Jet substructure in pp collisions with ALICE

TL;DR

This paper presents high-precision measurements of jet substructure in proton-proton collisions at the LHC using ALICE, providing insights into QCD phenomena and jet evolution through novel observables and comparisons with theoretical models.

Contribution

It introduces new jet substructure measurements in pp collisions with ALICE, including generalized angularities and the dead-cone effect, enhancing understanding of jet physics at low transverse momentum.

Findings

Observation of the dead-cone effect in QCD

Comparison of measurements with event generator predictions

High-precision access to soft jet components

Abstract

Jet substructure observables have been used by experiments at the Large Hadron Collider (LHC) as instruments to search for new physics as well as to study perturbative and nonperturbative processes in quantum chromodynamics (QCD). Some observables are infrared and collinear safe and thus easily comparable to first-principles calculations, while others offer direct insight into specific physical phenomena such as the quark-gluon plasma formed in heavy-ion collisions. The high-precision capability of the ALICE tracking system allows a unique opportunity at LHC energies to measure tracks with low transverse momentum, permitting high precision access to the softer components inside jets with an excellent angular resolution. We present some recent charged-particle jet substructure measurements in pp collisions with ALICE, including the generalized jet angularities, the angular jet axes differences, and the direct observation of the dead-cone effect in QCD using the primary Lund Plane. These results provide new insights into the evolution of jets by comparing ALICE measurements to predictions from different event generators and perturbative QCD calculations.