The Large Hadron-Electron Collider at the HL-LHC

The Large Hadron-Electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy-recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High-Luminosity Large Hadron Collider (HL-LHC). The accelerator and interaction region are designed for concurrent electron-proton and proton-proton operations. This report represents an update to the LHeC's conceptual design report (CDR), published in 2012. It comprises new results on the parton structure of the proton and heavier nuclei, QCD dynamics, and electroweak and top-quark physics. It is shown how the LHeC will open a new chapter of nuclear particle physics by extending the accessible kinematic range of lepton-nucleus scattering by several orders of magnitude. Due to its enhanced luminosity and large energy and the cleanliness of the final hadronic states, the LHeC has a strong Higgs physics programme and its own discovery potential for new physics. Building on the 2012 CDR, this report contains a detailed updated design for the energy-recovery electron linac (ERL), including a new lattice, magnet and superconducting radio-frequency technology, and further components. Challenges of energy recovery are described, and the lower-energy, high-current, three-turn ERL facility, PERLE at Orsay, is presented, which uses the LHeC characteristics serving as a development facility for the design and operation of the LHeC. An updated detector design is presented corresponding to the acceptance, resolution, and calibration goals that arise from the Higgs and parton-density-function physics programmes. This paper also presents novel results for the Future Circular Collider in electron-hadron (FCC-eh) mode, which utilises the same ERL technology to further extend the reach of DIS to even higher centre-of-mass energies.Peer reviewe

Recent H1 Results on Diffraction

Latest results from the H1 experiment on diffractive processes at HERA are presented. They cover inclusive measurements of diffractive deep inelastic scattering, as well as diffractive dijet production both in DIS and photoproduction regimes. Inclusive cross sections are measured based on the large statistics sample selected by the Large Rapidity Gap technique. Dijet final states are studied by using diffractive samples with tagged leading proton.Experimental data are compared to several theoretical models and to NLO QCD calculations using diffractive parton densities. Factorisation properties of diffractive ep scattering are teste

New HERA Results on Diffraction

Four new measurements are presented from the area of diffractive and exclusive production at HERA. Preliminary results are available for isolated photons in diffractive photoproduction from ZEUS and open charm cross section in diffractive deep-inelastic scattering (DIS) regime from H1. ZEUS Collaboration has also measured the cross-section ratio $\it \sigma_{\psi (2S )}/\sigma J/\psi (1S )$ in exclusive DIS using full HERA data statistics. Finally, H1 Collaboration for the first time studied exclusive $\rho^{0}$ meson photoproduction associated with a leading neutron at HERA