Jet substructure is a powerful tool to probe the perturbative regime of jet evolution in proton-proton and heavy-ion collisions. Over the past few years, a wide variety of substructure observables have been proposed in order to understand specific aspects of jet dynamics in a quark-gluon plasma (QGP).
In this talk, based on , we will explore the ability of such an observable, called Dynamical Grooming , to pin down the properties of the QGP. In particular, we will present the computation via analytic resummation techniques and Monte-Carlo simulations, of the opening angle $\theta_g$ of the hardest splitting in the jet as defined by Dynamical Grooming. This calculation, grounded in perturbative QCD, accounts for the factorization in time between vacuum-like and medium-induced processes in the double logarithmic approximation.
Our main result is that the dominating scale in the $\theta_g$-distribution is the decoherence angle $\theta_c$ which characterizes the resolution power of the medium to propagating color probes, which makes this observable particularly interesting to measure $\theta_c$ experimentally. To that aim, we will highlight a suitable combination of the Dynamical Grooming condition and the jet radius that leads to a pQCD dominated observable with a very small sensitivity to medium response.
 P. Caucal, A. Soto-Ontoso and A. Takacs, arXiv:2111.14768
 Y. Mehtar-Tani, A. Soto-Ontoso and K. Tywoniuk, arXiv:1911.00375