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

Photon-tagged measurements of jet quenching with the ATLAS detector

May 16, 2018, 9:20 AM
Sala Perla, 1st Floor (Palazzo del Casinò)

Sala Perla, 1st Floor

Palazzo del Casinò

Parallel Talk Jet modifications and high-pT hadrons Jet modifications and high-pT hadrons


Dennis Perepelitsa (University of Colorado Boulder)


Events containing a high transverse momentum ($p_\mathrm{T}$) prompt photon offer a useful tool to study the dynamics of the hot, dense medium produced in heavy ion collisions. Because photons do not carry color charge, they are unaffected by the medium, and thus provide information about the momentum, direction, and flavor (quark or gluon) of the associated hard-scattered parton before it begins to shower and become quenched. In particular, the presence of a high-$p_\mathrm{T}$ photon can be used to select $pp$ and Pb+Pb events with the same configuration before quenching, limiting the effects of selection biases present in other jet measurements. The large statistics $pp$ and Pb+Pb data delivered by the LHC in 2015 thus allow for a detailed study of photon-tagged jet quenching effects, such as the overall parton energy loss and modified structure of the component of the shower which remains correlated with the initial parton direction (e.g. in cone). These can be explored as a function of photon $p_\mathrm{T}$, centrality, and reaction plane. In this talk, the latest status of photon-tagged jet measurements in ATLAS will be presented, including a new measurement of how the fragmentation function for jets in photon-tagged events is modified. This measurement in particular reveals a non-trivial difference relative to the analogous observable for inclusive jets.

Content type Experiment
Collaboration ATLAS
Centralised submission by Collaboration Presenter name already specified

Primary author

Barbara Krystyna Wosiek (Institute of Nuclear Physics Polish Academy of Sciences (PL))

Presentation materials