We report on the studies of Transverse-Momentum-Dependent distributions (TMDs) at a future fixed-target experiment --AFTER@LHC-- using the p+ or Pb ion LHC beams, which would be the most energetic fixed-target experiment ever performed. AFTER@LHC opens new domains of particle and nuclear physics by complementing collider-mode experiments, in particular those of RHIC and the EIC projects. Both with an extracted beam by a bent crystal or with an internal gas target, the luminosity achieved by AFTER@LHC surpasses that of RHIC by up to 3 orders of magnitude. With an unpolarised target, it allows for measurements of TMDs such as the Boer-Mulders quark distributions and the distribution of unpolarised and linearly polarised gluons in unpolarised protons. Using polarised targets, one can access the quark and gluon Sivers TMDs through single transverse-spin asymmetries in Drell-Yan and quarkonium production. In terms of kinematics, the fixed-target mode combined with a detector covering ηlab∈[1,5] allows one to measure these asymmetries at large x↑ in the polarised nucleon.
@article{arxiv.1502.00984,
title = {Studies of Transverse-Momentum-Dependent distributions with A Fixed-Target ExpeRiment using the LHC beams (AFTER@LHC)},
author = {L. Massacrier and M. Anselmino and R. Arnaldi and S. J. Brodsky and V. Chambert and W. den Dunnen and J. P. Didelez and B. Genolini and E. G. Ferreiro and F. Fleuret and Y. Gao and C. Hadjidakis and I. Hrivnacova and J. P. Lansberg and C. Lorcé and R. Mikkelsen and C. Pisano and A. Rakotozafindrabe and P. Rosier and I. Schienbein and M. Schlegel and E. Scomparin and B. Trzeciak and U. I. Uggerhoj and R. Ulrich and Z. Yang},
journal= {arXiv preprint arXiv:1502.00984},
year = {2016}
}