Soft pomerons and the forward LHC data

Abstract

Recent data from LHC13 by the TOTEM Collaboration on σtotand ρhave 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 σtotdatum and the unexpected decrease in the ρvalue are well described by the maximal Odderon dominance at the highest energies. Here, we discuss the applicability of Pomeron dominance through fits to the most complete setof forward data from ppand ¯ppscattering. We consider an analytic parameterization for σtot(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 ρparameter is analytically determined by means of dispersion relations. We carry out fits to ppand ¯ppdata on σtotand ρin 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 three independent ensemblesby 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 completeset of experimental data presently available.