Why Do We Need Detailed Analysis of Data to Understand the Mechanisms of \(pp\) Collisions at the LHC?

In this paper, we investigate the transverse momentum spectra of charged particles in proton–proton collisions at the LHC using detailed event-by-event simulations with the <span class="sf">PYTHIA 8</span> event generator. Rather than relying solely on average observables such as the mean transverse momentum, we analyse the full shape of the spectra across different charged-particle multiplicity intervals. Our results show that significant variations in spectral shape occur with increasing multiplicity, revealing a transition from soft to hard processes that is not captured by global mean values. Comparisons with other commonly used Monte Carlo models, including <span class="sf">Herwig 7</span> and <span class="sf">EPOS 4</span>, demonstrate that while the mean values are broadly consistent across generators, the underlying spectral shapes differ. Abstract Published by the Jagiellonian University 2025 authors