The present note relies on the recently published conceptual design report of the LHeC and extends the first contribution to the European strategy debate in emphasising the role of the LHeC to complement and complete the high luminosity LHC programme. The brief discussion therefore focuses on the importance of high precision PDF and $alpha_s$ determinations for the physics beyond the Standard Model (GUTs, SUSY, Higgs). Emphasis is also given to the importance of high parton density phenomena in nuclei and their relevance to the heavy ion physics programme at the LHC.
The LHeC is a proposed upgrade of the LHC to study $ep/eA$ collisions in the TeV regime, by adding a 60 GeV electron beam through an energy recovery linac. In $ep$, high precision top and electroweak physics can be performed, such as measurements of anomalous top couplings, light quark couplings to the $Z$ boson and the energy dependence of the weak mixing angle $sin^2!theta_W$, for which simulation studies are presented.
The Large Hadron-Electron Collider (LHeC) will operate at $sqrt{s}$ = 1.2 TeV and accumulate about 1/ab of integrated electron-proton luminosity. Novel studies of high energy photon-photon interactions at the LHeC, at the $gammagamma$ center-of-mass energy up to 1 TeV, will open new frontiers in the electroweak physics as well as in searches for physics beyond the Standard Model. Despite a very high $ep$ luminosity, the experimental conditions will be very favorable at the LHeC - a negligible event pileup will allow for unique studies of a number of processes involving the exclusive production via photon-photon fusion.
Particle and nuclear physics are moving toward a new generation of experiments to stress-test the Standard Model (SM), search for novel degrees of freedom, and comprehensively map the internal structure of hadrons. Due to the complex nature of QCD and wide array of past, present, and possible future experiments, measurements taken at these next-generation facilities will inhabit an expansive space of high-energy data. Maximizing the impact of each future collider program will depend on identifying its place within this sprawling landscape. As an initial exploration, we use the recently-developed PDFSense framework to assess the PDF sensitivity of two future high-energy facilities --- the high-luminosity upgrade to the LHC (HL-LHC) and the Large Hadron-electron Collider (LHeC) proposal --- as well as the electron-ion collider (EIC) proposed to map the few-GeV quark-hadron transition region. We report that each of these experimental facilities occupies a unique place in the kinematical parameter space with specialized pulls on particular collinear quantities. As such, there is a clear complementarity among these programs, with an opportunity for each to mutually reinforce and inform the others.
Permanent electric dipole moments (EDMs) of fundamental particles provide powerful probes for physics beyond the Standard Model. We propose to search for the EDM of strange and charm baryons at LHC, extending the ongoing experimental program on the neutron, muon, atoms, molecules and light nuclei. The EDM of strange Lambda baryons, selected from weak decays of charm baryons produced in pp collisions at LHC, can be determined by studying the spin precession in the magnetic field of the detector tracking system. A test of CPT symmetry can be performed by measuring the magnetic dipole moment of Lambda and anti-Lambda baryons. For short-lived Lambdac+ and Xic+ baryons, to be produced in a fixed-target experiment using the 7 TeV LHC beam and channeled in a bent crystal, the spin precession is induced by the intense electromagnetic field between crystal atomic planes. The experimental layout based on the LHCb detector and the expected sensitivities in the coming years are discussed.
The MoEDAL experiment at the LHC is optimised to detect highly ionising particles such as magnetic monopoles, dyons and (multiply) electrically charged stable massive particles predicted in a number of theoretical scenarios. MoEDAL, deployed in the LHCb cavern, combines passive nuclear track detectors with magnetic monopole trapping volumes (MMTs), while spallation-product backgrounds are being monitored with an array of MediPix pixel detectors. An introduction to the detector concept and its physics reach, complementary to that of the large general purpose LHC experiments ATLAS and CMS, will be given. Emphasis is given to the recent MoEDAL results at 13 TeV, where the null results from a search for magnetic monopoles in MMTs exposed in 2015 LHC collisions set the world-best limits on particles with magnetic charges more than 1.5 Dirac charge. The potential to search for heavy, long-lived supersymmetric electrically-charged particles is also discussed.