Untitled

Abstract

Double parton scattering, occurring in high energy hadron-hadron collisions, e.g. at the LHC, is usually investigated through model dependent analyses of the so called effective cross section σ ef f . We present a dynamic approach to this fundamental quantity making use of a Light-Front model treatment. Within such a framework σ ef f is initially evaluated at low energy scale using the model and then, through QCD evolution, at high energy scale to reach the experimental conditions. Our numerical outcomes are consistent with the present experimental analyses of data in kinematical region we investigate. An important result of the present work is the x i dependence of σ ef f , a feature directly connected to double parton correlations and which could unveil new information on the three dimensional structure of the proton.

Relativistic effects in model calculations of double parton distribution functions

“…[22], dPDFs have been calculated starting from their Light-Cone correlator, which formally defines them in QCD. A suitable expression for dPDFs has been presented in Ref.…”

“…Here, as in Ref. [22], a factorization between the spin and the spatial part of the proton wave function is assumed. Let us remark that, thanks to this rigorous approach, the correct support of dPDFs is fulfilled, i.e.…”

“…In the moderate large values of fractional momenta, x, natural domain of CQM with realistic potentials, as dis- cussed in Refs. [21,22,36], calculations show that both the factorization of dPDFs as a product of single parton distributions and, perhaps more interestingly, the (x 1 , x 2 ) − k ⊥ factorization are violated. For recent results on the breaking of the factorization on the x 1 and x 2 dependence, see Ref.…”

“…Given this situation, many features of dPDFs are essentially unconstrained. It is therefore clear that non perturbative methods may give access to some relevant properties on these distributions [20][21][22][23][24][25], allowing, for example, to establish to which extent such dPDFs models may correctly reproduce the magnitudo of the transverse correlation encoded in σ ef f , see for instance results of Refs. [26,27] on this point.…”

“…[22], where dPDFs have been calculated in valence region within a fully relativistic covariant treatment, the so called Light-Front (LF) approach, we identify model independent effects induced on dPDFs by the relativistic treatment, in particular the violation of the factorized ansatz and the effects of parton correlation in the transverse plane in the proton structure. We also try to quantify the corresponding impact on observable-related quantities.…”