[Marxism] Ann Nelson, Expert on Particle Physics, Is Dead at 61

Louis Proyect lnp3 at panix.com
Wed Aug 28 09:11:25 MDT 2019


("While at the University of Washington, Dr. Nelson became well known 
for championing diversity and social justice in the sciences, and 
particularly for mentoring students from nontraditional backgrounds. As 
part of her efforts to reach more diverse students, she had been giving 
lectures in the Palestinian territories.")

NY Times, Aug. 28, 2019
Ann Nelson, Expert on Particle Physics, Is Dead at 61
By Dylan Loeb McClain

Ann Nelson, a theoretical physicist who helped plug holes and solve 
contradictions in the Standard Model, the template that forms the 
backbone of our understanding of fundamental particles and the universe, 
died on Aug. 4 in the Alpine Lakes Wilderness in Washington State. She 
was 61.

She died in a hiking accident, said her husband, David Kaplan, who is 
also a physicist. He said the two of them were trekking with friends 
when Dr. Nelson slipped and fell into a gully.

Dr. Nelson stood out in the world of physics not only because she was a 
woman, but also because of her brilliance.

Howard Georgi, a Harvard professor who was Dr. Nelson’s doctoral adviser 
and is considered one of the leading theoreticians in particle physics, 
wrote on a eulogy page on the website of the magazine Physics Today: “I 
have had many fabulous students who are better than I am at many things. 
Ann was the only student I ever had who was better than I am at what I 
do best, and I learned more from her than she learned from me.”

In 2018 Dr. Nelson was jointly awarded, with Michael Dine of the 
University of California, Santa Cruz, the J.J. Sakurai Prize, considered 
the highest prize in particle physics outside  the Nobel.

She also received a Guggenheim Fellowship in 2004 and was elected to the 
American Academy of Arts and Sciences in 2011.

Particle physics focuses on the basic building blocks of everything in 
the universe. The fundamental particles that have so far been identified 
have been given esoteric names like quarks, leptons, muons and taus. 
Electrons, the negatively charged particles that circle the nuclei of 
atoms, are leptons, while protons and neutrons, which form the nuclei of 
atoms and therefore make up most of the visible mass in the universe, 
are each composed of three quarks.

Together, all those particles form the Standard Model of particle 
physics, the creation of which is one of the signature accomplishments 
of physicists in the 20th century and underlies the field of quantum 
physics.

Though the Standard Model has proved to be consistent in predicting 
experimental results, it falls short of providing a complete explanation 
of interactions among particles, and of how the universe works. Some of 
those shortcomings were what Dr. Nelson addressed in her work.

One problem she tackled was explaining why there seems to be so much 
more matter than antimatter in the universe, a violation of a basic 
principle in physics called symmetry. According to physics computations 
and theories, they should exist in equal amounts.

(It is a good thing that they do not, as matter and antimatter cancel 
each other out when they are combined, which means that if they did 
exist in equal amounts you wouldn’t be reading this article and none of 
what we know as the universe would exist.)

To account for the discrepancy, Dr. Nelson and others came up with a 
rigorous mathematical and theoretical model that allowed for a violation 
of the symmetry rule during the time that the universe was expanding and 
matter and antimatter were being created.

She also worked on theories to extend the Standard Model to include 
super particles that would be a combination of fermions (quarks and 
leptons) and bosons (particles that, like photons, carry forces). 
Physicists have been anticipating their discovery for decades and 
working on experiments to find them.

Ann Nelson was born in Baton Rouge, La., on April 29, 1958, the oldest 
of three daughters of Howard and Dorothy Ann Nelson. Her father was a 
vice president at Kaiser Aluminum; her mother was a docent at the M. H. 
de Young Memorial Museum in San Francisco after the family moved to the 
Bay Area when Ann was young.

Ann attended Acalanes High School in Lafayette, Calif., where she was 
the valedictorian, and then Stanford University. It was there, during a 
freshman year advanced physics class, that Ann met David Kaplan, a 
fellow student.

She worked for one summer at the European Organization for Nuclear 
Research in Geneva, known as CERN, the world’s largest nuclear 
accelerator, before graduating from Stanford in 1980. She continued on 
to Harvard, earning her Ph.D. in 1984. Before receiving her doctorate, 
she published her first paper, without any co-authors — rare even for 
established theorists.

After teaching at other universities, she and Dr. Kaplan, who were 
married in 1987, ended up at the University of Washington in 1994. That 
was where she was working when she died.

Her accident was unusual, Dr. Kaplan said, as they hiked regularly and 
had taken on far more dangerous passages than the one on which she fell. 
She was a moderator of the Washington Hikers and Climbers Facebook page, 
which has nearly 120,000 members. On Sunday, the page’s profile 
photograph was still of Dr. Nelson hiking in 2018 in the Cascades in 
Washington State.

In addition to Dr. Kaplan, with whom she lived in Seattle, Dr. Nelson is 
survived by their daughter, Sierra Kaplan-Nelson; their son, Gabriel 
Kaplan-Nelson; her parents; and her sisters, Laura Segala and Caroline Kris.

While at the University of Washington, Dr. Nelson became well known for 
championing diversity and social justice in the sciences, and 
particularly for mentoring students from nontraditional backgrounds. As 
part of her efforts to reach more diverse students, she had been giving 
lectures in the Palestinian territories.

In particle physics, it is often difficult to create the models to 
explain how particles interact, partly because the results can be 
strange, even unsettling. Dr. Nelson knew and accepted this.

“Ann told me,” Chanda Prescod-Weinstein, a cosmologist based at the 
University of New Hampshire who did postdoctoral work under Dr. Nelson 
at the University of Washington, wrote in Quanta magazine after her 
death, “that to be happy as a model builder in particle physics, I had 
to be O.K. with something like mounting a moose head on a wall and 
putting a purple scarf on it and not worrying about why it was wearing a 
purple scarf.”



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