LHCspin - A polarised target for the LHC

Abstract:

The state of art in the field of particle physics is still based on a 1-Dimensional description of the hadrons internal structure and in particular of protons and neutrons. The investigation of the subatomic structure, and the field of particle physics at large, can be revolutionized by providing 3D description of the hadron structure. This detailed knowledge has the enormous potential to significantly deepen our understanding of strong interactions, and the possibility to provide a much more accurate framework for measurements of the Standard Model and Beyond observables. Three key ingredients to achieve this level of knowledge are a high-luminosity high-energy accelerator, a very performing particle detector, and a highly polarized target.
The goal of LHCspin is to develop, in the next few years innovative solutions and cutting-edge technologies to measure the 3D structure of nucleons in high-energy polarized fixed-target collisions, by exploring a unique kinematic regime and by exploiting new reaction processes.
This ambitious task poses its basis on the recent installation of an unpolarized gas target in front of the LHCb spectrometer. Specifically, the unpolarized target, already itself a groundbreaking project, will allow to carefully study the dynamics of the beam-target system and clarify the potentiality of the entire system, as the basis for an outstanding and innovative physics program at the LHC. With the instrumentation of the proposed target system, LHCb will become the first experiment delivering simultaneously unpolarized beam-beam at √s=14 TeV and polarized and unpolarized beam-target collisions at √sNN~100 GeV. LHCspin could open new physics frontiers exploiting the potential of the existent most powerful collider and of one of the most advanced detectors. The importance of such a new colliding system has been highlighted in the summary of the European Strategy and by the CERN committee Physics Beyond Colliders.
An experiment with these characteristics has the potential to provide a great impact on different research fields that extends well beyond the study of nucleon structure and strong force. For instance, relevant by-products are the development of the technology for the realization of an optimal internal coating of beam pipes (in our case the storage cell), detailed studies of the machine-target interactions in terms of beam aperture and impedance issues, and study of depolarization phenomena in the framework of a high energy and high luminosity collider, all fundamental aspects relevant for the R&D of future colliders.