The axion is a well-motivated dark matter candidate, but is challenging to search for. We propose a new way to search for QCD axion and axion-like-particle (ALP) dark matter. Nuclei that are interacting with the background axion dark matter acquire time-varying CP-odd nuclear moments such as an electric dipole moment. In analogy with nuclear magnetic resonance, these moments cause precession of nuclear spins in a material sample in the presence of a background electric field. This precession can be detected through high-precision magnetometry. With current techniques, this experiment has sensitivity to axion masses below 10^-9 eV, corresponding to theoretically well-motivated axion decay constants around the grand unification and Planck scales. With improved magnetometry, this experiment could ultimately cover the entire range of masses below 10^-6 eV, just beyond the region accessible to current axion searches. A discovery in such an experiment would not only reveal the nature of dark matter and confirm the axion as the solution of the strong CP problem, but would also provide a glimpse of physics at the highest energy scales, far beyond what can be directly probed in the laboratory.
Through Paul Laurence Dunbar High School's Math, Science, and Technology Center, high school senior Valerie Sarge is acquiring an impressive set of research skills before she even begins college. Valerie has been working with chemistry professor John Anthony at UK's Center for Applied Energy Research, and is looking at how agricultural byproducts might be able to be used in flexible, low-cost electronics.
The Proton's Weak Charge One of the highest priorities of present-day experimental particle and nuclear physics is to search for indications of physics which is not contained in the Standard Model. Precision measurements of quantities that are robustly predicted within the Standard Model are an important class of such searches. An example is a measurement of the proton's weak charge. The weak charge is the strength of the proton's vector coupling to the weak neutral current, and its value is a firm prediction of the Standard Model. Thus an experimental test of the prediction is well motivated as a search for new physics. A recently completed experiment at Jefferson Lab, Qweak, has the goal of making the first precision measurement of the weak charge, using parity-violating electron scattering from hydrogen at very low momentum transfer. The result from the first subset of data will be presented, as well as an overview of the data analysis for the full data set and prospects for the final result, which will provide a sensitivity to new physics at the multi-TeV scale.
The College of Arts & Sciences at the University of Kentucky offers the opportunity to work with renowned faculty in over forty varied departments. From Economics to Earth and Environmental Studies, A&S offers a hands-on educational experience, preparing you for a successful career after graduation.
THE ABSTRACT Neutrinoless double beta decay (0νββ) is a beyond-the-standard-model physics process in which a nucleus (A,Z) decays to (A,Z+2) with the emission of two electrons (but no neutrinos). Experimental searches for 0νββ are motivated by the access this process gives to testing any Majorana nature of neutrinos and lepton number non-conservation. This process is also a sensitive probe of the absolute neutrino mass scale. EXO (Enriched Xenon Observatory) is an experimental program searching for 0νββ decay of 136Xe. The first phase of the program, EXO-200, uses 200 kg of Xenon enriched to 80% in 136Xe, liquefied in a Time Projection Chamber (TPC) with scintillation readout (100 kg active mass), allowing for event calorimetry and 3D localization of ionizing events. EXO-200 has found the standard two-neutrino decay mode 2νββ of 136Xe, and has made a precision measurement of the (2.172±0.017[stat]±0.060[sys])×1021yr half. The collection of both light and charge signals and the reconstruction of event positions for both single and multi-cluster events allow background discrimination on top of the already low environmental background regime, and the possibility of studying events with extended topologies. A 5-tonne next generation liquid xenon experiment, nEXO, based on teh EXO-200 concept while implementing some notable innovations, is currently being designed. It promises to improve the sensitivity to improve the sensitivity to 0νββ of 136Xe by ~2 orders of magnitude and fully access the inverted hierarchy neutrino mass scale. This talk will discuss the detector performance and recent results from EXO-200 and present the nEXO experiment.