Physics at a Fixed-Target Experiment Using the LHC Beams
1IPN Orsay, Orsay, France
2Istituto Nazionale Di Fisica Nucleare, Roma, Italy
3CERN, Geneva, Switzerland
4Université de Liège, Liège, Belgium
5Czech Technical University, Prague, Czech Republic
Physics at a Fixed-Target Experiment Using the LHC Beams
Description
Fixed-target experiments (FTE) have brought essential contributions to particle and nuclear physics. They have led to particle discoveries (Ω, J/ψ, ϒ,...) and evidence for the novel dynamics of quarks and gluons in heavy-ion collisions. In accessing high xF and in offering options for (un-) polarised proton and nuclear targets, they have also led to the observation of surprising QCD phenomena. They offer specific advantages compared to collider experiments: access to high xF, high luminosities, target versatility, and polarisation.
The LHC 7 TeV protons on targets release a c.m.s. energy close to 115 GeV (72 GeV with Pb), in a range never explored so far, significantly higher than that at SPS and not far from RHIC. The production of quarkonia, DY, heavy flavours, jets, and γ in pA collisions can be studied with statistics previously unheard of and in the backward region, xF < 0, which is uncharted. High precision QCD measurements can also obviously be carried out in pp and pd collisions with H 2 and D 2 targets. With the 50 TeV protons of the future circular collider (FCC), the c.m.s. energy could reach 300 GeV for original studies of W and Z boson, and perhaps H 0, production in pp and pA collisions.
With the LHC Pb beam, one can study the quark-gluon plasma (QGP) from the viewpoint of the nucleus rest frame after its formation. Thanks to modern technologies, studies of, for instance, direct γ and quarkonium P-waves production in heavy-ion collisions can be envisioned.
Polarising the target allows one to study single-spin correlations including the Sivers effect, hence, the correlation between the parton k T and the nucleon spin.
We intend to publish a special issue on the physics at such a FTE using the LHC or FCC beams. The editors welcome original research articles and review articles from both theorists and experimentalists.
Potential topics include, but are not limited to:
- Heavy-quark and gluon content at large x
- TMDs and single-spin asymmetries
- Heavy-flavour studies in pA and AA collisions at FTEs
- W, Z, and H 0 production near threshold
- Target polarisation
- Secondary beams
- Simulation tools for high-energy physics
- Beam collimation and extraction with bent crystals
- Machine feasibility and radiological aspects
- Connection between UHECR studies and FTEs