Observation of Odderon effects at LHC energies: a real extended Bialas–Bzdak model study

The unitarily extended Bialas–Bzdak model of elastic proton–proton scattering is applied, without modifications, to describe the differential cross-section of elastic proton–antiproton collisions in the TeV energy range, and to extrapolate these differential cross-sections to LHC energies. In this model-dependent study we find that the differential cross-sections of elastic proton–proton collision data at 2.76 and 7 TeV energies differ significantly from the differential cross-section of elastic proton–antiproton collisions extrapolated to these energies. The elastic proton–proton differential cross-sections, extrapolated to 1.96 TeV energy with the help of this extended Bialas–Bzdak model do not differ significantly from that of elastic proton–antiproton collisions, within the theoretical errors of the extrapolation. Taken together these results provide a model-dependent, but statistically significant evidence for a crossing-odd component of the elastic scattering amplitude at the at least 7.08 sigma level. From the reconstructed Odderon and Pomeron amplitudes, we determine the $$\sqrt{s}$$ s dependence of the corresponding total and differential cross-sections.

Evidence of Odderon-exchange from scaling properties of elastic scattering at TeV energies

We study the scaling properties of the differential cross section of elastic proton–proton (pp) and proton–antiproton ($$p\bar{p}$$ p p ¯ ) collisions at high energies. We introduce a new scaling function, that scales – within the experimental errors – all the ISR data on elastic pp scattering from $$\sqrt{s} = 23.5$$ s = 23.5 –62.5 GeV to the same universal curve. We explore the scaling properties of the differential cross-sections of the elastic pp and $$p\bar{p}$$ p p ¯ collisions in a limited TeV energy range. Rescaling the TOTEM pp data from $$\sqrt{s} = 7$$ s = 7 TeV to 2.76 and 1.96 TeV, and comparing it to D0 $$p\bar{p}$$ p p ¯ data at 1.96 TeV, our results provide an evidence for a t-channel Odderon exchange at TeV energies, with a significance of at least 6.26$$\sigma $$ σ . We complete this work with a model-dependent evaluation of the domain of validity of the new scaling and its violations. We find that the H(x) scaling is valid, model dependently, within $$200~\hbox {GeV}\le \sqrt{s} \le 8$$ 200 GeV ≤ s ≤ 8 TeV, with a $$-t$$ - t range gradually narrowing with decreasing colliding energies.

A new approach to modelling elastic and inelastic photon-initiated production at the LHC: SuperChic 4

We present the results of the new Monte Carlo implementation of photon-initiated production in proton–proton collisions, considering as a first example the case of lepton pair production. This is based on the structure function calculation of the underlying process, and focusses on a complete account of the various contributing channels, including the case where a rapidity gap veto is imposed. We provide a careful treatment of the contributions where either (single dissociation), both (double dissociation) or neither (elastic) proton interacts inelastically and dissociates, and interface our results to for showering and hadronization. The particle decay distribution from dissociation system, as well the survival probability for no additional proton–proton interactions, are both fully accounted for; these are essential for comparing to data where a rapidity gap veto is applied. We present detailed results for the impact of the veto requirement on the differential cross section, compare to and find good agreement with ATLAS 7 TeV data on semi-exclusive production, and provide a new precise evaluation of the background from semi-exclusive lepton pair production to SUSY particle production in compressed mass scenarios, which is found to be low.

Eikonal model analysis of elastic proton–proton collisions at 52.8 GeV and 8 TeV

Under the influence of standardly used description of Coulomb-hadronic interference proposed by West and Yennie the protons have been interpreted as transparent objects; elastic events have been interpreted as more central than inelastic ones. It will be shown that using eikonal model the protons may be interpreted in agreement with usual ontological conception; elastic processes being more peripheral than inelastic ones. The corresponding results (differing fundamentally from the suggested hitherto models) will be presented by analyzing the most ample elastic data set measured at the ISR energy of 52.8 GeV and the LHC energy of 8 TeV. Detailed analysis of measured differential cross section will be performed and possibility of peripheral behavior on the basis of eikonal model will be presented. The impact of recently established electromagnetic form factors on determination of quantities specifying hadron interaction determined from the fits of experimental elastic data in the broadest region of momentum transfers will be analyzed.

Born Approximation for Polarization Observables at the Scattering of Protons by 40Ca Nuclei

A development of the optical model for the description of the hadron-nucleus scattering is proposed. When describing the behavior of polarization observables for the elastic proton scattering on 40Ca nuclei in the energy interval from 200 to 800 MeV, the Born approximation is used. Analytical expressions for the scattering amplitudes, as well as for the differential cross-sections and polarization observables, are obtained. The comparison of the scattering observables calculated in the 1st and 2nd Born approximations is made. It is shown that the observables calculated in this approach are in a reasonable agreement with the available experimental data.