Unveiling the effects of multiple soft partonic interactions in pp collisions at p s=13.6 TeV using a new event classifier ffi

Event classifiers based either on the charged-particle multiplicity or the event shape have been extensively used in proton-proton (pp) collisions by the ALICE Collaboration at the LHC. The use of these tools became very instrumental since the observation of fluidlike behavior in high-multiplicity pp collisions. In particular, the study as a function of the charged-particle multiplicity registered in the forward V0 ALICE detector allowed for the discovery of strangeness enhancement in high-multiplicity pp collisions. However, one drawback of the multiplicity-based event classifiers is that requiring a high charged-particle multiplicity biases the sample towards hard processes like multijet final states. These biases make it difficult to perform jet-quenching searches in high-multiplicity pp collisions. In this context, the present paper explores the use of the new event classifier, flattenicity; which uses the multiplicity calculated in the forward pseudorapidity region. To illustrate how this tool works, pp ffifficollisionsatps 1/4 13.6 TeV simulated with PYTHIA 8 are explored. The sensitivity of flattencity to multipartonic interactions as well as to the "hardness" of the collision are discussed. PYTHIA 8 predictions for the transverse momentum spectra of light-and heavy-flavored hadrons as a function of flattenicity are presented.