From Caltech and From UC Santa Barbara : “Radioactive Molecules May Help Solve Mystery of Missing Antimatter”

Caltech Logo

From Caltech


UC Santa Barbara Name bloc
From UC Santa Barbara

March 26, 2021
Whitney Clavin
(626) 395‑1944

An artistic representation of the structure of the radium monomethoxide ion, or RaOCH3+, used in the new study. The asymmetrical, or pear-shaped, radium nucleus is highlighted at the top.

Stars, galaxies, and everything in the universe, including our own bodies, are comprised of so-called regular matter. Regular matter includes atoms and molecules, which are made up of tiny particles, such as electrons, protons, and neutrons. These particles dominate our universe, vastly outnumbering their lesser-known counterparts: antimatter particles. First experimentally discovered in 1932 by the late Nobel laureate and longtime Caltech professor Carl Anderson (BS ’27, PhD ’30), antimatter particles have the opposite charges to their matter counterparts.

Carl Anderson with the magnet cloud chamber with which he discovered the positive electron, or positron. For this work he won the Nobel Prize in physics in 1936. Credit: Caltech Archives.

The antimatter particle to the negatively charged electron, for example, is the positively charged positron.

How did matter come to overshadow antimatter? Scientists believe that something happened early in the history of our cosmos to tip the balance of particles to matter, causing antimatter to largely disappear. How this occurred is still a mystery.

In a new study in the journal Physical Review Letters, Nick Hutzler (BS ’07), assistant professor of physics at Caltech, and his graduate student Phelan Yu, propose a new tabletop-based tool to search for answers to the antimatter riddle. Like other physicists studying the problem, the researchers’ main idea is to look for asymmetries in how regular matter interacts with electromagnetic fields. This is related to a type of symmetry commonly seen in particles called charge parity, or CP. Any deviations from the expected CP symmetry might explain how matter ultimately edged out antimatter in our universe.

Hutzler and his colleagues theoretically worked out a new way to probe these symmetry violations using a radioactive molecule called a radium monomethoxide ion, or RaOCH3+. Their partners at UC Santa Barbara(US), led by Andrew Jayich, then created these molecules for the first time and published the results in a companion article in Physical Review Letters.

The joint studies demonstrate that radioactive molecules have the potential to be even more sensitive probes of fundamental particle symmetries than the non-radioactive atoms commonly used today.

“The state-of-the-art method for this type of study uses atoms,” explains Hutzler. “But molecules can be even better probes because they have baked-in asymmetry. They are lumpy and lopsided to begin with. The radium nucleus is even lumpier since it has a very uneven charge distribution, and this also helps. The result is a 100,000 to 1,000,000 larger amplification of symmetry violations, if any are present, compared to what has been state of the art.”

To look for symmetry violations in particles, researchers generally observe how particles behave in electric fields. They search for abnormal behaviors that break the known symmetry rules; for instance, physicists have predicted that symmetry violations might cause an electron to precess, or wobble around like a spinning top, in an electric field. Molecules have electromagnetic fields inside them, due to their asymmetrical nature, so they make ideal targets for this kind of work.

Hutzler says he had thought about using radium-based molecules for this purpose before, even calling himself a “radium fanboy,” but explained that the isotope they need is extremely radioactive with a half-life of two weeks (half of a lump of radium will decay into other nuclei in just two weeks).

“This radium isotope is very radioactive and very scarce, which makes working with it difficult,” explains Hutzler. “But the unique properties of the RaOCH3+ molecule overcome many of these challenges, and, when combined with the experimental technique demonstrated at UC Santa Barbara, will enable modern, quantum, highly sensitive methods to search for these symmetry violations.”

The new tabletop method is complementary to other techniques that search for clues to the antimatter mystery, including related experiments performed in the Hutzler lab as well as the neutron Electric Dipole Moment, or nEDM experiment, which is being built in part at Caltech by Brad Filippone, the Francis L. Moseley Professor of Physics, and his team. In fact, Hutzler worked with Filippone on this experiment as an undergraduate at Caltech. The nEDM experiment, which will ultimately take place at the Oak Ridge National Laboratory in about five years, will look for CP symmetry violations specifically in neutrons.

“This new approach is not as clean and direct as nEDM, but by using a whole molecule, we have the advantage of being able to sense symmetry violations in a range of particles,” says Hutzler.

The radioactive-molecule approach may take years more to fully develop but Hutzler says that he has been enjoying focusing on the theoretical aspect of the work.

“We’ve been starting to dabble more in theory partly due to the pandemic and having more time at home,” he says. “We probably would not have done this theory work otherwise.”

See the full article here .

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UC Santa Barbara Seal

The University of California, Santa Barbara (US) is a public land-grant research university in Santa Barbara, California, and one of the ten campuses of the University of California(US) system. Tracing its roots back to 1891 as an independent teachers’ college, UCSB joined the University of California system in 1944, and is the third-oldest undergraduate campus in the system.

The university is a comprehensive doctoral university and is organized into five colleges and schools offering 87 undergraduate degrees and 55 graduate degrees. It is classified among “R1: Doctoral Universities – Very high research activity”. According to the National Science Foundation(US), UC Santa Barbara spent $235 million on research and development in fiscal year 2018, ranking it 100th in the nation. In his 2001 book The Public Ivies: America’s Flagship Public Universities, author Howard Greene labeled UCSB a “Public Ivy”.

UC Santa Barbara is a research university with 10 national research centers, including the Kavli Institute for Theoretical Physics (US) and the Center for Control, Dynamical-Systems and Computation. Current UCSB faculty includes six Nobel Prize laureates; one Fields Medalist; 39 members of the National Academy of Sciences; 27 members of the National Academy of Engineering; and 34 members of the American Academy of Arts and Sciences. UCSB was the No. 3 host on the ARPANET and was elected to the Association of American Universities in 1995. The faculty also includes two Academy and Emmy Award winners and recipients of a Millennium Technology Prize; an IEEE Medal of Honor; a National Medal of Technology and Innovation; and a Breakthrough Prize in Fundamental Physics.

The UC Santa Barbara Gauchos compete in the Big West Conference of the NCAA Division I. The Gauchos have won NCAA national championships in men’s soccer and men’s water polo.


UCSB traces its origins back to the Anna Blake School, which was founded in 1891, and offered training in home economics and industrial arts. The Anna Blake School was taken over by the state in 1909 and became the Santa Barbara State Normal School which then became the Santa Barbara State College in 1921.

In 1944, intense lobbying by an interest group in the City of Santa Barbara led by Thomas Storke and Pearl Chase persuaded the State Legislature, Gov. Earl Warren, and the Regents of the University of California to move the State College over to the more research-oriented University of California system. The State College system sued to stop the takeover but the governor did not support the suit. A state constitutional amendment was passed in 1946 to stop subsequent conversions of State Colleges to University of California campuses.

From 1944 to 1958, the school was known as Santa Barbara College of the University of California, before taking on its current name. When the vacated Marine Corps training station in Goleta was purchased for the rapidly growing college Santa Barbara City College moved into the vacated State College buildings.

Originally the regents envisioned a small several thousand–student liberal arts college a so-called “Williams College (US) of the West”, at Santa Barbara. Chronologically, UCSB is the third general-education campus of the University of California, after UC Berkeley (US) and UCLA (US) (the only other state campus to have been acquired by the UC system). The original campus the regents acquired in Santa Barbara was located on only 100 acres (40 ha) of largely unusable land on a seaside mesa. The availability of a 400-acre (160 ha) portion of the land used as Marine Corps Air Station Santa Barbara until 1946 on another seaside mesa in Goleta, which the regents could acquire for free from the federal government, led to that site becoming the Santa Barbara campus in 1949.

Originally only 3000–3500 students were anticipated but the post-WWII baby boom led to the designation of general campus in 1958 along with a name change from “Santa Barbara College” to “University of California, Santa Barbara,” and the discontinuation of the industrial arts program for which the state college was famous. A chancellor- Samuel B. Gould- was appointed in 1959.

In 1959 UCSB professor Douwe Stuurman hosted the English writer Aldous Huxley as the university’s first visiting professor. Huxley delivered a lectures series called The Human Situation.

In the late ’60s and early ’70s UCSB became nationally known as a hotbed of anti–Vietnam War activity. A bombing at the school’s faculty club in 1969 killed the caretaker Dover Sharp. In the spring of 1970 multiple occasions of arson occurred including a burning of the Bank of America branch building in the student community of Isla Vista during which time one male student Kevin Moran was shot and killed by police. UCSB’s anti-Vietnam activity impelled then-Gov. Ronald Reagan to impose a curfew and order the National Guard to enforce it. Armed guardsmen were a common sight on campus and in Isla Vista during this time.

In 1995 UCSB was elected to the Association of American Universities– an organization of leading research universities with a membership consisting of 59 universities in the United States (both public and private) and two universities in Canada.

On May 23, 2014 a killing spree occurred in Isla Vista, California, a community in close proximity to the campus. All six people killed during the rampage were students at UCSB. The murderer was a former Santa Barbara City College student who lived in Isla Vista.

Research activity

According to the National Science Foundation (US), UC Santa Barbara spent $236.5 million on research and development in fiscal 2013, ranking it 87th in the nation.

From 2005 to 2009 UCSB was ranked fourth in terms of relative citation impact in the U.S. (behind Massachusetts Institute of Technology (US), California Institute of Technology(US), and Princeton University (US)) according to Thomson Reuters.

UCSB hosts 12 National Research Centers, including the Kavli Institute for Theoretical Physics, the National Center for Ecological Analysis and Synthesis, the Southern California Earthquake Center, the UCSB Center for Spatial Studies, an affiliate of the National Center for Geographic Information and Analysis, and the California Nanosystems Institute. Eight of these centers are supported by the National Science Foundation. UCSB is also home to Microsoft Station Q, a research group working on topological quantum computing where American mathematician and Fields Medalist Michael Freedman is the director.

Research impact rankings

The Times Higher Education World University Rankings ranked UCSB 48th worldwide for 2016–17, while the Academic Ranking of World Universities (ARWU) in 2016 ranked UCSB 42nd in the world; 28th in the nation; and in 2015 tied for 17th worldwide in engineering.

In the United States National Research Council rankings of graduate programs, 10 UCSB departments were ranked in the top ten in the country: Materials; Chemical Engineering; Computer Science; Electrical and Computer Engineering; Mechanical Engineering; Physics; Marine Science Institute; Geography; History; and Theater and Dance. Among U.S. university Materials Science and Engineering programs, UCSB was ranked first in each measure of a study by the National Research Council of the NAS.

The Centre for Science and Technologies Studies at Leiden University [Universiteit Leiden](NL) ranked UCSB as the seventh-best research university in the world based on mean normalized citation score, and as the second best in the world based on the proportion of the publications to the top 10% most frequently cited.

The Global Research Report: United States published by Thomson Reuters in November 2010 rated UCSB’s research fourth nationally in citation impact.

Among U.S. university economics programs, in 2010 UCSB was ranked sixth for experimental economics; third for environmental economics; and 12th for cognitive and behavioral economics by RePEc.

Washington Monthly named UCSB as the 20th best national university in 2020 based on its contribution to the public good as measured by social mobility, research, and promoting public service.

Caltech campus

The California Institute of Technology(US) is a private research university in Pasadena, California. The university is known for its strength in science and engineering, and is one among a small group of institutes of technology in the United States which is primarily devoted to the instruction of pure and applied sciences.

Caltech was founded as a preparatory and vocational school by Amos G. Throop in 1891 and began attracting influential scientists such as George Ellery Hale, Arthur Amos Noyes, and Robert Andrews Millikan in the early 20th century. The vocational and preparatory schools were disbanded and spun off in 1910 and the college assumed its present name in 1920. In 1934, Caltech was elected to the Association of American Universities, and the antecedents of National Aeronautics and Space Administration (US)’s Jet Propulsion Laboratory, which Caltech continues to manage and operate, were established between 1936 and 1943 under Theodore von Kármán.

Caltech has six academic divisions with strong emphasis on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. First-year students are required to live on campus, and 95% of undergraduates remain in the on-campus House System at Caltech. Although Caltech has a strong tradition of practical jokes and pranks, student life is governed by an honor code which allows faculty to assign take-home examinations. The Caltech Beavers compete in 13 intercollegiate sports in the NCAA Division III’s Southern California Intercollegiate Athletic Conference (SCIAC).

As of October 2020, there are 76 Nobel laureates who have been affiliated with Caltech, including 40 alumni and faculty members (41 prizes, with chemist Linus Pauling being the only individual in history to win two unshared prizes). In addition, 4 Fields Medalists and 6 Turing Award winners have been affiliated with Caltech. There are 8 Crafoord Laureates and 56 non-emeritus faculty members (as well as many emeritus faculty members) who have been elected to one of the United States National Academies. Four Chief Scientists of the U.S. Air Force and 71 have won the United States National Medal of Science or Technology. Numerous faculty members are associated with the Howard Hughes Medical Institute(US) as well as National Aeronautics and Space Administration(US). According to a 2015 Pomona College(US) study, Caltech ranked number one in the U.S. for the percentage of its graduates who go on to earn a PhD.


Caltech is classified among “R1: Doctoral Universities – Very High Research Activity”. Caltech was elected to the Association of American Universities in 1934 and remains a research university with “very high” research activity, primarily in STEM fields. The largest federal agencies contributing to research are National Aeronautics and Space Administration(US); National Science Foundation(US); Department of Health and Human Services(US); Department of Defense(US), and Department of Energy(US).

In 2005, Caltech had 739,000 square feet (68,700 m^2) dedicated to research: 330,000 square feet (30,700 m^2) to physical sciences, 163,000 square feet (15,100 m^2) to engineering, and 160,000 square feet (14,900 m^2) to biological sciences.

In addition to managing JPL, Caltech also operates the Caltech Palomar Observatory(US); the Owens Valley Radio Observatory(US);the Caltech Submillimeter Observatory(US); the W. M. Keck Observatory at the Mauna Kea Observatory(US); the Laser Interferometer Gravitational-Wave Observatory at Livingston, Louisiana and Richland, Washington; and Kerckhoff Marine Laboratory(US) in Corona del Mar, California. The Institute launched the Kavli Nanoscience Institute at Caltech in 2006; the Keck Institute for Space Studies in 2008; and is also the current home for the Einstein Papers Project. The Spitzer Science Center(US), part of the Infrared Processing and Analysis Center(US) located on the Caltech campus, is the data analysis and community support center for NASA’s Spitzer Infrared Space Telescope [no longer in service].

Caltech partnered with University of California at Los Angeles(US) to establish a Joint Center for Translational Medicine (UCLA-Caltech JCTM), which conducts experimental research into clinical applications, including the diagnosis and treatment of diseases such as cancer.

Caltech operates several Total Carbon Column Observing Network(US) stations as part of an international collaborative effort of measuring greenhouse gases globally. One station is on campus.