Jean-Philippe Lansberg (CNRS)
In this seminar, I will review a number of recent ideas* put forward in favour of a fixed-target programme at the LHC – AFTER@LHC- dedicated to heavy-ion, hadron, spin and astroparticle physics. By using an internal (polarised) gas target or by extracting the beam with a bent crystal, the multi-TeV LHC beams allow one to perform the most energetic fixed-target experiments ever with which one can access the essentially uncharted backward kinematics with detectors similar to LHCb or ALICE.
In particular we argue that this allows one to study /pp/, /pd/ and /pA/ collisions at sqrt(s_NN) ≃ 115 GeV and Pb/p/ and Pb/A/ collisions at sqrt(s_NN) ≃72 GeV with extremely high precision with modern detection techniques. Such studies, including
– single transverse-spin asymmetries for hard and rare processes,
– suppression of heavy-flavours and quarkonia as well as azimuthal
asymmetries down to the target rapidity in heavy-ion collisions,
– cold-nuclear matter effects,
– the physics involved in ultra-peripheral hadron and ion collisions,
– far backward gluon and heavy-quark sensitive processes,
– vector-boson production near threshold …,
would greatly complement collider experiments, in particular those of the Electron-Ion Collider project or RHIC (with luminosities larger by 1 to 3 orders of magnitude).
Such a mode indeed allows for a broad physics programme, covering the large-/x/ QCD frontier for particle and astroparticle physics, as well as spin and heavy-ion physics with respectively a polarised target and the LHC lead beam.
*: for a complete list of references see
http://after.in2p3.fr/after/index.php/Recent_published_ideas_in_favour_of_AFTER@LHC