This article reports measurements of the angle between differently defined jet axes in pp collisions at root s = 5.02TeV carried out by the ALICE Collaboration. Charged particles at midrapidity are clustered into jets with resolution parameters R = 0.2 and 0.4. The jet axis, before and after Soft Drop grooming, is compared to the jet axis from the Winner-Takes-All (WTA) recombination scheme. The angle between these axes, Delta R-axis, probes a wide phase space of the jet formation and evolution, ranging from the initial high-momentum-transfer scattering to the hadronization process. The Delta R-axis observable is presented for 20 < p(T)(ch jet) < 100 GeV/c, and compared to predictions from the PYTHIA 8 and Herwig 7 event generators. The distributions can also be calculated analytically with a leading hadronization correction related to the non-perturbative component of the Collins Soper-Sterman (CSS) evolution kernel. Comparisons to analytical predictions at nextto-leading-logarithmic accuracy with leading hadronization correction implemented from experimental extractions of the CSS kernel in Drell-Yan measurements are presented. The analytical predictions describe the measured data within 20% in the perturbative regime, with surprising agreement in the non-perturbative regime as well. These results are compatible with the universality of the CSS kernel in the context of jet substructure.

Measurement of the angle between jet axes in pp collisions at $$ \sqrt{s} $$ = 5.02 TeV

P. Cortese;L. Ramello;M. Sitta;
2023-01-01

Abstract

This article reports measurements of the angle between differently defined jet axes in pp collisions at root s = 5.02TeV carried out by the ALICE Collaboration. Charged particles at midrapidity are clustered into jets with resolution parameters R = 0.2 and 0.4. The jet axis, before and after Soft Drop grooming, is compared to the jet axis from the Winner-Takes-All (WTA) recombination scheme. The angle between these axes, Delta R-axis, probes a wide phase space of the jet formation and evolution, ranging from the initial high-momentum-transfer scattering to the hadronization process. The Delta R-axis observable is presented for 20 < p(T)(ch jet) < 100 GeV/c, and compared to predictions from the PYTHIA 8 and Herwig 7 event generators. The distributions can also be calculated analytically with a leading hadronization correction related to the non-perturbative component of the Collins Soper-Sterman (CSS) evolution kernel. Comparisons to analytical predictions at nextto-leading-logarithmic accuracy with leading hadronization correction implemented from experimental extractions of the CSS kernel in Drell-Yan measurements are presented. The analytical predictions describe the measured data within 20% in the perturbative regime, with surprising agreement in the non-perturbative regime as well. These results are compatible with the universality of the CSS kernel in the context of jet substructure.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11579/166988
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