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

TL;DR

The TOTEM experiment measured elastic proton-proton scattering at 8 TeV, revealing a non-exponential behavior in the differential cross-section at low |t| with high precision, challenging previous assumptions.

Contribution

This study provides the first high-precision evidence of non-exponential behavior in the elastic scattering differential cross-section at 8 TeV, using extended polynomial models.

Findings

Excludes purely exponential differential cross-section with >7 sigma significance.

Supports quadratic and cubic polynomial models for data fit.

Total cross-section estimates consistent with previous measurements.

Abstract

The TOTEM experiment has made a precise measurement of the elastic proton-proton differential cross-section at the centre-of-mass energy sqrt(s) = 8 TeV based on a high-statistics data sample obtained with the beta* = 90 optics. Both the statistical and systematic uncertainties remain below 1%, except for the t-independent contribution from the overall normalisation. This unprecedented precision allows to exclude a purely exponential differential cross-section in the range of four-momentum transfer squared 0.027 < |t| < 0.2 GeV^2 with a significance greater than 7 sigma. Two extended parametrisations, with quadratic and cubic polynomials in the exponent, are shown to be well compatible with the data. Using them for the differential cross-section extrapolation to t = 0, and further applying the optical theorem, yields total cross-section estimates of (101.5 +- 2.1) mb and (101.9 +- 2.1) mb, respectively, in agreement with previous TOTEM measurements.