Andre, K. D. J.Bella, L. AperioArmesto, N.Bogacz, S. A.Britzger, D.Bruening, O. S.D'Onofrio, M.Ferreiro, E. G.Fischer, O.Gwenlan, C.Holzer, B. J.Klein, M.Klein, U.Koçak, FatmaKostka, P.Kumar, M.Mellado, B.Milhano, J. G.Newman, P. R.Piotrzkowski, K.Polini, A.Ruan, X.Russenschuk, S.Schwanenberger, C.Vilella-Figueras, E.Yamazaki, Y.2024-12-032024-12-032022-01-011434-6044https://doi.org/10.1140/epjc/s10052-021-09967-zhttps://link.springer.com/article/10.1140/epjc/s10052-021-09967-zhttps://ora.ox.ac.uk/objects/uuid:037acb98-e8ff-431a-9a95-03aca0797473/files/sns064682mhttps://hdl.handle.net/11452/48825Novel considerations are presented on the physics, apparatus and accelerator designs for a future, luminous, energy frontier electron-hadron (eh) scattering experiment at the LHC in the thirties for which key physics topics and their relation to the hadron-hadron HL-LHC physics programme are discussed. Demands are derived set by these physics topics on the design of the LHeC detector, a corresponding update of which is described. Optimisations on the accelerator design, especially the interaction region (IR), are presented. Initial accelerator considerations indicate that a common IR is possible to be built which alternately could serve eh and hh collisions while other experiments would stay on hh in either condition. A forward-backward symmetrised option of the LHeC detector is sketched which would permit extending the LHeC physics programme to also include aspects of hadron-hadron physics. The vision of a joint eh and hh physics experiment is shown to open new prospects for solving fundamental problems of high energy heavy-ion physics including the partonic structure of nuclei and the emergence of hydrodynamics in quantum field theory while the genuine TeV scale DIS physics is of unprecedented rank.eninfo:eu-repo/semantics/openAccessDeep-inelastic scatteringKinematic reconstructionH1 experimentQcdCalorimeterPhysicsScience & technologyPhysical sciencesPhysics, particles & fieldsArticle00074292790000182110.1140/epjc/s10052-021-09967-z1434-6052