Aperitivo Scientifico: AFTER@LHC : A fixed-target programme at the LHC for heavy-ion, hadron, spin and astroparticle physics

by Dr Jean-Philippe Lansberg (CNRS)

Sala seminari Astronomia, piano -1 (Dep. of Physics and Astronomy)

Sala seminari Astronomia, piano -1

Dep. of Physics and Astronomy

Via Ranzani 1
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