This paper presents a fully corrected measurement of the energy-energy correlator (EEC) within jets in pp collisions. The EEC traces the energy flow as a highly energetic parton undergoes a QCD shower followed by the confinement of partons into hadrons, probing the correlation function of the energy flow inside jets. The EEC observable is measured as a function of the charged particle pair angular distance, RL, for (Formula presented.). In the perturbative region (large RL), a good agreement between the data and a next-to-leading-log perturbative QCD calculation is observed. In the nonperturbative region (small RL), the data exhibit a linear RL dependence. There is a transition region in between, characterized by a turnover in the EEC distribution, indicating where hadronization effects begin to dominate. The peak of this transition region is located at (Formula presented) for jets of various energies, indicating a common energy scale for the hadronization process. State-of-the-art Monte Carlo event generators are compared with the measurements, and can be used to constrain the parton shower and hadronization mechanisms.
Exposing the parton-hadron transition within jets with energy-energy correlators in pp collisions at √𝑠 =5.02 TeV
Caliva, A.;De Caro, A.;De Gruttola, D.;De Pasquale, S.;Funicello, N.;Pucillo, S.;Ripoli, C.;Virgili, T.;
2026
Abstract
This paper presents a fully corrected measurement of the energy-energy correlator (EEC) within jets in pp collisions. The EEC traces the energy flow as a highly energetic parton undergoes a QCD shower followed by the confinement of partons into hadrons, probing the correlation function of the energy flow inside jets. The EEC observable is measured as a function of the charged particle pair angular distance, RL, for (Formula presented.). In the perturbative region (large RL), a good agreement between the data and a next-to-leading-log perturbative QCD calculation is observed. In the nonperturbative region (small RL), the data exhibit a linear RL dependence. There is a transition region in between, characterized by a turnover in the EEC distribution, indicating where hadronization effects begin to dominate. The peak of this transition region is located at (Formula presented) for jets of various energies, indicating a common energy scale for the hadronization process. State-of-the-art Monte Carlo event generators are compared with the measurements, and can be used to constrain the parton shower and hadronization mechanisms.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
