Comunicazione
Minimum-bias and the underlying event measurements with ALICE at the LHC.
Tripathy S. per la ALICE Collaboration
To understand the similarities between small and large collision systems, one can study minimum-bias and underlying-event (UE) observables in pp, p-Pb and Pb-Pb collisions. In this contribution, we present the results obtained using UE techniques, allowing the measurement of the particle density in different topological regions with respect to the leading trigger particle. The charged-particle multiplicity in the transverse region is used as a multiplicity estimator to study particle production mechanisms. The UE studies are used to search for jet-like modification. In addition, results on very forward energy, measured by the ALICE zero-degree calorimeters, and differential studies of particle production will be presented for pp and p-Pb collisions. In the second part of the contribution, we will introduce the upgraded Run 3 ALICE configuration and the new Monolithic Active Pixel Sensors-based Inner Tracking System, which allows full tracking and vertexing for $|\eta| < 2.5$. The performance of the new detector and the tracking/matching algorithms will be presented for the $\sqrt{s} = 900$ GeV pp pilot-beam data taken in autumn 2021.