Speaker
Description
Experimental data on a wide range of jet observables measured in heavy-ion collisions provide strong constraints on the underlying medium dynamics and are addressed by state-of-the-art Monte Carlo models. However, so far there has been little theoretical guidance on the systematics of medium modifications on such diverse quantities as the inclusive jet spectrum, the intra-jet fragmentation functions and (groomed) substructure observables. We put forward a versatile and systematically improvable resummation framework for calculating jet observables that accounts for radiative and elastic energy loss [1,2,3]. This relies only on the separation of jet scales and medium scales that lead to the factorization of hard, early vacuum emissions and soft, medium-induced branchings [1,4]. As three concrete examples, we discuss the a) inclusive jet spectrum for different radii [2], b) the distribution of microjets/hadrons inside large jets, and c) the jet mass in heavy-ion collisions. Tuning the medium parameters to the nuclear modification factor of inclusive jets simultaneously provides a baseline modification of the fragmentation function as well as the shift and distortion of the jet mass peak. This program grants, on one hand, a powerful framework to consistently study modifications of jets across a wide range of observables (with a grip on their resilience to non-perturbative effects) and, on the other hand, furnishes access to the value of the coupling between individual jet color charges with the underlying medium.
[1] Y. Mehtar-Tani and K. Tywoniuk, "Sudakov suppression of jets in QCD media," Phys.Rev.D 98 (2018) 051501 [arXiv:1707.07361 [hep-ph]].
[2] Y. Mehtar-Tani, D. Pablos and K. Tywoniuk, "Cone size dependence of jet suppression in heavy-ion collisions," (accepted for publication in Phys.Rev.Lett.) [arXiv:2101.01742 [hep-ph]].
[3] Y. Mehtar-Tani and K. Tywoniuk, in preparation
[4] P. Caucal, E. Iancu, A. H. Mueller and G. Soyez, "Vacuum-like jet fragmentation in a dense QCD medium," Phys.Rev.Lett. 120 (2018) 232001 [arXiv:1801.09703 [hep-ph]].
