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The first measurement of heavy-flavour production by the LHCb experiment in its fixed-target mode is presented. The production of $J/psi$ and $D^0$ mesons is studied with beams of protons of different energies colliding with gaseous targets of helium and argon with nucleon-nucleon centre-of-mass energies of $sqrt{s_{NN}} = 86.6 $ and $ 110.4$ ${rm GeV}$, respectively. The $J/psi$ and $D^0$ (including charge conjugate) production cross sections in $p{rm He}$ collisions in the rapidity range $[2,4.6]$ are found to be $sigma_{J/psi} = 652 pm 33$ (stat) $pm 42$ (syst) nb$/$nucleon and $sigma_{D^0} = 80.8 pm 2.4$ (stat) $pm 6.3$ (syst) $mu$b$/$nucleon, where the first uncertainty is statistical and the second is systematic. No evidence for a substantial intrinsic charm content of the nucleon is observed in the large Bjorken-$x$ region.
By extracting the beam with a bent crystal or by using an internal gas target, the multi-TeV proton and lead LHC beams allow one to perform the most energetic fixed-target experiments ever and to study $pp$, $p$d and $p$A collisions at $sqrt{s_{NN}}=
We outline the opportunities for spin physics which are offered by a next generation and multi-purpose fixed-target experiment exploiting the proton LHC beam extracted by a bent crystal. In particular, we focus on the study of single transverse spin asymetries with the polarisation of the target.
We argue that the concept of a multi-purpose fixed-target experiment with the proton or lead-ion LHC beams extracted by a bent crystal would offer a number of ground-breaking precision-physics opportunities. The multi-TeV LHC beams will allow for the
In this note we provide a detailed derivation of the kinematic limit of the charm production in fixed-target experiments with the intrinsic charm coming from the target. In addition, we discuss the first measurement of charm quark production in the fixed-target configuration at the LHC.
AFTER@LHC is an ambitious fixed-target project in order to address open questions in the domain of proton and neutron spins, Quark Gluon Plasma and high-$x$ physics, at the highest energy ever reached in the fixed-target mode. Indeed, thanks to the h