Exploring the effects of color reconnection on net-charge fluctuations in pp collisions at $$\sqrt{s}=2.76 \text { TeV}$$ using PYTHIA Monash

Abstract

Abstract This work explores the effects of various color reconnection (CR) configurations on the net charge fluctuations of charged particles generated in pp collisions at a center-of-mass energy of $$\sqrt{s}$$ s = 2.76 TeV, simulated with the PYTHIA Monash using the variable $$\nu _{(+,-,\text {dyn})}$$ ν ( + , - , dyn ) . The results are compared with experimental data from ALICE, revealing that the current PYTHIA simulation settings overestimate the net charge fluctuations relative to the experimental observations. Furthermore, $$\nu _{(+,-,\text {dyn})}$$ ν ( + , - , dyn ) exhibits a clear dependence on the MPICR range parameter, where increasing the range leads to more negative $$\nu _{(+,-,\text {dyn})}$$ ν ( + , - , dyn ) values, suggesting the geometric extent of CR directly modulates the strength of local charge correlation. To ensure these effects are not a trivial consequence of particle density, a comparison with a retuned NoCR baseline at fixed multiplicity was performed. This analysis confirms that CR induces a genuine dynamical shift in fluctuations that persists independently of the average charged-particle density. The study also shows that the net charge and net pion channels display the strongest suppression in $$\langle N_{\text {ch}} \rangle \nu _{(+-,\text {dyn})}$$ ⟨ N ch ⟩ ν ( + - , dyn ) compared to the net kaon and net proton channels. Overall, the study offers a useful benchmark against experimental results and sheds light on the underlying dynamics of the PYTHIA Monash.