2025/06/06 by Sahu, Dushmanta, Ortiz, Antonio, Campos, Victor
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph)
paper · doi:10.48550/arxiv.2506.06587
To understand the dynamics of jet-medium interaction in small systems such as proton-proton (pp) and proton-lead (p-Pb) collisions at √s\rm NN = 5.02 TeV, particle production is studied in three distinct topological regions defined with respect to the charged particle with the highest transverse momentum in the event (p\rm T\rm trig). The jet-like yield is defined by the particle density in the toward region (|Δφ|<π/3) after subtracting that in the transverse region (π/3<|Δφ|<2π/3). The activity on the transverse side is used as a proxy for medium-like effects. Three different Monte Carlo event generators -- Pythia8, a multiphase transport (AMPT) model, and EPOS4 -- are employed to investigate particle yields as a function of p\rm T\rm trig in the interval 0.5-20 GeV/c. Calculations are performed for the p\rm T threshold of 0.5 GeV/c at mid-rapidity (|η| < 0.8). The jet-like yield in the toward region for pp collisions show interesting dynamics; they are significantly affected by the medium-like effects in the low to intermediate p\rm T\rm trig (<8 GeV/c) which is studied through color reconnection and hydrodynamics in Pythia8 and EPOS4, respectively. However, the results from AMPT show that the jet-like yield is medium-like modified throughout the entire p\rm T\rm trig range. The jet-like yield in p-Pb collisions using AMPT is also studied. Notably, a dip structure that is observed in the jet-like signal ratio of pp to p-Pb at low p\rm T\rm trig in ALICE data, is reproduced by AMPT model with string melting on, pointing to possible medium-like behavior in small systems. The results of this article also underscore the importance of high-p\rm T\rm trig (p\rm T\rm trig > 8 GeV/c) for minimizing underlying event biases in jet-related studies.