26th International Symposium on Spin Physics (SPIN2025)

A polarized gaseous target, operated in combination with the high-energy and high-intensity LHC beams, has the potential to open new physics frontiers and to deepen our understanding of the strong interaction in the non-perturbative regime of QCD. Specifically, the LHCspin project aims to perform spin-physics studies in high-energy polarized fixed-target collisions using the LHCb detector. Being designed and optimized for the detection of heavy hadrons, LHCb will allow to probe the nucleon structure through, e.g., the inclusive production of c- and b-hadrons, and ideal tool to access the essentially unexplored spin-dependent gluon TMDs. This configuration will allow to explore the nucleon internal dynamics at unique kinematic conditions, including the poorly explored high x-Bjorken and high x-Feynman regimes. With the installation of the proposed setup, LHCb will become the first experiment delivering simultaneously unpolarized beam-beam collisions at 14 TeV and both polarized and unpolarized beam-target collisions at center-of-mass energies of the order of 100 GeV. The current status of the LHCspin project is presented, with a focus on the anticipated timeline for its experimental implementation.

The muon magnetic anomaly, $a_\mu = (g-2)/2$, can be both measured and computed to a very high precision, making it a powerful probe to test the Standard Model of particle physics and search for new physics. The Fermilab Muon g-2 Collaboration has recently released the third and final measurement of the magnetic anomaly of the positive muon. The measurement shows excellent agreement with the previous measurements and with the previous E821 experiment at Brookhaven (USA). The final record-breaking precision of 127 parts per billion (ppb) surpassed the initial design goal of the experiment. This achievement was possible thanks to both high statistics and to the extensive and scrupolous analysis of the magnetic fields, the beam dynamics, and the particle detection, obtaining a final systematic uncertainty under 80 ppb. This talk will cover the highlights of the latest measurement, discuss its comparison with the latest Standard Model predictions, and provide an outlook on the upcoming analyses.

The research addresses two fundamental questions in particle physics and cosmology: the fate of antimatter after the Big Bang and the nature of Dark Matter (DM). Its focus lies on the study of Electric Dipole Moments (EDMs) in particles such as protons and deuterons, explored through polarized particle beams stored in a dedicated ring.

Up to now, experimental efforts have been carried out at the COoler SYnchrotron (COSY) storage ring at Forschungszentrum Jülich in Germany, which ceased operations at the end of 2023. The next step foresees the design and construction of a Prototype Storage Ring (PSR), in both all-electric and hybrid (electric and magnetic) configurations, operating at beam energies of 30–45 MeV with a circumference of about 100 meters. The PSR will serve as a testbed to resolve key technical challenges and pave the way toward a full-scale EDM facility dedicated to precise proton EDM measurements.

In the subsequent phase, a high-precision EDM facility with 233 MeV beam energy and a circumference of approximately 500 meters will be developed. This installation is expected to push the current sensitivity limits of the neutron’s static EDM to unprecedented levels, potentially enabling groundbreaking discoveries in our understanding of the fundamental symmetries of nature.