Measurements of groomed heavy-flavour jet substructure with ALICE

About

Recently, a variety of jet shape and substructure measurements in pp and Pb-Pb collisions have provided new insights into the processes of jet fragmentation and the mechanisms of jet interaction with the quark-gluon plasma. Grooming techniques, such as Soft Drop, allow us to access the hard splittings inside a jet by removing soft radiation emitted at large angles. These techniques provide a cleaner handle with which to explore the mechanisms of parton fragmentation both in the vacuum and in the presence of a hot QCD medium.

Thanks to the excellent tracking and particle identification of its detector, the ALICE collaboration is now capable of extending the study of jet substructure to the heavy-flavour sector by studying charm-tagged jets. Such measurements allow for the exploration of the mechanisms of parton fragmentation using a quark-enriched jet sample down to very low jet momenta and can therefore be used to identify differences between quark and gluon fragmentation as well as provide a reference for studying the flavour dependence of quark energy loss in Pb-Pb collisions.

In this talk, we show the first measurements of the groomed jet substructure variables, $z_g$ and $R_g$, using the Soft Drop algorithm for charged jets tagged by fully reconstructed D$^0$ mesons. Having access to the jet splittings involving fully reconstructed D$^0$ mesons also allows for the first direct measurement of the dead cone effect at colliders, by comparing the Lund plane of charm-tagged jets to that of inclusive jets. These results will be presented for pp collisions at $\sqrt{s}$ = 13 TeV and the prospects for similar measurements in Pb-Pb collisions will also be discussed..

0:00:00 Slide 1

0:01:56 Slide 2

0:03:52 Slide 3

0:05:48 Slide 4

0:07:43 Slide 5

0:09:39 Slide 6

0:11:35 Slide 7

0:13:30 Slide 8

0:15:26 Slide 9