Fine structure of the diffraction cone: from ISR to the LHC

Abstract

Following earlier findings, we argue that the low-$|t|$ structure in the elastic diffractive cone, recently reported by the TOTEM Collaboration at $8$ TeV, is a consequence of the threshold singularity required by $t-$channel unitarity, such as revealed earlier at the ISR. By using simple Regge-pole models, we analyze the available data on the $pp$ elastic differential cross section in a wide range of c.m. energies, namely those from ISR to LHC8, obtaining good fits of all datasets. This study hints at the fact that the non-exponential behaviour observed at LHC8 is a recurrence of the low-$|t|$ "break" phenomenon, observed in the seventies at ISR, being induced by the presence of a two-pion loop singularity in the Pomeron trajectory.

11 pages, 6 figures, 7 tables. Invited contribution to the Gribov-85 Memorial Volume "Exploring Quantum Field Theory", to be published by World Scientific

References in corpus (1)

• Evidence for non-exponential elastic proton-proton differential cross-section at low |t| and sqrt(s) = 8 TeV by TOTEM

Cited by in corpus (4)

• Measurement of Elastic pp Scattering at $\sqrt{s}$ = 8 TeV in the Coulomb-Nuclear Interference Region - Determination of the $\rho$-Parameter and the Total Cross-Section
• Introduction to the physics of the total cross-section at LHC: A Review of Data and Models
• Simple Lévy-$\alpha$ stable model analysis of elastic $pp$ and $p\bar{p}$ low-$|t|$ data from SPS to LHC energies
• Evidence for Non-Exponential Differential Cross-Section of pp Elastic Scattering at Low |t| and $\sqrt{s}$ = 8 TeV by TOTEM