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 project is the Majorana Demonstrator and its follow-on LEGEND, which are arrays of HPGe detectors that we are using to search for the neutrinoless double-beta decay of 76Ge, which would demonstrate that the neutrino and the antineutrino are in fact the same particle. This novel possibility for the nature of the neutrino pointed out by Ettore Majorana in 1937 is a generic feature 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!). The Majorana project also has 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 recently made the first observation of coherent elastic neutrino-nucleus scattering (CEνNS). I'm investigating the possibility of fielding 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 is thought to account for a significant portion of the Earth's heat. 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

C. E. Aalseth et al., "Search for Zero-Neutrino Double Beta Decay in 76Ge with the Majorana Demonstrator," https://arxiv.org/abs/1710.11608 (2017).

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).

N. Abgrall et al., "New limits on bosonic dark matter, solar axions, Pauli Exclusion Principle violation, and electron decay from the low-energy spectrum of the Majorana Demonstrator," Phys. Rev. Lett. 118, 161801 (2017).

N. Abgrall et al., "Muon Flux Measurements at the Davis Campus of the Sanford Underground Research Facility with the Majorana Demonstrator Veto System," Astropart. Phys. 93, 70 (2016).

A. Gando et al., "Search for Majorana Neutrinos near the Inverted Mass Hierarchy region with KamLAND-Zen," Editor's Suggestion, Phys. Rev. Lett. 117, 082503; Publisher's Note: Phys Rev. Lett. 117, 109903 (2016).

N. Abgrall et al., "The Majorana Demonstrator Radioassay Program," Nucl. Inst. Meth. Phys. Res. A 828, 22 (2016).

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).

A. Gando et al., "Limit on Neutrinoless ββ Decay of 136Xe from the First Phase of KamLAND-Zen and Comparison with the Positive Claim in 76Ge," Phys. Rev. Lett. 110, 062502 (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).

Click here for a more up-to-date and extensive list of my publications and preprints using the SAO/NASA ADS

Selected Talks

"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).

"0νββ Searches with 76Ge," INT Program INT-17-2a on Neutrinoless Double-beta Decay, Seattle, WA (June 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).

"Testing the Majorana Nature of the Neutrino with Germanium Detectors," 15th Annual Meeting of the Northwest Section of the American Physical Society, University of Washington, Seattle, WA (May 2014).

"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).

Teaching

Introduction to Quantum Mechanics (PHYS 225): Winter 2017

Optics Laboratory (PHYS 331): Autumn 2016

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

Introductory Mechanics (PHYS 121): Autumn 2015, Autumn 2014, Autumn 2013

Senior Honors Seminar (PHYS 486) / Seminar on Current Problems in Physics (PHYS 495): Winter 2013

Biography

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. 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 faculty in 2012.