Spin as a Probe into the Structure of the Universe

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It is now a well-established fact that nucleons, protons and neutrons, are made up of more elementary particles called quarks. The main physics program supported by this grant is to measure how the magnetic moments of quarks contribute to the total magnetic moment of the proton, along with contributions from other subatomic particles inside the proton. In addition, this grant will support research on an experiment at Fermi National Accelerator Laboratory, labeled E989, which will precisely measure the magnetic moment of a fundamental particle, the muon, which is like an electron but with more mass. The goal of these experiments is to compare experimental result with theoretical predictions from the so-called Standard Model of Particle Physics. The studies described here will provide graduate students with the necessary tools and knowledge to obtain post-doctoral work at other large colliders or smaller non-accelerator based collaborations. Undergraduate students funded by this award will continue to have the rare opportunity to experience the scientific culture and participate in experiments at National Laboratories.The studies of proton spin structure measurements will be carried out at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. Longitudinally and transversely polarized proton beams necessary for these experiments are only available at RHIC. Jet reconstruction techniques will be used to measure asymmetries sensitive to the gluon helicity and quark transversity distributions. This award will also support the new g-2 experiment (E989) at the Fermi National Accelerator Laboratory, which proposes to measure the muon anomalous magnetic moment to 0.14 parts per million. A deviation from the Standard Model prediction at the observed level could be explained by several Beyond the Standard Model (BSM) scenarios and the improved precision will significantly constrain key parameters in supersymmetry, one of the most widely discussed BSM models.