Raymond W. Hayward

Raymond Webster Hayward was born in Omaha, NebraskaNebraskaNebraska is a state of the United States bordered by South Dakota to the north, Iowa and Missouri to the east, Kansas to the south, and Colorado to the southwest, with its panhandle bordering Wyoming to the west; its capital is Lincoln and its largest city is Omaha. It was admitted to the Union on March 1, 1867, as the 37th state, and its population in the 2020 census (April 1, 2020) was 1,961,504.Open the full entry, on July 28, 1921.⁠[1][2]

In 1943 he received a B.S. from Iowa State College. The Physics Today obituary gives the field as electrical engineering, while the staff profile on the history pages of the National Institute of Standards and Technology (NIST) gives it as physics.⁠[1][3]

During the Second World War he served in the United States Navy and was stationed at the Naval Research Laboratory in Washington, D.C., where his work included putting connectors on cables, drawing up a wiring diagram for a captured Japanese fighter plane and designing antennas.⁠[1]

The NIST staff profile lists him as an electronics engineer at the Naval Research Laboratory in 1943–1945; the short biography in NIST’s “The Fall of Parity” exhibit has him working there as an electronic scientist from 1943 until 1950.⁠[3][2]

He enrolled in graduate studies in physics at the University of California, BerkeleyUniversity of California, BerkeleyThe University of California, Berkeley (UC Berkeley) is a campus of the University of California system; the University of California was founded in 1868 through a merger of two institutions and moved to Berkeley, California, in 1873.Open the full entry, receiving an M.A. in 1948 and a Ph.D. in 1950. His thesis, supervised by A. Carl Helmholz, dealt with the construction of a beta-ray spectrometer and its use in studies of nuclear beta decay.⁠[1]

The NIST staff profile gives the subject of his doctoral thesis as beta- and gamma-ray spectroscopy.⁠[3]

From 1948 to 1950 he was a pre-doctoral fellow of the Atomic Energy Commission.⁠[3]

In 1947 he married the experimental physicist Evans Vaughan, whom he had met at Berkeley.⁠[1][4]

In 1950 he joined the nuclear physics section headed by Ugo Fano at the National Bureau of Standards (later NIST) and began decay-scheme studies. Evans HaywardEvans HaywardEvans Hayward (1922–2020), full name Evans Vaughan Hayward, was a physicist at the United States National Bureau of Standards (now the National Institute of Standards and Technology, NIST) who worked for decades in photonuclear physics. She was the wife of the physicist Raymond W. Hayward.Open the full entry was recruited by the bureau in the same year.⁠[1][3][4]

The Physics Today obituary explains how the appointment came about: around 1950 Emilio Segrè let Evans Hayward know that Fano, at the National Bureau of Standards in Washington, had an opening for Hayward to run an experimental beta-spectrometry program, and as a result both of them obtained positions at the bureau. The NIST staff profile says that he was hired by Ugo Fano.⁠[1][3]

In 1952 he moved to the Radioactivity Section under Wilfrid Mann, where he developed early beta–gamma coincidence techniques for standardizing radionuclides used in nuclear medicine, such as iodine-131.⁠[3][1]

In 1953 he published an article on the design and construction of beta-ray spectrometers in Advances in Electronics.⁠[1]

The NIST staff profile explains that beta–gamma coincidence techniques record simultaneous detections of beta particles and gamma rays. The Physics Today obituary counts those he developed among the first of their kind and calls the 1953 article a “definitive description.”⁠[3][1]

In 1956 Tsung-Dao LeeTsung-Dao LeeTsung-Dao Lee (1926–2024) was a Shanghai-born American physicist who taught for decades at Columbia University. In 1956 he and Chen Ning Yang proposed that parity might not be conserved in weak interactions, for which they shared the 1957 Nobel Prize in Physics; from the 1970s he helped advance high-energy physics and the training of physicists in China.Open the full entry of Columbia UniversityColumbia UniversityColumbia University, formally Columbia University in the City of New York, is a private research university in New York City and a member of the Ivy League. Founded in 1754 by royal charter from King George II as King's College, it is the oldest institution of higher education in New York State and the fifth oldest in the United States. It was renamed Columbia College in 1784 and adopted the university name and moved to Manhattan's Morningside Heights in 1896. It has 17 schools and four affiliated colleges, with 35,978 students enrolled in fall 2025. Legal scholar Jennifer L. Mnookin became president on July 1, 2026.Open the full entry and Chen Ning YangChen Ning YangChen Ning Yang (1922–2025) was a theoretical physicist born in Hefei, Anhui, China, who shared the 1957 Nobel Prize in Physics with Tsung-Dao Lee for their investigation of the parity laws. In 1954 he and Robert L. Mills formulated non-Abelian gauge theory (Yang–Mills theory), and he worked in turn at the Institute for Advanced Study, Stony Brook University and Tsinghua University.Open the full entry of the Institute for Advanced Study proposed that parity might not be conserved in weak interactions and suggested experiments to test the idea, among them a measurement of the directional distribution of beta emission from oriented cobalt-60 nuclei. On the suggestion of Henry Boorse and Mark W. Zemansky, Chien-Shiung Wu of Columbia University contacted Ernest Ambler at the National Bureau of Standards, and the experiment was then arranged in the bureau’s low-temperature laboratory.⁠[5][6]

Ambler and Ralph P. Hudson, chief of the cryogenic physics section, first checked the situation with the bureau’s beta-decay experts, Hayward and Dale D. Hoppes, and then agreed to try. Magdolna Hargittai’s article in Physics World dates a meeting between Chien-Shiung Wu and Ambler in Washington to September 1956, at which the two invited three of his colleagues at the bureau to join them: Hudson, an expert in cryogenics, and the radiation-detection experts Hayward and Hoppes.⁠[7][8]

Hudson’s article for NIST adds that Chen Ning Yang and Tsung-Dao Lee had consulted Chien-Shiung Wu, a beta spectroscopist and their colleague at Columbia University; that Henry Boorse of Columbia and Mark W. Zemansky of the City College of New York, who ran a modest research program in cryophysics at Columbia University, lacked the facilities the experiment required but knew that Ambler had recently moved to the National Bureau of Standards from the cryonuclear physics program at Oxford; and that the bureau’s low-temperature laboratory was chosen because it could work in the millikelvin range and its staff had experience in orienting atomic nuclei. The 2021 article in NIST’s “Taking Measure” blog states that Tsung-Dao Lee had described the ideas to her before the paper was published.⁠[5][9]

The same article relates that when Chien-Shiung Wu looked for a low-temperature laboratory to host the test, those at Oak Ridge National Laboratory and Leiden University were busy with their own work, while the one at the National Bureau of Standards was between major projects. In the question period of a colloquium that Tsung-Dao Lee gave at NIST in 2005 for the experiment’s 50th anniversary, Hudson said that she was at the top of her field and had worked on the Manhattan ProjectManhattan ProjectThe Manhattan Project was the United States program that developed the atomic bomb during the Second World War, managed from 1942 by the Manhattan Engineer District of the Army Corps of Engineers with British and Canadian participation. It built plants and laboratories at Oak Ridge, Tennessee, Hanford, Washington, and Los Alamos, New Mexico, among other sites, carried out the first nuclear test in 1945, and produced the bombs dropped on Hiroshima and Nagasaki, Japan, later that year; after the war its functions passed to the civilian Atomic Energy Commission.Open the full entry, so that her inquiry deserved serious attention; their superior, Ferdinand Brickwedde, approved the work on condition that it cost no money. In his oral history Ambler said “We went for it very hard” and recalled that senior physicists at the bureau considered the experiment a very long shot.⁠[9]

The same article relates that at the 2005 colloquium Tsung-Dao Lee read out Chien-Shiung Wu’s published account of her reaction: she and her husband had booked passage on the Queen Elizabeth to attend a conference in Geneva and then travel to East Asia, but she realized that she had to do the experiment immediately, before others did it first. Hargittai’s article says that in the spring of 1956 Tsung-Dao Lee asked her in her office about the experimental evidence for parity conservation in beta decay, that she proposed a cobalt-60 beta source polarized by demagnetization, and that she recalled it in 1973 as a “golden opportunity for a beta-decay physicist”; that spring she began planning the experiment and cancelled a trip to China, which she had not visited for about 20 years. The experiment required combining two techniques never before used together, and she lacked the equipment and expertise for work near absolute zero.⁠[9][8]

James Schooley’s tribute to Hudson says that Chien-Shiung Wu telephoned Ambler, acquainted him with the Lee–Yang paper, which then existed only as a preprint, and asked whether the National Bureau of Standards would try the experiment. Hargittai’s article has the joint team starting measurements in October 1956; the NIST article speaks of six months of work in 1956 and says that she sent graduate students to the bureau’s headquarters, then in Washington, and travelled there herself periodically. A NIST history volume states that Hudson shared with Ambler the responsibility for the cryogenic aspects of the experiment.⁠[7][8][9][10]

Hayward and Hoppes were both members of the Radioactivity Section of the Atomic and Radiation Physics Division and were responsible for the radiation physics portion of the experiment; Hayward and his student Hoppes helped design and construct the coincidence system used in it.⁠[10][1][11]

In a NIST oral history interview Ambler recalled that Chien-Shiung Wu, Hayward and Hoppes contributed the beta-particle detection and counting side of the experiment, while he and Hudson contributed the low-temperature side.⁠[9]

In quoting Ambler, the NIST article adds in brackets that Hayward was “a theoretical nuclear physicist” and Hoppes “a grad student and later leader of the NIST radioactivity group.”⁠[9]

The cobalt-60 was placed in a thin surface layer of a cerous magnesium nitrate crystal and cooled by adiabatic demagnetization. A thin anthracene scintillation crystal inside the vacuum flask detected the beta particles, the light passing through a 120 cm lucite light pipe to a photomultiplier, and two external sodium iodide gamma counters measured the degree of nuclear polarization. The work-up took about six months, during which outgassing problems led to a redesign of the apparatus from stainless steel to glass.⁠[5]

Hudson’s article gives further details: the anthracene crystal sat about 2 cm above the cobalt-60 source, the pulses were counted on a 10-channel pulse-height analyzer, the adiabatic demagnetization used a field of about 2.3 tesla (23 kilogauss), and the specimen reached about 0.003 K, the figure that NIST’s exhibit page also gives; that page puts the thickness of the surface layer holding the cobalt-60 at 50 µm. The biographical memoir of Chien-Shiung Wu written by Noemie Benczer-Koller for the National Academy of Sciences describes the crystal as “cerium magnesium (cobalt) nitrate,” gives the temperature as 0.01 K and the length of the light pipe as 4 feet.⁠[5][6][11]

The article also sets out the difficulties of the design: the beta source had to be in contact with the cooling medium, a paramagnetic crystal, and yet lie at its surface so that the beta particles could escape; the external field needed for polarization must not warm the crystal; and the strength of the source had to balance sensitivity against local heating. Cerous magnesium nitrate is strongly anisotropic magnetically, which allowed a large cooling field in the plane of the crystal and a small polarizing field perpendicular to it. The crystal sat in an evacuated flask immersed in liquid helium within a jacket of liquid nitrogen, an inductance coil on the inner flask measuring the temperature through the crystal’s magnetic susceptibility, and both gamma counters were set to accept only photopeak pulses.⁠[5]

Beta emission was measured with the polarizing field first in one direction and then in the other. Hudson’s article states that more beta particles were emitted in the direction opposite to the nuclear spin and that the asymmetry was as large as it could be; the NIST article quotes Chien-Shiung Wu calling the results “reproducible and huge.” The National Academy of Sciences memoir says that a large effect had been observed by the end of December 1956.⁠[5][9][11]

On December 27, 1956, the National Bureau of Standards experimenters saw the first signs of the asymmetry. Page 90 of Ambler’s notebook records that day’s experiment; Hudson later added “PARITY NOT CONSERVED!” at the top of the page. NIST’s page says that the first of two successful runs that day began at 12:04 and that the opposite trend was seen once the polarization was reversed.⁠[8][6]

Hargittai’s article says that Chien-Shiung Wu had teaching duties at Columbia University, could not be at the National Bureau of Standards all the time and was absent on December 27; on hearing the news she hurried to Washington, and a few days later she informed Tsung-Dao Lee and Chen Ning Yang at Columbia University. The NIST article adds that she travelled to the bureau and was very hesitant to accept the results. In an e-mail to Hargittai, Dale D. Hoppes wrote that she probably regretted her absence to the last day of her life.⁠[8][9]

Also in 1956 he became an adjunct professor of physics at the University of Maryland, College ParkUniversity of Maryland, College ParkThe University of Maryland, College Park is a university in College Park, Maryland, United States, whose forerunner was the Maryland Agricultural College.Open the full entry. The short biography in NIST’s “The Fall of Parity” exhibit has him as a professor there from 1961 to 1982.⁠[1][3][2]

At about 2 a.m. on January 9, 1957, the team was finally convinced of the result. The paper “Experimental test of parity conservation in beta decay” appeared in the February 15, 1957, issue of the Physical Review (volume 105, pages 1413–1415), with C. S. Wu, E. Ambler, R. W. Hayward, D. D. Hoppes and R. P. Hudson as authors in that order.⁠[9][5]

Once the team was convinced, Hudson took a bottle of wine from a drawer and set it on a table with small paper cups. Tsung-Dao Lee quoted Chien-Shiung Wu’s words: “We finally drank to the overthrow of the law of parity.” Hudson said that the wine was a Chateau Lafite Rothschild of the 1949 vintage.⁠[9][8]

The NIST article says that before publishing the team had to confirm the result under pressure, because researchers at Columbia University were preparing to publish on the same question; theorists had expected very little difference when the direction of the spin was reversed.⁠[9]

Hudson’s article states that Chien-Shiung Wu’s colleagues at Columbia University designed an experiment at the Columbia University cyclotron and within a day or two demonstrated the parity effect in a meson-decay experiment, long before the National Bureau of Standards team could carry out all the check experiments it had planned; the National Academy of Sciences memoir says that Leon Lederman, Richard Garwin and Marcel Weinrich detected the asymmetry in muon decay. Hargittai’s article relates that on January 4, 1957, Tsung-Dao Lee spoke about the bureau’s result at the Columbia University physicists’ regular Chinese lunch; that Leon Lederman telephoned Richard Garwin at home at about 8 p.m. that evening with a test using muons; that the two, using apparatus that Lederman’s graduate student Marcel Weinrich had built for another project, took measurements from the early hours of January 5 until dawn on January 8 and wrote their report that day; and that Tsung-Dao Lee advised against submitting it first, arguing that this would be unfair to the National Bureau of Standards team, which had worked for months.⁠[5][8][11]

Hargittai’s article says that the National Bureau of Standards team’s paper was completed on January 10, 1957; the team and Garwin, Lederman and Weinrich submitted their papers on the same day, both were received by the Physical Review on January 15, and the two appeared back to back in the February 1957 issue; on January 15 the physics department of Columbia University held a press conference announcing the violation of parity, which members of the National Bureau of Standards team attended.⁠[8][9]

The paper lists Chien-Shiung Wu first, with Columbia University as her affiliation, followed by the National Bureau of Standards authors in alphabetical order. Hargittai writes that the order was proposed by the bureau’s team, departing from its usual alphabetical custom: Ambler wrote to her that he had put Chien-Shiung Wu first as a courtesy because she had brought the preprint of the paper by Tsung-Dao Lee and Chen Ning Yang, while the other bureau authors believed it was a courtesy to a woman. She also notes that the two-page report never says that the experiment was carried out at the National Bureau of Standards, an omission she considers misleading.⁠[8]

In the same year the five published a second paper in the Physical Review (volume 106, pages 1361–1363); the experiment used cobalt-58, a positron emitter, showed the opposite effect, the positrons being emitted preferentially along the nuclear spin, and provided additional confirmation of the conjecture of Tsung-Dao Lee and Chen Ning Yang.⁠[5][6]

In 1957 the Department of Commerce presented its Gold Medal (the Award for Exceptional Service) to the National Bureau of Standards team.⁠[5][3]

The 1957 Nobel PrizeNobel PrizeThe Nobel Prize is an international award established under the will of Alfred Nobel, comprising five prizes in physics, chemistry, physiology or medicine, literature and peace, awarded since 1901; its funds are managed by the Nobel Foundation, whose Board is based in Stockholm. The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel, established in 1968, is not a Nobel Prize.Open the full entry in Physics was shared by Tsung-Dao Lee and Chen Ning Yang.⁠[9]

After several follow-up experiments with his colleagues in the low-temperature laboratory he returned to the Radioactivity Section. With students from the University of Maryland and the Catholic University of America he also studied correlations among the nuclear spin, the beta particles and the gamma rays that follow them, as well as other fundamental characteristics of beta decay.⁠[5][1]

He spent the year 1961–1962 in Copenhagen at the Institute for Theoretical Physics (later the Niels Bohr Institute), taking part in discussions of the leading problems in nuclear and particle physics among about 50 distinguished visitors.⁠[1][3]

Evans Hayward was at the same institute that year as a Guggenheim Fellow.⁠[4]

A paper by J. F. Schooley, D. D. Hoppes and A. T. Hirshfeld on the gamma-ray distribution from oriented cerium-141, in the July–August 1962 issue of the Journal of Research of the National Bureau of Standards, lists among its references an article by R. W. Hayward and D. D. Hoppes in the IRE Transactions on Nuclear Science (1958, NS-5, number 3) and a paper by R. W. Hayward, A. T. Hirshfeld, D. D. Hoppes and R. S. Kaeser that was then still to be published.⁠[12]

In 1962 the Franklin Institute awarded its John Price Wetherill Medal to Chien-Shiung Wu and her four collaborators at the National Bureau of Standards for demonstrating that parity is not conserved in weak interactions. The notice in Physics Today places the award ceremony in Philadelphia on October 17.⁠[5][13]

In the Franklin Institute’s register of laureates, the page for Ernest Ambler files the 1962 Wetherill medal under the subject area Chemistry, with the citation “Experimental disproof of the conservation of parity.” The NIST staff profile spells the award “John Price Weatherill Award” and marks it and the Samuel Wesley Stratton Award as joint awards.⁠[14][3]

In 1964 he was promoted to chief of the Nuclear Spectroscopy Section. The Physics Today obituary states that the section was created as a separate unit in the mid-1960s and that he was appointed its chief at that time.⁠[3][1][5]

In the same year the National Bureau of Standards gave the parity team its own highest recognition, the Samuel Wesley Stratton Award.⁠[5][3]

In 1976 the National Bureau of Standards published his monograph The Dynamics of Fields of Higher Spin (NBS Monograph 154), which develops a relativistic theory of higher-spin fields using the variational methods of classical Lagrangian field theory.⁠[15][5][1]

The Physics Today obituary says that for the 20 years after his return from Copenhagen he worked on various areas of theoretical physics, among them the long-standing problem of the dynamics of fields with spin greater than one, and calls the monograph a comprehensive study. Hudson’s article calls it “a monumental treatise” and says that he then turned to the study of gravitation.⁠[1][5]

From the late 1970s he studied the detection of gravitational waves, concentrating on quantum nondemolition measurements and the quantum properties of the macroscopic harmonic oscillator.⁠[1]

The obituary explains that this work concerned how observables of the oscillator can be measured without disturbing later measurements, with the aim of a precision better than the quantum-limit uncertainty, and that he pursued it for the rest of his career.⁠[1]

The Physics Today obituary and Ralph P. Hudson’s article for NIST both date his retirement from the National Bureau of Standards to 1980, the latter adding that he was 59. The short biography in NIST’s “The Fall of Parity” exhibit gives 1986 as the year of retirement, and the list of the NIST Gallery of Distinguished Scientists, Engineers, and Administrators likewise gives the tenure of “Hayward, Raymond” as 1950–1986.⁠[1][5][2][16]

After retiring he continued to study electromagnetism, quantum mechanics, relativity, weak interactions and gravitation.⁠[1]

The NIST staff profile lists his research interests as quantum mechanics, the weak interaction, nuclear beta decay, gravitational waves, spontaneous nuclear transitions and electromagnetism.⁠[3]

In 1982 the National Museum of American History in Washington, D.C., marked the 25th anniversary of the parity experiment with an exhibit entitled “The Fall of Parity”; much of the apparatus shown was reassembled with the help of Hayward and Bruce Dove.⁠[17]

NIST’s online exhibit of the same name went online in July 1997; Hayward, Ralph P. Hudson and Michael Danos gave advice and other help in its preparation.⁠[17]

NIST’s exhibit page states that the 1982 exhibit was the work of Paul Forman, curator for modern physics at the Smithsonian InstitutionSmithsonian InstitutionThe Smithsonian Institution is a museum, education and research institution created by the U.S. Congress in 1846 with the bequest of the English scientist James Smithson. Based in Washington, D.C., it runs museums such as the National Air and Space Museum and the National Museum of Natural History, as well as the National Zoo.Open the full entry’s museum, that the title, the introductory paragraph, the section “Parity: What’s Not Conserved?” and certain other material of the online exhibit are taken from or based on his exhibit, and that its descriptive account of the experiment is largely taken from an article of April 1957 in the NBS Technical News Bulletin (volume 41, number 4); the online exhibit was prepared by the NIST Physics Laboratory (now part of the Physical Measurement Laboratory) as a project of the NIST Museum Committee and designed by W. C. Martin, J. Coursey and R. A. Dragoset. The page also says that the reassembled apparatus is on long-term loan from the National Museum of American History to the NIST Museum in Gaithersburg, MarylandMarylandMaryland is a Middle Atlantic state of the United States, deeply indented by Chesapeake Bay and bordered by Pennsylvania, Delaware, Virginia, the District of Columbia and West Virginia; its capital is Annapolis and its largest city is Baltimore. One of the original 13 states, it ratified the U.S. Constitution on April 28, 1788, as the seventh state to do so, and had a population of 6,177,224 in the 2020 census (April 1, 2020).Open the full entry.⁠[17]

He died at his home in Bethesda, Maryland, on December 24, 2001, following a heart attack.⁠[1]

Physics Today published his obituary in its October 2002 issue (volume 55, number 10, pages 71–72); written by Ralph P. Hudson, Bert Coursey and Sydney Meshkov, it opens by calling him “a nuclear physicist and expert in the physics of beta decay in radionuclides.”⁠[1]

He was a Fellow of the American Physical Society.⁠[3]

The American Physical Society designated the place where the 1956 experiment was done a “historic site.” It was then on the campus of the National Bureau of Standards and by 2011 was the site of the University of the District of Columbia; the commemorative plaque unveiled on November 9, 2011, names C-S Wu, E. Ambler, R.W. Hayward, D.D. Hoppes and R.P. Hudson.⁠[18]

The plaque’s inscription says that the experiment revealed that in certain nuclear processes mirror-image pairs of events occur with different probabilities, a discovery that “revolutionized our understanding of nature’s fundamental laws.” Kate Kirby, executive officer of the American Physical Society, Allen Sessoms, president of the University of the District of Columbia, and Katharine Gebbie, director of NIST’s Physical Measurement Laboratory, took part in the unveiling.⁠[18]

The 2020 list of the NIST Gallery of Distinguished Scientists, Engineers, and Administrators has a line for “Hayward, Raymond,” with “N/A” in the column for the year of induction.⁠[16]

The NIST article carries a photograph of the bureau’s four experimenters with their equipment, from left Hudson, Ambler, Hoppes and Hayward, credited to the NIST Digital Archives. Hargittai’s article sets out, under the heading “Candidates for credit,” the portraits of eleven people: Ambler, Hayward, Chien-Shiung Wu, Hoppes, Hudson, Lederman, Garwin, Tsung-Dao Lee, Chen Ning Yang, Friedman and Telegdi.⁠[9][8]

Hudson’s article says that the result overturned a principle that nuclear physics had accepted for about 30 years, that lifting the restriction of parity conservation resolved the “tau-theta puzzle” in the theory of subatomic particles, and that later theory and experiment led to the unification of the weak and electromagnetic interactions, for which he refers to the Nobel lectures of Weinberg, Salam and Glashow. The NIST article cites the Massachusetts Institute of Technology physicist and historian of science David Kaiser, writing in Science on February 5, 2021, that the discovery set the stage for modern particle theory. Hargittai’s article also relates that Valentine Telegdi and Jerome Friedman began another experiment in the summer of 1956 without knowing of the work at the National Bureau of Standards, were already taking measurements in October, and had their paper received by the journal on January 17, 1957; she judges it most probable that the bureau’s team saw the first genuine signs, on December 27, but needed time to verify them.⁠[5][9][8]

Hudson’s article describes the reaction among physicists: sessions at the American Physical Society meeting in New York in January 1957 were packed, while some scientists exchanged their earlier skepticism about the Lee–Yang proposal for disbelief in the results. When the news broke, Georges M. Temmer of the Carnegie Institution’s Department of Terrestrial Magnetism, a colleague of the bureau’s experimenters, was touring Western Europe; when he informed Wolfgang PauliWolfgang PauliWolfgang Pauli (1900–1958) was a Vienna-born theoretical physicist who received the 1945 Nobel Prize in Physics for the discovery of the exclusion principle, also called the Pauli principle, and who in 1930 proposed the neutral particle later named the neutrino; he was professor of theoretical physics at ETH Zurich from 1928 until his death.Open the full entry that parity was no longer assumed to be conserved, Pauli called it nonsense and said the experiment would have to be repeated.⁠[5]

The same article says that less well-informed parts of the scientific community in the United States and elsewhere were reluctant to credit the staff of the National Bureau of Standards: at a colloquium in Switzerland Temmer corrected an announcement of the “triumph at Columbia” by pointing out that the work had been done at the bureau and was hooted down, and afterwards the experiment was almost always called “the Wu experiment,” with only Chen Ning Yang and Nicholas Kurti trying to correct the record.⁠[5]

Hargittai’s article says that the press conference at Columbia University added emphasis to Chien-Shiung Wu’s role and that the label “Wu experiment” was a convenient shorthand because she had proposed the experiment; Telegdi, Nicholas Kurti and Christine Sutton all questioned the label and stressed the cryogenic work, Ambler and Hudson both having been Kurti’s students at Oxford. A commentary by Kurti and Sutton in Nature in 1997 (volume 385, page 575) called the experiment a collaborative team effort combining nuclear and cryogenic expertise; the Nobel Prize laureate Val Fitch, interviewed by her in 2002, said that all who did the cobalt-60 experiment contributed substantially although “Ms Wu is often given the credit”; and Telegdi, interviewed the same year, held that no experimentalist deserved the prize because the experiment used known techniques and had been suggested by theorists. Her own impression from the surviving participants was that the roles of Chien-Shiung Wu and of Columbia University may have been overemphasized in early coverage.⁠[8]

The NIST article points out that the National Bureau of Standards researchers received neither a Nobel Prize nor a Wolf Prize. Hargittai cites the explanation of Anders Bárány, a former secretary of the Nobel Committee for Physics, that the prize requires work published before the year of the award, so that the three experimental papers, all published early in 1957, could not have qualified in 1957; she adds that the statutes allow at most three laureates and that the number of physicists involved in the experiments would have made any choice difficult.⁠[9][8]

Hudson’s article ends with the later careers of the other experimenters. Chien-Shiung Wu returned to full-time research on beta decay and the training of graduate students at Columbia University, received the National Medal of Science and was elected president of the American Physical Society in 1975, received the Wolf Prize in Physics in 1978, and died in New York in February 1997 at the age of 84. Hudson himself became chief of the Heat Division in 1961, was deputy director, under Karl G. Kessler, of the Center for Absolute Physical Quantities after the reorganization of 1978, resigned in 1980 to become director of publications and editor of Metrologia at the Bureau International des Poids et Mesures in Sèvres, France, retired in 1989 at the age of 65 and then held a three-year temporary post as program director for low-temperature physics at the National Science Foundation. Ambler succeeded him as chief of the Cryogenic Physics Section, was director of the National Bureau of Standards from 1978 to 1988, received the President’s Award for Distinguished Federal Civilian Service and retired from NIST in 1989 at the age of 65. Dale D. Hoppes continued his studies of beta-particle distributions from oriented nuclei in the Nuclear Spectrometry Section, received a Ph.D. from the Catholic University of America in 1961, became Radioactivity Group Leader in 1981 and retired from NIST in 1992 at the age of 64.⁠[5]

His hobbies included mountain climbing, hunting and fly-fishing; he also enjoyed listening to classical music and owned a sizeable collection of recordings. The Haywards regularly entertained physicists from all over the world and were known for the large parties they gave when the American Physical Society met in Washington.⁠[1]

The Physics Today obituary describes him as “courtly, affable” and as having “a wry sense of humor.”⁠[1]

His wife, Evans Vaughan Hayward, was born at Camp Dix, New JerseyNew JerseyNew Jersey is a state in the eastern United States on the Atlantic Ocean, bordered by New York State, Delaware, and Pennsylvania, with the Hudson River forming its northeastern boundary and the Delaware River its western boundary; its capital is Trenton and its largest city is Newark. One of the original 13 colonies, it became the third state to ratify the U.S. Constitution on December 18, 1787, and its population in the 2020 census (April 1, 2020) was 9,288,994.Open the full entry, on February 17, 1922. She received a B.A. in physics from Smith CollegeSmith CollegeSmith College is a liberal arts college for women in Northampton, Massachusetts, United States. Chartered in 1871 under the bequest of Sophia Smith and opened in 1875, it is one of the Seven Sisters schools.Open the full entry in 1942 and did graduate work at the University of California, taking a master’s degree in 1945 (an MS in the Physics Today obituary, an M.A. in the NIST staff profile) and a Ph.D. in 1947; her doctoral research used a cloud chamber to study ionization by high-energy cosmic-ray electrons.⁠[4][19]

From 1947 to 1950 she did what the obituary calls postgraduate work at the Radiation Laboratory in Berkeley, studying synchrotron-produced electrons and cyclotron-produced mesons with cloud chambers, measuring the angular distribution of protons scattered by neutrons, and measuring the energy spectrum of delayed neutrons from oxygen-17, which gave information on that nucleus’s excited states.⁠[4]

The NIST staff profile has her hired into the Neutron Physics Section of the National Bureau of Standards in 1950. Her first experiments there used gamma rays from a cobalt-60 source and a 50 MeV betatron; after the bureau moved from Washington to Gaithersburg she worked with its 150 MeV linear accelerator. With John Hubbell she measured the albedo of 1 MeV photons reflected from semi-infinite slabs of water, aluminum, copper, tin and lead, and with William Dodge she ran experiments testing theories of bremsstrahlung, of the interaction of real and virtual photons with nuclei and of elastic photon scattering.⁠[19][4]

The obituary calls her an international leader in photonuclear physics who, using beams of electrons, positrons and neutrons from high-energy accelerators, for more than five decades worked on precision measurements of photoneutron production cross sections, on the scattering and absorption of photons by deformed nuclei and on the nuclear photoeffect in oriented nuclei. Her experiments showed that the giant resonance of ellipsoidal nuclei has two peaks, as her colleague the theorist Mike Danos had predicted; the two shared an office at the bureau for decades and more than once declined separate ones. After Everett Fuller retired she continued the bibliography of photonuclear reactions, which became the basis of the “Photonuclear Data Index” database.⁠[4]

The obituary also records several particular results: the angular distribution of neutron–proton scattering that she measured at Berkeley was neither isotropic in the center-of-mass system nor symmetric about 90°, the forward peak of protons suggesting charge exchange between neutron and proton; the albedo measurements were confirmed by Monte Carlo calculations done on a desk calculator; the Arenhoevel–Hayward theory of the scattering of plane-polarized photons by nuclear giant resonances was regarded as especially elegant, and Hayward, Barber and Sazama applied it in an experiment in which monochromatic plane-polarized photons from resonance fluorescence of the 15.1 MeV 1⁺ state of carbon-12 were scattered from natural cadmium, tin, tantalum, tungsten, platinum, gold and bismuth targets; and her work with Wolynec, Martins and Dodge on photonuclear and electronuclear reactions led to publications that the obituary calls well known throughout the world. The bibliography is available at the Centre for Photonuclear Experiments Data of the Institute of Nuclear Physics of Moscow State University, the National Nuclear Data Center of Brookhaven National Laboratory and the IAEA Nuclear Data Section in Vienna. H. William Koch’s recollections of 2006 likewise call the Arenhoevel–Hayward theory “Particularly elegant,” and their acknowledgments thank her for help in editing the manuscript.⁠[4][20]

The obituary has her becoming leader of the Nuclear Research Group in 1975, serving as deputy chief of the Nuclear Radiation Division from 1978 to 1980 and retiring from NIST in 1990 while maintaining collaborations with many scientists; the NIST staff profile has her as leader of the Neutron Physics Group from 1975 to 1986. She held visiting appointments at the Institute for Nuclear Physics of Goethe University (1966), the University of Melbourne (1969, as Sir Thomas Lyle Fellow), the University of Toronto (1975), the Max Planck Institute in Mainz (1982–1986), the Nuclear Physics Laboratory at Oxford (1985–1986), Duke University (1987 and 1990) and the Physics Institute of the University of Lund (1987).⁠[4][19]

In the 1970s President Richard NixonRichard NixonRichard Nixon (1913–1994) was an American politician who represented California in the U.S. House and Senate, served as vice president from 1953 to 1961 and was the 37th president of the United States from 1969 to 1974. His administration opened relations with China, signed strategic arms limitation agreements with the Soviet Union and ended U.S. involvement in the Vietnam War; he resigned over the Watergate scandal on August 9, 1974, the only U.S. president to do so.Open the full entry selected her for the General Advisory Committee to the Atomic Energy Commission, and she also served on the Advisory Screening Committee in Physics for the Committee on International Exchange of Persons (Senior Fulbright-Hays Program) and on Maryland Governor Mandel’s Science Advisory Council, which assists the governor with scientific problems. She received the Department of Commerce Silver Medal (1958) and Gold Medal (1971), the Federal Women’s Award (1975) and the Samuel Wesley Stratton Award (1980), became an NBS Fellow in 1987, was added to the NIST Portrait Gallery of Distinguished Scientists, Engineers, and Administrators in 1995, and was a Fellow of the American Physical Society. The gallery’s 2020 list gives her tenure as 1950–1990 and 1995 as the year of her induction.⁠[4][19][16]

The obituary records her remark that she dressed professionally so as not to be a distraction during experiments; she entered physics when very few women were in the field, believed that she had to excel to be recognized, and at various times met gender discrimination at the bureau. After retiring fully she took evening classes at American University in politics, international relations, Spanish and Italian. The obituary calls her a natural leader whose extraordinary accomplishments and value to the bureau her peers and direct supervisors recognized and who travelled widely to run experiments and to lecture; she said that she took the classes because she still wanted to learn. Colleagues around the world sent condolences and thanks after her death.⁠[4]

She died of heart disease at her home in Chevy Chase, Maryland, on March 2, 2020. Her obituary states that she was predeceased by her husband and two sons.⁠[4]

National Institute of Standards and Technology: Official website: https://www.nist.gov/ (opens in a new window).⁠[21]

University of Maryland: Official website: https://umd.edu/ (opens in a new window).⁠[22]