SCALE FACTORS FROM MULTIPLE HEAVY QUARK PRODUCTION AT THE LHC

Abstract

As a consequence of the high partonic luminosity at the LHC we expect a large number of events with two or more heavy quark pairs produced contemporarily in the same proton-proton collision. The high efficiency in detecting heavy quarks and the capability of the ALICE detector to measure at very low transverse momenta, where the effects of multiparton interactions are more pronounced, suggests to study multiple heavy quark production as an example of multiparton processes with the ALICE detector and measure the scale factors which are related to spatial density of partons in the proton l. The simplest case of multiparton scattering process is the double parton collision where two disconnected parton scatterings take place in the same hadron-hadron event. In the hypothesis of no correlations between the momentum fractions and factorization of the transverse degrees of freedom in the two-body parton distribution, the cross section to produce four heavy quarks, in a double parton scattering, is proportional to the product of two single parton scattering cross section. Hence in order to get the double parton scattering cross section we need to compute the heavy quarks QQ cross section which is usually calculated in the QCD collinear approximation at the nextto-leading-order z. The cross section is affected by several large theoretical uncertainties and recent experimental data on the beauty production, at the Tevatron, have shown that next-to-leading-order perturbation theory fails, in