Professor Chupp and his group pursue a program that uses precision measurement techniques and symmetry principles in particle physics investigations and applies the technology developed for those investigations to a variety of endeavors. The primary current efforts include measurement of muon magnetic-moment anomaly (g-2) at Fermilab and atomic and neutron electric-dipole-moment measurements at Los Alamos National Lab.

Over recent decades experiment and theory have established the Standard Model of elementary particle interactions and developed a framework for precise calculations. In spite of this success, strong evidence that the Standard Model is incomplete is provided by three specific shortcomings: 1) we do not understand the origin of matter, that is how the early universe evolved to provide more matter than antimatter for planets, stars and galaxies to exist as observed today; 2) we do not know what constitutes the dark matter that comprises most of the mass of the observable universe; 3) we have not specified the quantum mechanics of neutrinos, the elusive elementary particles that accompany radioactive decay. It is clear that a New Standard Model must emerge and that it must be based on experiment. Chupplab research challenges precise Standard Model predictions and can provide solid signals of new physics by measuring the magnetic signature (magnetic-moment anomaly) of the muon, an exotic elementary particle that is produced in abundance at the Fermi National Accelerator Laboratory, and exquisitely measuring the shape of the neutron and the isotope ¹²⁹Xe manifest in an electric-dipole moment (EDM). This work addresses the deepest questions that we can ask: what is matter made of, how did it come to be and how does it interact at the same time addressing the technical demands of the experiments by pushing the limits of magnetic field measurement. Many potential additional applications of these techniques may be extended into biology, neuroscience and medicine, and as quantum sensors.

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We are part of the Fermilab muon g-2 collaboration and recently announced the results of the Run 1 and Run 2-3. Together with the previous results from Brookhaven, measured g-2 of the muon differs from the recent Standard Model Calculation by 2.5 parts-per-million (ppm), which is about 5 times the estimated combined uncertainty of experiment and a recently compiled Standard-Model calculation. This is currently the strongest laboratory signal for new physics. The Chupp lab has been focused on the absolute and accurate measurement of the magnetic field that connects the muon spin-precession frequency to the magnetic-moment anomaly a_µ= (g-2)/2. The challenge of precision absolute magnetometry has pushed the development of new techniques based on ³He. Combined with measurement of the magnetic moment of the ³He nucleus, this promises to establish a new standard and a new set of devices for measuring magnetic fields.

Time reversal invariance violation is manifest in the EDMs induced in the neutron and atoms by elementary particle interactions. The Standard Model provides for EDMs due to the weak and strong interaction, but the weak interaction contribution is so small that the current experiments probe the strong interaction (the parameter q_QCD)and new physics that may hold the key to the origin of matter. Efforts to exploit the world’s strongest UCN sources at Los Alamos and ILL in Grenoble France are driving our work to push the neutron EDM sensitivity an order of magnitude and more. The Los Alamos nEDM experiment (Tim Chupp and Takeyasu Ito spokespersons) will improve the sensitivity to the neutron EDM by a factor of about 10. The HeXe collaboration improved improved our earlier work to measure the ¹²⁹Xe EDM with ³He co-magnetometry using SQUIDs and the world’s best magnetically shielded environments in Munich and Berlin, Germany by a factor of five. This effort continues using components of the Los Alamos nEDM experiment and SQUID magnetometry.

Review on EDMs with Peter Fierlinger, Michael Ramsey-Musolf, and Jaideep Singh

Review Paper on Medical Imaging with Laser Polarized Noble Gases

Paper on Beyond-Standard-Model Physics experiments at low energy

Faculty/Postdocs

Tim Chupp, Richard Raymond

Felicity B. Hills

Graduate Students

Eva Krageloh – muon g-2 and EDM

Henry Sottrel – ¹²⁹Xe EDM

David Aguillard – ³He magnetometry and muon g-2

Current Undergrads (2024-5)

Eden Anderson, Andrew Andrade, Ian Rhudy, Jamison Starr

Recent PhDs

Felicity B. Hills: Characterization of Magnetic Fields for the Los Alamos National Laboratory nEDM Experiment

Chelsea Hendrus: A polarimetry measurement for the Nab experiment

Alec-Tewsley-Booth: muon g-2 magnetic field analysis

Natasha Sachdeva: HeXe EDM

Midhat Farooq: ³He magnetometry and muon g-2

Skyler Degenkolb: Optical Magnetometry Using Multiphoton Transitions

Matt Bales: Precision Measurment of Radiative Neutron Decay

Behzad Ebrahimi (BME): Cerebral Blood Flow Measurement Using MRI: Mathematical Regularization and Phantom Evaluation

Rob Cooper: The Radiative Decay Mode of the Free Neutron

Eric Tardiff: Towards a Measurement of the Electric Dipole Moment of ²²³Rn

Monisha Sharma: Precision Neutron Polarimetry and npdgamma

Matt Rosen, Mark Rosenberry, Shenq-Rong Huang, Todd Smith, Rohan Hoare, Eduardo Oteiza, Jonathan Richardson, Mark Wagshull, Alan Thompson, Kevin Coulter

2024: Clockwise from upper left: Eden, Harriet, Eva, Tim, Felicity, Aidan, Henry, Richard, Jamison, Andrew Missing: David, Ian, "little Tim"

ChuppLab

chupp@umich.edu

Natasha

Midhat

Chelsea

Eva

Veronica

Jonathan

Scott

Joe

Richard

Tim

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