Simulating Photon-Triggered Jets in Quark-Gluon Plasma: Results and Discussion

4 Sept 2024

Authors:

(1) Chathuranga Sirimanna, Department of Physics, Duke University, Durham, Department of Physics and Astronomy, Wayne State University, Detroit, and for the JETSCAPE Collaboration;

(2) Yasuki Tachibana, Akita International University, Yuwa, Akita-city 010-1292, Japan and for the JETSCAPE Collaboration.

Table of Links

Abstract and 1 Introduction

2 Simulating photon triggered jets using JETSCAPE framework

3 Results and Discussion, Acknowledgments, and References

3 Results and Discussion

Since CMS results for both p-p and Pb-Pb are smeared, the same smearing function is applied for a proper comparison, as illustrated in Figure 3. Similarly, in this case, results from full events exhibit better agreement with the experimental results. Although the isolated photons mainly consist of prompt photons, these findings suggest a significant contribution to the transverse momentum imbalance from other photons, including those produced in the partonic shower and fragmentation photons.

Figure 1. γ-jet asymmetry for p-p collisions using prompt-photon events and full events generated by JETSCAPE compared with ATLAS results. Here four pTγ regions from 63.1GeV to 200GeV are used.

Figure 2. γ-jet asymmetry for Pb-Pb collisions using prompt-photon events and full events generated by JETSCAPE compared with ATLAS results. Same pTγ regions as Figure 1 is used here.

Figure 3. γ-jet asymmetry for p-p and Pb-Pb (0-10%) collisions using prompt-photon events and full events generated by JETSCAPE compared with CMS results. Here both p-p and Pb-Pb distributions are smeared according to the smearing function for 0-10% centrality.

JETSCAPE results for the majority of photon-triggered jet observables provide an excellent description of the experimental results without requiring additional parameter tuning. While current theoretical knowledge is insufficient to fully understand certain observables like isolated photon and multi-jet correlation, JETSCAPE, with its multistage evolution, offers an excellent description of all stages of jet evolution — a significant improvement over single-stage jet evolution. This analysis was conducted without further modification of the previous PP19 and AA22 parameter tunes. Therefore, this study serves as a parameter-free verification of multistage evolution.

Figure 4. zg distribution using photon-triggered jets calculated for four different XJγ regions by using prompt-photon events generated by JETSCAPE.

Figure 5. Isolated photon and di-jet correlation, xJJγ calculated using prompt-photon events generated by JETSCAPE compared with ATLAS preliminary results [7].

Acknowledgments

These proceedings are supported in part by the National Science Foundation (NSF) within the framework of the JETSCAPE collaboration, under grant numbers ACI-1550300 OAC2004571 (CSSI:X-SCAPE) and in part by the U.S. Department of Energy (DOE) under grant number DE-SC0013460.

References

[1] X.N. Wang, Z. Huang, I. Sarcevic, Phys. Rev. Lett. 77, 231 (1996), hep-ph/9605213

[2] A. Kumar et al. (JETSCAPE), Phys. Rev. C 102, 054906 (2020), 1910.05481

[3] A. Kumar et al. (JETSCAPE), Phys. Rev. C 107, 034911 (2023), 2204.01163

[4] C. Sirimanna (JETSCAPE), PoS HardProbes2020, 051 (2021), 2009.04407

[5] M. Aaboud et al. (ATLAS), Phys. Lett. B 789, 167 (2019), 1809.07280

[6] A.M. Sirunyan et al. (CMS), Phys. Lett. B 785, 14 (2018), 1711.09738

[7] Tech. rep., CERN, Geneva (2023), all figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/CONFNOTES/ATLASCONF-2023-008, https://cds.cern.ch/record/2854837

This paper is available on arxiv under CC BY 4.0 DEED license.