# Quark Matter 2018

13-19 May 2018
Venice, Italy
Europe/Zurich timezone
The organisers warmly thank all participants for such a lively QM2018! See you in China in 2019!

## Resolution Effects in the Hybrid Strong/Weak Coupling Model

15 May 2018, 17:00
2h 40m
First floor and third floor (Palazzo del Casinò)

### First floor and third floor

#### Palazzo del Casinò

Poster Jet modifications and high-pT hadrons

### Speaker

Zachary Hulcher (Cambridge University)

### Description

Within a hybrid strong/weak coupling model of jet quenching, plasma produced in a heavy ion collision cannot resolve the substructure of a collimated parton shower propagating through it with arbitrarily fine spatial resolution. We introduce a screening length parameter, $L_{res}$, proportional to the inverse of the local temperature in the plasma, estimating a range for the value of the proportionality constant via comparing weakly coupled QCD calculations and holographic calculations appropriate in strongly coupled plasma. When a parton in a jet splits, its two offspring are initially unresolved and suffer the energy loss of the original parton until they are separated by $L_{res}$. This delays the quenching of partons with intermediate energy, resulting in the survival of more hadrons in the final state with $p_T$ in the several GeV range. Introducing a nonzero $L_{res}$ results in modifications to the jet shapes and jet fragmentations functions, as it makes it more probable for particles carrying a small fraction of the jet energy at larger angles from the jet axis to survive their passage through the quark-gluon plasma. These effects are small in magnitude, which we confirm via checking for effects on missing-$p_T$ observables.

Content type Theory Presenter name already specified

### Primary authors

Zachary Hulcher (Cambridge University) Daniel Pablos (Universitat de Barcelona) Krishna Rajagopal (Massachusetts Inst. of Technology (US))