Measurement of angular and momentum distributions of charged-particles within and around jets in Pb+Pb and $pp$ collisions at $\sqrt{s_{NN}}= 5.02$ TeV with ATLAS at the LHC

Studies of the fragmentation of jets into charged particles in heavy-ion collisions can help in understanding the mechanism of jet quenching by the hot and dense QCD matter created in such collisions, the quark-gluon plasma. This note presents a measurement of the angular distribution of charged particles around the jet axis in $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV Pb+Pb and $pp$ collisions, done using the ATLAS detector at the LHC. The measurement is performed inside jets reconstructed with the anti-$k_{t}$ algorithm with radius parameter $R = $ 0.4, and is extended to regions outside the jet cone. Results are presented as a function of Pb+Pb collision centrality, and both jet and charged-particle transverse momenta.