Double Parton Interactions inppandpACollisions

Daniele Treleani,Simona Salvini,Giorgio Calucci,G.E Bruno,G Chiodini,S Spagnolo,P Colangelo,F De Fazio,E Nappi,D.M Creanza,C Corianò

doi:10.1051/epjconf/201612900013

Abstract

As a consequence of the increasingly large flux of partons at small x , Double Parton Interactions (DPI) play an increasingly important role at high energies. A detail understanding of DPI dynamics is therefore mandatory, for a reliable subtraction of the background in the search of new physics. On the other hand, DPI are an interesting topic of research by themselves, as DPI probe the hadron structure in a rather different way, as compared with the large pt processes usually considered. In this note we will make a short illustration of some of the main features characterizing DPI in pp and in pA collisions.

Highlights

The rapid increase of the parton flux at small x causes a dramatic rise of all cross sections with large momentum transfer exchange in high energy hadronic collisions [1,2]
Multiple Parton Interactions (MPIs) introduce the possibility of different hard partonic interactions in a e-mail: daniele.treleani@ts.infn.it e-mail: Giorgio.Calucci@ts.infn.it e-mail: salmonae@gmail.com given inelastic event and, while each inelastic event contributes with multiplicity ’one’ to the inelastic cross section, each inelastic event contributes with the multiplicity of hard partonic interactions to the inclusive hard cross section
In this way, when the average multiplicity of hard partonic interactions in a inelastic event is large, the inclusive cross section is no more bounded by the value of the total inelastic cross section [3]

Summary

Introduction

The rapid increase of the parton flux at small x causes a dramatic rise of all cross sections with large momentum transfer exchange in high energy hadronic collisions [1,2]. By looking at fig.3, within large experimental errors, the observed values of the effective cross section are approximately constant (∼ 15 mb) and do not seem to depend on the C.M. energy (Fermilab, LHC) the reaction channel (4 j; γ3 j; γγ2 j; γb(c)2 j; W j j; J/Ψ J/Ψ; Z J/Ψ; Υ D0; J/Ψ D0) the values of x and Q2 There is on the contrary a clear indication that the effective cross section is sizably smaller (≈ 2-4 mb) in the case (J/Ψ J/Ψ) and (J/Ψ Υ) production Notice that σe f f is sizably smaller as compared with σinel, which is an indication of strong partonic correlations in the hadron structure.

Results

Conclusion