Odderon

In elastic collisions, the total kinetic energy of the system is conserved. Thus the identity of the scattered particles is not modified, no excited states and/or new particles are produced. The kinematics of these collisions is governed by the conservation of both energy and momentum. Data on high-energy elastic proton–proton collisions provided by the TOTEM Collaboration in a teraelectronvolt energy range, together with data from the DØ experiment on elastic proton–antiproton collisions at the Tevatron collider were key ingredients in the discovery of the odderon-exchange. The observed characteristics of the proton–proton collisions did not match the characteristics of the proton–antiproton collisions. As a result, there is an interaction-mediating family of particles (Regge trajectory) that can result in such a deviation in the range of strong interactions. == Discovery ==

The first paper on the theoretical prediction of possible odderon exchange was published in 1973 by Basarab Nicolescu and Leszek Łukaszuk. In December 2020, the DØ and TOTEM Collaborations made public their CERN and Fermilab approved preprint In this model dependently determined domain of validity, the Hungarian-Swedish team utilized a direct data-to-data comparison and showed that energy independent scaling function of elastic proton–proton collisions is significantly different from the scaling function of elastic proton–antiproton collisions, hence providing a statistically significant signal for the exchange of the elusive odderon. The preprint of this analysis was made public in December 2019 and its final form it was published in February 2021. This paper utilized a previously published theoretical model, the so-called real-extended Bialas-Bzdak model, to extrapolate not only the elastic proton–proton scattering data from the LHC energies to the DØ energy of 1.96 TeV but also to extrapolate the elastic proton–antiproton scattering data from 0.546 and 1.96 TeV to the LHC energies of 2.76 TeV and 7 TeV. Evaluating the proton–proton data with a model increased the uncertainty and decreased the odderon signal from proton–proton scattering data alone, but this decrease was well over-compensated with the ability of the model to evaluate theoretically the proton–antiproton scattering at the LHC energies, leading to an overall increase of the statistical significance from 6.26 to 7.08 σ signal. == Chronology of articles discovering odderon exchange ==