-Landshoff pomeron. But with our tensor pomeron it is much more natural to write down effective vertices of all kinds which respect the rules of QFT. This is particularly clear for the coupling of the pomeron to particles carrying spin, for instance vector mesons. We describe the odderon as an effective vector exchange. We emphasise that with a tensor pomeron and a vector odderon the corresponding charge-conjugation relations are automatically fulfilled. We compare the model to some experimental data, in particular to data for the total cross sections, in order to determine the model parameters. The model should provide a starting point for a general framework for describing soft highenergy reactions. It should give to experimentalists an easily manageable tool for calculating amplitudes for such reactions and for obtaining predictions which can be compared in detail with data.

Introduction to the physics of the total cross section at LHC

“…Phenomenologically, the one-to-one correspondence between the asymptotic total cross section and the Pomeron trajectory, made the Pomeron go from a fixed pole (α P = 1) at low energies, to a moving pole with intercept larger than one, to justify the rising cross section observed at the ISR. As for the C = −1 possible partner of the Pomeron, it is called an Odderon, but it is an object so far only seen clearly in theoretical papers, as recently quibbed in [195]. The Odderon is also a QCD effect, and its trajectory so far seems to correspond to a constant α O = 1.…”

“…In [195], a model for soft high-energy scattering, which includes a tensor Pomeron and vector Odderon has appeared with detailed description of Feynman-type rules for effective propagators and vertices.…”

Hadronic total cross sections at high energy and the QCD spectrum

“…(4.36) that in the limit of large b the contribution 22 We note in passing that a Pomeron of gluonic nature and effectively of spin 2 has been recently proposed in ref. [85]. 23 Since the Ω ± baryon does not satisfy the selection rules on baryon number, electric charge and strangeness, the above-mentioned (hypothetical) suppression mechanism would make this value into an upper bound.…”

Central Exclusive Production of Pion Pairs in Proton--(anti)Proton Collisions

“…The exclusive production of lower mass scalar and pseudoscalar resonances within a tensor pomeron approach [12] was examined recently in [14].…”

“…There the effective vertices and propagators have been taken from Refs. [12] and [13]. The coupling parameters of tensor Regge exchanges are fixed based on the HERA data for the γp → ρ 0 p reaction.…”