LHCb Fixed-target results and prospects

Abstract

Among the LHC experiments, LHCb has, starting from 2015, the unique possibility to exploit the injection of noble gases into the LHC accelerator to acquire in fixed-target configuration the collisions between protons or lead ions and gas atoms. These give access to poorly-constrained kinematic regions and provide an example of extending the diversity of the LHC physics reach, stressed as a key requirement for the future in the 2020 update of the European strategy for Particle Physics. Two examples of analyses alsomotivated by open problems in the cosmic rays community and the respective ongoing extensions are reviewed: the first charm production measurement at fixed-target LHC in the pHe and pAr systems withsNN = 87 GeV and √ sNN = 110 GeV nucleonnucleon centre-of-mass energies, respectively, and the first determination of the prompt antiproton production cross-section in pHe collisions at sNN = 110 GeV. The fixed-target system is now being upgraded with the installation of a confinement cell for the gas upstream the nominal beambeam interaction point. The gas areal density will be increased by up to two orders of magnitude, also non-noble gases like oxygen and hydrogen could be injected and the separation between the beam-beam and beam-gas collision regions will open the possibility to simultaneously operate the LHCb detector in collider and fixed-target mode. All of this will result in a unique laboratory for QCD studies at the LHC.