My research time is divided between the MUon Scattering Experiment (MUSE ) at Paul Scherrer Institute (PSI) in Switzerland, and the A2 Collaboration, at the MAMI accelerator of the Institut für Kernphysik at Johannes Gutenberg University Mainz in Germany.
The MUSE experiment seeks to measure the reaction cross sections of elastic scattering of electrons and muons simultaneously with the same detector system. To do this we will use the mixed pion / muon / electron beam in the piM1 experimental area at PSI. As this is a very non-traditional scattering experiment, with a mixed, low-flux beam, we have to tag and track each beam particle both into and out of the liquid hydrogen target. By so doing, we aim to provide electron and muon cross sections of comparable accuracy to the current electron measurements, and thereby learn some vital information in the quest to solve the Proton Radius Puzzle, a very challenging "hot topic" which has been covered extensively in scientific journals and popular media such as:
- The original Nature article by Pohl et al. which caused the Puzzle.
- A more recent Nature editorial when additional results from the CREMA collaboration were released.
- Scientific American covered the issue, mentioning MUSE.
- New Scientist featured it.
- The Huffington Post also reported on it.
- Even Wikipedia has something to say about the Proton Radius Puzzle!
- For a comprehensive review of the Proton Radius Puzzle see the review by Pohl et al., and a more recent review by Gao and Vanderhaeghen.
- A recent MUSE review.
MUSE has passed scientific review at PSI, was fully funded for construction by an NSF MidScale award, and is now taking engineering data. MUSE plans to take twelve months of production data between 2022 and 2025. For more information see the MUSE homepage, and the MUSE TDR.
At MAMI, as part of the A2 Collaboration, I research the structure and behavior of the nucleons (protons and neutrons) and other nuclei.
The main focus of my MAMI research, at present, is Compton Scattering on the proton and neutron. We have taken data on three different asymmetries in a series of polarized Compton Scattering measurements on the proton, using a circularly polarized photon beam with a transverse polarized target, and a longitudinally polarized target, and a linearly polarized photon beam with an unpolarized liquid hydrogen target. These are the world's first doubly polarized photon asymmetries to be measured in Compton Scattering and we have taken the first polarized data below pion production threshold. A review of recent progress can be found here. The first publication on doubly polarized Compton Scattering, with a world-first experimental extraction of spin polarizabilities, has been published in PRL.
My research and outreach activities have been funded by several grants from the National Science Foundation (NSF), under award numbers PHY-2310026, PHY-2012940, PHY-1714833, PHY-1622510, PHY-1614850, and OISE-1358175.
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