Soft Pomerons and the Forward LHC Data

TL;DR

This paper evaluates whether soft Pomeron dominance can explain the latest forward scattering data from LHC, considering various datasets and uncertainties, and finds it remains a viable model within current experimental errors.

Contribution

It introduces a comprehensive analysis of forward $pp$ and $ar{p}p$ scattering data using an analytic Pomeron model with multiple datasets and uncertainty evaluations.

Findings

Soft Pomeron model is consistent with current data within uncertainties.

Inclusion of different datasets affects the fit results.

The model does not contradict the experimental data at high energies.

Abstract

Recent data from LHC13 by the TOTEM Collaboration on $\sigma_{tot}$ and $\rho$ have indicated disagreement with all the Pomeron model predictions by the COMPETE Collaboration (2002). On the other hand, as recently demonstrated by Martynov and Nicolescu (MN), the new $\sigma_{tot}$ datum and the unexpected decrease in the $\rho$ value are well described by the maximal Odderon dominance at the highest energies. Here, we discuss the applicability of Pomeron dominance through fits to the \textit{most complete set} of forward data from $pp$ and $\bar{p}p$ scattering. We consider an analytic parametrization for $\sigma_{tot}(s)$ consisting of non-degenerated Regge trajectories for even and odd amplitudes (as in the MN analysis) and two Pomeron components associated with double and triple poles in the complex angular momentum plane. The $\rho$ parameter is analytically determined by means of dispersion relations. We carry out fits to $pp$ and $\bar{p}p$ data on $\sigma_{tot}$ and $\rho$ in the interval 5 GeV - 13 TeV (as in the MN analysis). Two novel aspects of our analysis are: (1) the dataset comprises all the accelerator data below 7 TeV and we consider \textit{three independent ensembles} by adding: either only the TOTEM data (as in the MN analysis), or only the ATLAS data, or both sets; (2) in the data reductions to each ensemble, uncertainty regions are evaluated through error propagation from the fit parameters, with 90 \% CL. We argument that, within the uncertainties, this analytic model corresponding to soft Pomeron dominance, does not seem to be excluded by the \textit{complete} set of experimental data presently available.