Disentangling the soft and hard components of the pp collisions using the sphero(i)city approach

Abstract

A new method to extract information from the pp data is proposed. The approach is based on the use of the event structure variables: sphericity and spherocity, to split the data into enhanced soft and hard processes samples corresponding to events with large and low numbers of multi-parton interactions, respectively. The present study was developed in the framework of Pythia 8.180 for inelastic pp collisions at sqrt(s) =7 TeV. As an application of the method, a study of the identified particle transverse momentum spectra and their ratios; is presented for soft (isotropic) and hard (jetty-like) events. The flow-like effect on these observables due to multi-parton interactions and color reconnection is relevant for soft events suggesting that partons inside the jet do not feel color reconnection and its flow-like consequences.