A Tale of Two Hard Pomerons

TL;DR

This paper compares two theoretical models for hard double pomeron exchange dijet production, analyzing their predictions against experimental data from CDF and DØ to understand their differences and limitations.

Contribution

It provides a detailed comparison of factorized and nonfactorized models for double pomeron exchange, highlighting their distinct predictions and experimental implications.

Findings

CDF data suggests dominance of the factorized mechanism

DØ data shows no clear preference between mechanisms

Theoretical models struggle to reconcile CDF and DØ cross section ratios

Abstract

Two mechanisms are examined for hard double pomeron exchange dijet production, the factorized model of Ingelman-Schlein and the nonfactorized model of lossless jet production which exhibits the Collins-Frankfurt-Strikman mechanism. Comparison between these two mechanisms are made of the total cross section, $E_T$-spectra, and mean rapidity spectra. For both mechanisms, several specific models are examined with the cuts of CDF, D\O and representative cuts of LHC. Distinct qualitative differences are predicted by the two mechanisms for the CDF $y_+$-spectra and for the $E_T$-spectra for all three experimental cuts. The preliminary CDF and D\O experimental data for this process are interpreted in terms of these two mechanisms. The $y_+$-spectra of the CDF data is suggestive of domination by the factorized Ingelman-Schlein mechanism, whereas the D\O data shows no greater preference for either mechanism. An inconsistency is found amongst all the theoretical models in attempting to explain the ratio of the cross sections given by the data from these two experiments.