Probing QCD matter with jets - towards more differential observables.
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Probing non-trivial properties of the QCD matter produced in heavy-ion collisions - flow, anisotropies, medium backreaction, etc - with high-energy jets requires one to go beyond standard jet substructure observables. First, it would be desirable to calculate more differential observables inside jets, e.g., with a dependence on the azimuthal distribution or with a sensitivity to final state spin polarisation. Then, novel observables probing energy correlations inside jets are a promising avenue to cleanly isolate specific perturbative modifications imprinted on jets.
In this talk, I will discuss some recent and on-going work in these directions. In particular, I will show that a simple model for matter anisotropy - an axis-dependent quenching - imprints a non-trivial azimuthal dependence on the spectrum of quark pair production and that this effects couples to the spin polarisation of the final state. I will discuss how this azimuthal dependence can be studied in double differential energy-correlators. Further, I will examine what one can learn by going beyond two particles in the final state inside a medium. In this sense, I will present analytic results for the three-point energy-correlator and projected n-point energy-correlators with both perturbative modifications to the jet and the hydrodynamics-like response from the medium included. Importantly, I will also address how the effect of collinear spin correlations, manifested as an azimuthal pattern of interference, is modified by the presence of an isotropic/anisotropic medium.
