engBailhache, RaphaelleBonocore, D.Reygers, K.Schäfer, W.Scheid, H. S.Schweda, KaiStachel, Johannavan Hees, H.van Veen, C. A.Völkl, M.Braun-Munzinger, PeterFeal, X.Floerchinger, S.Klein, J.Köhler, K.Lebiedowicz, P.Peter, C. M.Rapp, R.Anomalous soft photons: Status and perspectivesinfo:eu-repo/classification/ddc/530This 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.Physics reports 1097, 1-40 (2024). doi:10.1016/j.physrep.2024.10.002info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionElsevier Science, North-Holland2024info:eu-repo/semantics/openAccessDEhttps://repository.gsi.de/record/356916https://repository.gsi.de/search?p=id:%22GSI-2025-00294%22Researchersinfo:eu-repo/semantics/altIdentifier/wos/WOS:001342368500001info:eu-repo/semantics/altIdentifier/arxiv/arXiv:2406.17959info:eu-repo/semantics/altIdentifier/issn/0370-1573info:eu-repo/semantics/altIdentifier/doi/10.15120/GSI-2025-00294info:eu-repo/semantics/altIdentifier/doi/10.1016/j.physrep.2024.10.002