22-27 September 2016
East Lake International Conference Center
Asia/Chongqing timezone
<a href="http://hp2016.ccnu.edu.cn">http://hp2016.ccnu.edu.cn</a>

Measurements of photon+jet production in 5 TeV pp and Pb+Pb collisions with the ATLAS detector

24 Sep 2016, 16:20
Shi-Yan Hall (East Lake International Conference Center)

Shi-Yan Hall

East Lake International Conference Center

Donghu Road 142, Wuchang District, Wuhan, Hubei, China


Brian Cole (Columbia University (US))


Measurements of prompt high-pT photon and associated jet production are a valuable way to explore how fast partons lose energy in the hot, deconfined medium created in relativistic heavy ion collisions. Since the photon pT is approximately balanced by the initial parton pT at leading order, these events can provide insight on how energy loss depends on the parton pT before quenching. Additionally, the leading jets in these events are likely to be quark-initiated. Thus, together with measurements of inclusive jet suppression, they may also provide a handle on the parton flavor dependence of energy loss. Photon+jet production measurements in the LHC Run 1 data showed that the jet-to-photon pT balance ratio, xJg = pTjet/pTphoton, and the per-photon jet yield, RJg, are systematically suppressed in more central collisions, while the photon+jet azimuthal correlation, Delta-phi, is unmodified. In the higher-luminosity, higher-collision-energy LHC Run 2 data, photon+jet events can be explored with greater statistical precision and in a more differential manner. In this analysis, events containing an isolated photon with pT > 60 GeV are studied in 520/ub and 26/pb of 5 TeV Pb+Pb and pp collision data. Measurements by ATLAS of xJg, RJg, and Delta-phi are presented in pp collisions and as a function of centrality in Pb+Pb collisions.

Presentation type Oral

Primary author

Brian Cole (Columbia University (US))

Presentation Materials