Measurement of $Lambda_c^+/D^0$ as a function of event multiplicity in pp and p–Pb collisions at $sqrt{s_{NN}}=5.02$ TeV with the ALICE experiment

Measurements of charm baryon and meson production in pp and p–Pb minimum bias collisions and as a function of multiplicity, help to investigate hadronization processes and their modification across the collision systems from pp to Pb–Pb, and from low to high multiplicities. Recent measurements of the fragmentation fractions of charm hadrons in pp and p–Pb challenge the universality of fragmentation in the presence of a hadronic medium. In addition, the ratio of $p_{T}$ spectra of $Lambda_c^+/D^0$ in pp collisions, shows a separation between the highest and the lowest multiplicity classes within $5.3sigma$, with the maximum discrepancy occurring for $2 GeV/c$. Models that adopt a dynamical approach to hadronization, such as PYTHIA and the statistical hadronization model, can act as a bridge to study the connection between data and the theoretical framework.

Through the application of supervised machine learning, measurements can be enhanced in the $1 GeV/c < p_{T} < 2 GeV/c$ region, where the signal is fully obscured by the detector's resolution and the large combinatorial background. This issue can be addressed by training a binary classifier based on the topological characteristics of candidates. A $6sigma$ significance signal can be retrieved in a region initially devoid of any signal. These regions are critical, as low $p_{T}$ candidates are significantly affected by coalescence mechanisms.