Unveiling the effects of multiple soft partonic interactions in <math display="inline"><mi>p</mi><mi>p</mi></math> collisions at <math display="inline"><mrow><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo><mn>13.6</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></mrow></math> using a new event classifier

Event classifiers based either on the charged-particle multiplicity or the event shape have been extensively used in proton-proton (<math display="inline"><mi>p</mi><mi>p</mi></math>) 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 <math display="inline"><mi>p</mi><mi>p</mi></math> 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 <math display="inline"><mi>p</mi><mi>p</mi></math> 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 <math display="inline"><mi>p</mi><mi>p</mi></math> 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 collisions at <math display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13.6</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> 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.