Several Effects Unexplained by QCD

Igor Dremin

doi:10.3390/universe4050065

Abstract

Several new experimental discoveries in high energy proton interactions, yet unexplained by QCD, are discussed in the paper. The increase of the cross sections with increasing energy from ISR to LHC, the correlation between it and the behavior of the slope of the elastic diffraction cone, the unexpected increase of the survival probability of protons in the same energy range, the new structure of the elastic differential cross section at rather large transferred momenta (small distances) and the peculiar ridge effect in high multiplicity inelastic processes are still waiting for QCD interpretation and deeper insight in vacuum.

Highlights

Cosmic-ray studies revealed many new unexpected features of particle interactions
The proton-proton total cross section was steadily decreasing with energy increase
It is interesting that at the same energies the slope of the elastic diffraction cone drastically changes its energy dependence and the real part of the forward scattering amplitude passes through zero changing its sign as discussed in the Section 3 below. Such a behavior means that the transverse size of the interaction region of protons becomes larger standing of the Quantum ChromoDynamics (QCD)-vacuum properties

Summary

Introduction

Cosmic-ray studies revealed many new unexpected features of particle interactions. The invention of particle accelerators and, later on, colliders helped to learn paticle properties in more detail. Two events must be specially emphasized—the 1983 discovery [1] at the Super Proton Synchrotron (SPS) of the intermediate vector bosons W± and Z0 with masses of about 80 and 91 GeV, mediators of the weak interaction, and the 2012 discovery [2,3] at the LHC of the final scalar piece of the Standard Model—the Higgs boson with mass of about 125 GeV It validates the Standard Model and shows a right way to understanding the cornerstone problem of the origin of masses of some fundamental particles and constituents of matter. The most widely used theoretical method in physics is the perturbative approach with its power series expansion using the smallness of the coupling constant It can be applied in QCD only for collisions with large transferred momenta (or high masses) where the coupling strength becomes small due to the asymptotic freedom property. Some relevant experimental results about proton interactions and their implications are discussed below

The Energy Behavior of the Cross Sections

The Energy of the obtained

The Elastic

The Jets and the Ridge in Inelastic Processes