The interaction region of high energy protons

Abstract

New experimental data about proton-proton collisions obtained atthe LHC allow to widen strongly the energy interval where one gets some knowledge about the structure of their interaction region. Using the unitarity relation in combination with experimental data about the elastic scattering in the diffraction cone, it is shown how the shape and the darkness of the interaction region of colliding protons change with increase of their energies. In particular, the collisions become fully absorptive at small impact parameters at LHC energies that results in some special features of inelastic processes as well. Possible evolution of the shape from the dark core at the LHC to the fully transparent one is discussed that implies the terminology of the black disk would be replaced by the black torus. The parameter which determines the opacity of central collisions also plays a crucial role in the behavior of the differential cross section of elastic scattering outside the diffraction cone where the predictions of all phenomenological models failed at LHC energies. The role of the ratio of real to imaginary part of the elastic scattering amplitude at non-forward scattering becomes decisive there as seen from the unitarity condition. The obtained results allow to estimate this ratio outside the diffraction cone for the first time by comparison with experiment at LHC energies which happens to be drastically different from its values measured at forward scattering. Moreover, the behaviors of the real and imaginary parts separately differ in different phenomeno- logical models and in the approach based on the unitarity condition. This problem is still waiting for its resolution. All the conclusions are only obtained in the framework of the indubitable unitarity condition using experimental data about the elastic scattering.

25 pages, 6 figures, 1 Table, extended version, mini-review for Physics-Uspekhi

References in corpus (7)

• Transverse nucleon structure and diagnostics of hard parton-parton processes at LHC
• Impact analysis of TOTEM data at the LHC: black disk limit exceeded
• Hadron collisions at ultrahigh energies: black disk or resonant disk modes?
• Polynomial fits and the proton radius puzzle
• Exploring central opacity and asymptotic scenarios in elastic hadron scattering
• Jets in multiparticle production in and beyond geometry of proton-proton collisions at the LHC
• pp Elastic Scattering at LHC Energies

Cited by in corpus (33)

• Scattering of wave packets with phases
• Hollowness in $pp$ and $p\bar{p}$ scattering in a Regge model
• Evidence of Odderon-exchange from scaling properties of elastic scattering at TeV energies
• Proton-proton hollowness at the LHC from inverse scattering
• Exploring central opacity and asymptotic scenarios in elastic hadron scattering
• The new scattering mode emerging at the LHC?
• Unexpected properties of interactions of high energy protons
• Probing phase of a scattering amplitude beyond the plane-wave approximation
• Observation of Odderon Effects at LHC energies -- A Real Extended Bialas-Bzdak Model Study
• Critical behavior of cross sections at LHC
• Recent Results from the CERN LHC Experiment TOTEM -- Implications for Odderon Exchange
• Directed flow in asymmetric nucleus-nucleus collisions and the inverse Landau-Pomeranchuk-Migdal effect
• Central and peripheral interactions of hadrons
• Is There a Hollow Inside the Proton?
• Reflecting disk with black edge
• The multilayer structure of protons
• Central elastic scattering
• On the shape of nucleons at high energies
• The Tsallis entropy and the BKT-like phase transition in the impact parameter space for $pp$ and $\bar{p}p$ collisions
• Analytization of elastic scattering amplitude
• An approach to the leading Regge pole
• Resonant mode of elastic scattering of protons at ultra-high energies
• Lévy $\alpha$-stable model for the non-exponential low-$|t|$ proton-proton differential cross section
• Hollowness effect and entropy in high energy elastic scattering
• Proton Internal Pressure in $pp$ and $\bar{p}p$ Elastic Scattering
• Proton Holography -- Discovering Odderon from Scaling Properties of Elastic Scattering
• Correlations among elastic and inelastic cross-sections and slope parameter
• Evolution equation for elastic scattering of hadrons
• The Effects of the Tsallis Entropy in the Proton Internal Pressure
• Restrictions on pp scattering amplitude imposed by first diffraction minimum data obtained by TOTEM at LHC
• An investigation on the leading and subleading high-energy behavior of hadron-hadron total cross sections using a best-fit analysis of hadronic scattering data
• Asymptotic regimes for hadron diffractive scatterings and coulomb interaction. Arguments for the black disk mode
• Chiral Symmetry Restoration using the Running Coupling Constant from the Light-Front Approach to QCD