17 Bailhache, Raphaelle Bonocore, D. Braun-Munzinger, Peter Feal, X. Floerchinger, S. Klein, J. Köhler, K. Lebiedowicz, P. Peter, C. M. Rapp, R. Reygers, K. Schäfer, W. Scheid, H. S. Schweda, Kai Stachel, Johanna van Hees, H. van Veen, C. A. Völkl, M. EXM ALI Physics reports Physics reports Elsevier Science, North-Holland Amsterdam [u.a.] 0370-1573 10.1016/j.physrep.2024.10.002 English 1-40 1097 This report summarizes the work of the EMMI Rapid Reaction Task Force on “Real and Virtual Photon Production at Ultra-Low Transverse Momentum and Low Mass at the LHC”. We provide an overview of the soft-photon puzzle, i.e., of the long-standing discrepancy between experimental data and predictions based on Low’s soft-photon theorem, also referred to as “anomalous” soft photon production, and we review the current theoretical understanding of soft radiation and soft theorems. We also focus on low-mass dileptons as a tool for determining the electrical conductivity of the medium produced in high-energy nucleus–nucleus collisions. We discuss how both topics can be addressed with the planned ALICE 3 detector at the LHC. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). ; PUB:(DE-HGF)16, ; 0, ; WOS:001342368500001 Journal Article 2024 GSI-2025-00294 2024 https://repository.gsi.de/record/356916 https://doi.org/10.1016/j.physrep.2024.10.002 <Go to ISI>://WOS:001342368500001