Current Research

My research interests lie in investigating the properties of fundamental particles and fields, and in performing searches for beyond-the-Standard-Model physics. Currently my efforts are focused on investigating the mass, mixing, nature, and interactions of the neutrino. My main projects are the Majorana Demonstrator and its follow-on LEGEND, which are arrays of HPGe detectors that we are using to search for a "Little Bang" -- the creation of matter without the balancing creation of antimatter -- in the form of neutrinoless double-beta decay of 76Ge. This ultra-rare hypothetical nuclear decay requires that the neutrino and the antineutrino are in fact the same particle, a novel possibility pointed out by Ettore Majorana in 1937. Such Majorana neutrinos are a generic prediction of many Grand Unification Theories, as well as models of leptogenesis, a leading explanation for the predominance of matter in the universe (to which we owe our existence!). These HPGe detector arrays also have sensitivity to light-WIMP dark matter, solar axions, axion-like particles, and other exotic physics like Pauli Exclusion Principle violation and electron decay.

I am also involved in the COHERENT Experiment at the Spallation Neutron Source in Oak Ridge, TN, which made the first observation of coherent elastic neutrino-nucleus scattering (CEνNS). I'm involved in the deployment of a large array of NaI(Tl) scintillating crystals to measure both neutral-current and charged-current scattering of neutrinos from Na and I nuclei. In addition to having sensitivity to CEνNS and non-standard interactions of neutrinos with matter, these interactions also test nuclear models with potential impact to neutrinoless double-beta decay matrix element calculations, solar neutrino physics, and other phenomena.

I am also involved in the KamLAND experiment in Japan, a large liquid scintillator detector that measured the oscillation of reactor antineutrinos. It also measured geoneutrinos, the antineutrino emission from primordial radioactivity in the Earth, which accounts for roughly half of the heat emanating from the Earth's interior. I also participate in KamLAND-Zen, a search for the neutrinoless double-beta decay of 136Xe with the KamLAND detector. In the past I also participated in the NCD phase of the SNO experiment.

Selected Publications

I. J. Arnquist et al., "Final Result of the MAJORANA DEMONSTRATOR's Search for Neutrinoless Double-β Decay in 76Ge", [nucl-ex].

J. Detwiler, "Cryogenic mastery aids bid to spot elusive matter creation" (Nature News & Views article), Nature 604, 42-43 (Apr. 2022).

KamLAND-Zen Collaboration, "First Search for the Majorana Nature of Neutrinos in the Inverted Mass Ordering Region with KamLAND-Zen,” arXiv:2203.02139 [hep-ex] (2022).

M. Agostini et al., "Toward the discovery of matter creation with neutrinoless double-beta decay," submitted for publication in Rev. Mod. Phys, arXiv:2202.01787 [hep-ex] (2022).

N. Abgrall et al., "The Large Enriched Germanium Experiment for Neutrinoless ββ Decay: LEGEND-1000 Preconceptual Design Report," arXiv:2107.11462 [physics.ins-det] (2021).

D. Akimov et al., "First Measurement of Coherent Elastic Neutrino-Nucleus Scattering on Argon," Phys. Rev. Lett. 126, 012002 (2020).

S. I. Alvis et al., "A Search for Neutrinoless Double-Beta Decay in 76Ge with 26 kg-yr of Exposure from the MAJORANA DEMONSTRATOR," Phys. Rev. C 100, 025501 (2019).

D. Akimov et al., "Observation of coherent elastic neutrino-nucleus scattering," Science eaao0990 (2017).

M. Agostini, G. Benato, and J. Detwiler, "Discovery probability of next-generation neutrinoless double-β decay experiments," Phys. Rev. D 96, 053001 (2017).

A. Gando et al., "Reactor On-Off Antineutrino Measurement with KamLAND," Phys. Rev. D 88, 033001 (2013).

B. Aharmim et al., "Combined Analysis of All Three Phases of Solar Neutrino Data from the Sudbury Neutrino Observatory," Phys. Rev. C 88, 025501 (2013).

T. Araki et al. "Experimental Investigation of Geologically Produced Antineutrinos with KamLAND," Nature 436, 499 (2005).

T. Araki et al., "Measurement of Neutrino Oscillation with KamLAND: Evidence of Spectral Distortion," Phys. Rev. Lett. 94, 081801 (2005).

K. Eguchi et al., "First Results from KamLAND: Evidence for Reactor Antineutrino Disappearance," Phys. Rev. Lett. 90, 021802 (2003).

J. A. Detwiler et al., "Magnetization of UBe13 to 60T," Phys. Rev. B 61, 402 (2000).

For a more up-to-date and extensive list of my publications and preprints, see the SAO/NASA ADS and INSPIRE databases.

Selected Talks

"How Neutrinos Benefit Us," public speech at Gedatsu Church USA Spring Festival (May 2021).

"Future Neutrinoless Double-Beta Decay Experiments," invited talk at the Neutrino 2020 Virtual Meeting (June-July 2020).

"Searching for Matter Creation," Liberal Arts 2018 Spring Lecture Series, Art Institute of Seattle (April 2018).

"How a 'Jelly Doughnut' May Explain Why the Universe Exists," interview on Sound Effect by Gabriel Spitzer of KNKX (NPR) / 88.5 FM Seattle (November 2017).

"2β or Not 2β: Majorana Neutrinos, Grand Unification, and the Existence of the Universe," Physics Department Colloquium, University of Washington, Seattle, WA (November 2016).

"Is the Neutrino its Own Antiparticle?" Occidental College 125th Anniversary Distinguished Alumni Speaker Series, Los Angeles, CA (April 2013).

"2012 (John Cusack Vs. the Neutrino)," public lecture on neutrino physics at the Seattle Apocalypse Film Festival, Seattle, WA (December 2012).


Introductory Mechanics (PHYS 121): Autumn 2020, Spring 2020, Spring 2019, Spring 2018, Autumn 2015, Autumn 2014, Autumn 2013

Introduction to Quantum Mechanics (PHYS 225): Autumn 2019, Winter 2019, Winter 2018, Winter 2017

Electromangetism I (PHYS 321): Autumn 2021

Electromangetism II(PHYS 322): Winter 2022

Optics Laboratory (PHYS 331): Autumn 2018, Autumn 2017, Autumn 2016

Modern Physics Laboratory: Atomic Physics (PHYS 432): Spring 2016, Spring 2015, Spring 2014, Spring 2013

Senior Honors Seminar (PHYS 486) / Seminar on Current Problems in Physics (PHYS 494-496): Spring 2022, Autumn 2020, Winter 2013


I grew up in Seattle but did my undergraduate studies at Occidental College where I worked on high-magnetic field condensed matter physics with George Schmiedeshoff, and with Alex Lacerda, then at the National High Magnetic Field Laboratory at Los Alamos National Laboratory. I received my Ph.D. from Stanford University in 2005 working with Giorgio Gratta on the KamLAND experiment, focusing on reactor antineutrino oscillation. My thesis, Measurement of Neutrino Oscillation with KamLAND represented the first observation of spectral distortion in a reactor antineutrino spectrum. KamLAND was one of the experiments awarded the 2016 Breakthrough Prize in Fundamental Physics for the fundamental discovery and exploration of neutrino oscillation.

I did my postdoctoral work at CENPA with John Wilkerson, where I became involved in the Majorana neutrinoless double-beta decay experiment as well as the NCD phase of the SNO solar neutrino oscillation experiment (SNO was also awarded a 2016 Breakthrough Prize in Fundamental Physcis, and the spokesperson, Art MacDonald, received the 2015 Nobel Prize in Physics). I continued this work on Majorana, SNO, and KamLAND as a Seaborg Fellow and then as a Project Scientist at Lawrence Berkeley National Laboratory working with Kevin Lesko, Alan Poon, and Stuart Freedman from 2007 to 2012. I joined the University of Washington Department of Physics faculty in 2012. I'm currently a Co-Spokesperson of Majorana, and a Steering Committee Member and Analysis Co-Coordinator on LEGEND. I'm also on the COHERENT and KamLAND/KamLAND-Zen experiments.

I'm a member of the APS DNP, DPF, and DAP divisions, and the Northwest section. I became an APS Fellow in 2020. I've been affiliated with the Kavli Institute for the Physics and Mathematics of the Universe (U. Tokyo) since 2014. I'm also a member of the Phi Beta Kappa and Sigma Pi Sigma honor societies.