pp Elastic Scattering at LHC and Nucleon Structure

Abstract

High energy elastic pp scattering at the Large Hadron Collider (LHC) at c.m. energy 14 TeV is predicted using the asymptotic behavior of σ tot (s) and ρ(s) known from dispersion relation calculations and the measured elasticpp differential cross section at √ s = 546GeV. The effective field theory model underlying the phenomenological analysis describes the nucleon as having an outer cloud of quark-antiquark condensed ground state, an inner core of topological baryonic charge of radius ≃ 0.44F and a still smaller valence quark-bag of radius 0.1 F. The LHC experiment TOTEM (Total and Elastic Measurement), if carried out with sufficient precision from |t| = 0 to |t| > 10 GeV 2 , will be able to test this structure of the nucleon. . Soft diffractive processes mediated by Pomerons including high-mass diffractive dissciation have also been proposed to describe elastic scattering at LHC for small |t| 0.5 GeV 2 [11]. Study of the field theory model further indicates that the nucleon has an outer cloud of quark-antiquark condensed ground state analogous to a superconducting state, an inner core of topological baryonic charge and a still smaller quark-bag of valence quarks. The elastic scattering experiment TOTEM at LHC [12], if carried out with sufficient precision, will be able to identify these three regions inside the nucleon by their characteristic behaviors reflected in the elastic differential cross section. The present investigation reports our quantitative prediction of dσ/dt at LHC at √ s = 14 TeV.

Introduction to the physics of the total cross section at LHC

“…96. In the left panel, we show a compilation of different model predictions at √ s = 14 TeV from [340], done in 2007, and at right we see how predictions at √ s = 7 TeV compared with actual LHC data, as shown from K. Eggert's talk at Hadron Collider Physics Symposium, November 2011, Paris, France. As new results from LHC appeared at √ s = 7 TeV the parameters of some models had to be updated, and agreement with the new data was easily obtained.…”

“…In [339,340], as in the previous papers, the proton is described through three basic elements: an external cloud of qq pairs (sea quarks), an inner shell of baryonic charge and a central quark-bag containing the valence quarks. The external cloud and the inner shell have an obvious connection to QCD phenomenology, a pion cloud or some gluon condensate and the valence quarks, while one nucleon probes the baryonic charge of the other via ω-exchange.…”

Entropy Production and Particle Yields in Heavy Ion Collisions at LHC

“…With these simplifications and with Islam's differential cross sections [22] we have numerically solved Eqs. (18) and we have calculated the S/N production for the accelerator energies used so far, as well as for LHC.…”

“…In Section 4 we evaluated the expected LHC specific entropy and we got 65.7. However, the experimental differential cross sections are not yet measured above Tevatron momenta; we have used extrapolations [22] assuming that nothing new happens there. This is probably so; but if we cross the energy range of "something new" between Tevatron and LHC energies, then in first approximation a "reasonance peak" is expected, so increasing the cross section and so the S/N.…”