Jet Shapes of Isolated Photon-Tagged Jets in Pb-Pb and pp Collisions at sNN=5.02  TeV

Abstract

The modification of jet shapes in PbPb collisions, relative to those in pp collisions, is studied for jets associated with an isolated photon. The data were collected with the CMS detector at the LHC at a nucleon-nucleon center-of-mass energy of 5.02 TeV.

A complete set of in-medium splitting functions to any order in opacity

“…The derivation and numerical evaluation of higher order in opacity corrections is important and timely, as their real application is in medium-induced splitting kernels that enter the calculation of fixed order and resummed observables involving reconstructed jets. Corresponding to the changes we see in the more differential splitting functions, we anticipate that the greatest phenomenological impacts will be on the interpretation of jet substructure measurements in heavy ion collisions [24][25][26][27][28][29][30][31]. Even in more inclusive observables, such as the suppression of jet production denoted R AA , we anticipate the second order in opacity corrections to play a role, albeit milder.…”

Jet charge modification in finite QCD matter

“…The medium modified jet charge is calculated from Eq. (17). Figure 3 This brings us to an important proposed measurement that we present in Figure 4 -the modification of individual flavor jet charge in heavy-ion versus proton collisions.…”

“…Initial studies focused on the momentum imbalance distribution of vector boson-tagged jets in nucleusnucleus (A+A) relative to the proton-proton (p+p) collisions [8][9][10][11][12][13][14][15]. More recently, the jet substructure modification of photon-tagged predominantly quark jets has been compared to the corresponding modification of inclusive jets [16][17][18]. Ultimately, we would like to understand the modification of individual flavor jets, such as up-quark jets or down-quark jets.…”

Shining a Light on the QGP - Electroweak Probes Experimental Summary

“…Additionally, these collaborations presented the corresponding results in Au-Au collisions at the same √ s NN , which strongly indicate a redistribution of the recoiling jet energy towards large angles. Furthermore, the ATLAS and CMS collaborations presented their recent multi-differential results on the isolated-photon jet tagged measurements [57][58][59][60] at high p T . When measuring the γ-jet p Tbalance distributions in multiple centrality classes the ATLAS collaboration observed a significant broadening of the x jγ distribution in central Pb-Pb events with an isolated photon and a recoiling leading jet (Figure 4 (left)).…”

“…The broadening increases further when considering all jets in the γ- [58]. Right: Ratio of the differential jet shape ρ(r) for jets associated with an isolated photon with a p T above 60 GeV/c for 0-10% central Pb-Pb and pp collisions at √ s NN = 5.02 TeV compared to different theory calculations [59].…”