The LHeC:
Deep Inelastic Electron-Nucleon Scattering at the LHC
Deep Inelastic Electron-Nucleon Scattering at the LHC
Interim report to ECFA (30/11/09, M Klein) is here
The LHeC is a proposed colliding beam facility at CERN, which will exploit the new world of energy and intensity provided by the LHC for lepton-nucleon scattering.
An existing 7 TeV LHC proton or heavy ion beam will collide with a new electron beam simultaneously with proton-proton or heavy ion collisions taking place at the existing LHC experiments.
Two possibilities are being pursued for the electron beam. In the first, it circulates in the existing LHC tunnel with a nominal energy of 50 GeV, resulting in an unprecedented kinematic range for lepton-nucleon scattering: the centre of mass energy of 1.2 TeV is 4 times larger than the previous highest at HERA. The luminosity of over 1033 cm-2s-1 is two orders of magnitude larger than previous similar proposals. An alternative solution is an electron linac, resulting in reduced luminosities, but larger centre of mass energies (nominally 2 TeV).
The large energy and luminosity make the LHeC uniquely sensitive to the direct single production of massive new electron-quark bound states and to other new physics, for example via selectron-squark production. It also allows the parton densities of the proton to be measured at previously unexplored momentum transfers (Q2 beyond 106 GeV2) and small fractional momenta (Bjorken x below 10-6 for Q2 = 1 GeV2), well matched to the range required for a full understanding of proton-proton collisions on the LHC rapidity plateau. The newly accessed low x region is the ideal laboratory in which to search for novel strong interaction dynamics in an environment of extremely high parton densities, but with small enough strong coupling to apply perturbative methods.