Using Muons and Protons to Probe the Structure of the Universe

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The primary physics program supported by this award is the precise measurement of the muon magnetic moment. The muon is a fundamental particle with characteristics very similar to the electron, but with 200 times the mass. The ultimate goal is to compare the experimental measurement with theoretical predictions from the so-called Standard Model of Particle Physics. The current Standard Model cannot explain many observed phenomena, such as the nature of dark matter or the origins of the matter-antimatter asymmetry in our universe. If discovered, a significant discrepancy between the experimental measurement and Standard Model predictions could provide long awaited insights into the nature of Beyond the Standard Model (BSM) physics. In addition, this award will support investigations into how quarks and gluons fragment into the matter that makes up our universe. It is now a well-established fact that protons are made up of more elementary particles, called quarks and gluons, that are bound tightly inside the proton. When liberated, the quarks and gluons break up and produce a shower of matter and antimatter particles. Measurements supported by this award will shed light on the number and characteristics of the particles produced in these showers. 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 muon measurements will be performed by the new g-2 collaboration at the Fermi National Accelerator Laboratory, which proposes to measure the muon anomalous magnetic moment to 140 parts per billion. A deviation from the Standard Model prediction at the observed level could be explained by several BSM scenarios and the improved precision will significantly constrain key parameters in supersymmetry, one of the most widely discussed BSM models. The studies of proton structure measurements will be carried out at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The root(s) = 200GeV proton collisions necessary for these experiments are only available at RHIC. Jet reconstruction techniques will be used to measure yields of identified pions, kaons and protons inside of fully reconstructed jets. These yields will provide critical input on gluon and quark transverse momentum dependent fragmentation functions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.