Investigating the Role of Coherence Effects on Jet Quenching in Pb-Pb Collisions at sNN=2.76\sqrt{s_{NN}} =2.76 TeV using Jet Substructure

We report measurements of two jet shapes, the ratio of 2-Subjettiness to 1-Subjettiness ($\it{\tau_{2}}/\it{\tau_{1}}$) and the opening angle between the two axes of the 2-Subjettiness jet shape, which is obtained by reclustering the jet with the exclusive-$\it{k}_{T}$ algorithm~\cite{kT} and undoing the final clustering step. The aim of this measurement is to explore a possible change in the rate of 2-pronged objects in Pb-Pb compared to pp due to colour coherence. Coherence effects~\cite{ColourCoherence} relate to the ability of the medium to resolve a jet's substructure, which has an impact on the energy loss magnitude and mechanism of the traversing jet. In both collision systems charged jets are found with the anti-$\it{k}_{T}$ algorithm~\cite{Anti-kT}, a resolution parameter of $\it{R}=$0.4\ and a constituent cut off of $0.15$ GeV. This analysis uses hadron-jet coincidence techniques in Pb-Pb collisions to reject the combinatorial background and corrects further for background effects by employing various jet shape subtraction techniques and two dimensional unfolding. Measurements of the Nsubjettiness for jet momenta of $40-60$ GeV/$\it{c}$ in Pb-Pb collisions at $\sqrt{s_{NN}} =2.76$ TeV and pp collisions at $\sqrt{s} =7$ TeV will be presented and compared to PYTHIA simulations.Comment: 4 pages, 5 figures, QM2017 Proceeding

Entanglement at a Scale and Renormalization Monotones

We study the information content of the reduced density matrix of a region in quantum field theory that cannot be recovered from its subregion density matrices. We reconstruct the density matrix from its subregions using two approaches: scaling maps and recovery maps. The vacuum of a scale-invariant field theory is the fixed point of both transformations. We define the entanglement of scaling and the entanglement of recovery as measures of entanglement that are intrinsic to the continuum limit. Both measures increase monotonically under the renormalization group flow. This provides a unifying information-theoretic structure underlying the different approaches to the renormalization monotones in various dimensions. Our analysis applies to non-relativistic quantum field theories as well the relativistic ones, however, in relativistic case, the entanglement of scaling can diverge