[Paper Review] Diffraction: Results and Conclusions

Konstantin Goulianos|ArXiv.org|Jun 16, 1998

X-ray Diffraction in Crystallography5 references7 citations

TL;DR

This paper summarizes experimental results on soft and hard diffraction processes, analyzing data from high-energy hadronic collisions to investigate the nature of the pomeron. It concludes that the pomeron behaves as a trajectory with quantum numbers of the vacuum, supporting a Reggeized gluon picture in QCD, with evidence for a hard pomeron with αP ≈ 1.28.

ABSTRACT

We summarize the main features of available experimental results on soft and hard diffraction and draw conclusions about the nature of the pomeron.

Motivation & Objective

• To synthesize and interpret experimental data on soft and hard diffraction in high-energy hadronic collisions.
• To determine the quantum numbers and trajectory behavior of the pomeron from empirical results.
• To assess whether the pomeron can be described as a Reggeized gluon or a more complex QCD object.
• To evaluate the consistency of the pomeron trajectory with perturbative and non-perturbative QCD expectations.
• To provide a phenomenological conclusion on the nature of the pomeron based on current data.

Proposed method

• Analysis of inclusive and diffractive cross-section measurements from hadron-hadron and lepton-hadron scattering experiments.
• Examination of the energy dependence of diffractive cross sections to extract pomeron trajectory slope.
• Comparison of data with Regge field theory predictions for a pomeron with vacuum quantum numbers.
• Use of the pomeron exchange model to fit data, assuming a trajectory αP(α) = 1 + α' t with α' ≈ 0.25 GeV⁻².
• Application of the factorization hypothesis to separate soft and hard contributions in diffractive processes.
• Evaluation of the hard pomeron contribution via comparison with deep inelastic scattering and Drell-Yan data.

Experimental results

Research questions

• RQ1 What is the energy dependence of diffractive cross sections, and does it support a pomeron trajectory?
• RQ2 Does the pomeron carry vacuum quantum numbers, and is it consistent with a Reggeized gluon?
• RQ3 What is the value of the pomeron slope α' and how does it compare to theoretical expectations?
• RQ4 Can the hard pomeron contribution be isolated and quantified from existing data?
• RQ5 Is the pomeron description consistent across soft and hard diffraction processes?

Key findings

• The pomeron trajectory is consistent with a vacuum quantum number exchange, supporting a Reggeized gluon interpretation.
• The pomeron slope is measured to be α' ≈ 0.25 GeV⁻², with a trajectory intercept αP(0) ≈ 1.28.
• Data from hard diffraction processes show a clear enhancement consistent with pomeron exchange at high momentum transfer.
• The energy dependence of diffractive cross sections follows a power-law behavior compatible with pomeron exchange.
• The hard pomeron contribution is found to be significant in high-energy Drell-Yan and deep inelastic scattering data.
• No evidence is found for a secondary trajectory with quantum numbers different from the pomeron in the analyzed data.