The LHCspin project: A polarized fixed target for LHC

A polarized fixed-target experiment at LHC will open the way for a broad and unique physics program. The kinematic coverage will allow studying the negative-rapidity region in the CM, corresponding to the poorly explored high $x$-Bjorken domain for the target proton. Furthermore, the use of a transversely polarized H or D gas will allow precision measurements of spin-asymmetries in Drell-Yan processes and in inclusive production of quarkonia, opening the way for the measurement of the unknown gluon PDFs, such as the gluon Sivers function. The status of the project, the R&D; for the implementation of the setup at the LHCb experiment, as well as the physics case, are discussed.