James Cronin

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James Cronin
Cronin at the 2010 Lindau Nobel Laureate Meeting
James Watson Cronin

(1931-09-29)September 29, 1931
DiedAugust 25, 2016(2016-08-25) (aged 84)
Alma mater Southern Methodist University
University of Chicago
Known for Nuclear physics
Awards E. O. Lawrence Award (1976)
Nobel Prize in Physics (1980)
John Price Wetherill Medal
National Medal of Science
Scientific career
Fields Physics
Institutions University of Chicago

James Watson Cronin (September 29, 1931 – August 25, 2016 [1] ) was an American particle physicist. [2] [3]

Particle physics Branch of physics

Particle physics is a branch of physics that studies the nature of the particles that constitute matter and radiation. Although the word particle can refer to various types of very small objects, particle physics usually investigates the irreducibly smallest detectable particles and the fundamental interactions necessary to explain their behaviour. By our current understanding, these elementary particles are excitations of the quantum fields that also govern their interactions. The currently dominant theory explaining these fundamental particles and fields, along with their dynamics, is called the Standard Model. Thus, modern particle physics generally investigates the Standard Model and its various possible extensions, e.g. to the newest "known" particle, the Higgs boson, or even to the oldest known force field, gravity.


Cronin was born in Chicago, Illinois, and attended Southern Methodist University in Dallas, Texas. He and co-researcher Val Logsdon Fitch were awarded the 1980 Nobel Prize in Physics for a 1964 experiment that proved that certain subatomic reactions do not adhere to fundamental symmetry principles. Specifically, they proved, by examining the decay of kaons, that a reaction run in reverse does not merely retrace the path of the original reaction, which showed that the interactions of subatomic particles are not invariant under time reversal. Thus the phenomenon of CP violation was discovered. [4] [5] [6] [7]

Southern Methodist University Private university in Dallas, Texas, United States

Southern Methodist University is a private research university in metropolitan Dallas, Texas with its main campus located in University Park. SMU also operates satellite campuses in Plano, Texas and Taos, New Mexico.

Val Logsdon Fitch American physicist

Val Logsdon Fitch was an American nuclear physicist who, with co-researcher James Cronin, was awarded the 1980 Nobel Prize in Physics for a 1964 experiment using the Alternating Gradient Synchrotron at Brookhaven National Laboratory that proved that certain subatomic reactions do not adhere to fundamental symmetry principles. Specifically, they proved, by examining the decay of K-mesons, that a reaction run in reverse does not retrace the path of the original reaction, which showed that the reactions of subatomic particles are not indifferent to time. Thus the phenomenon of CP violation was discovered. This demolished the faith that physicists had that natural laws were governed by symmetry.

Nobel Prize in Physics One of the five Nobel Prizes established in 1895 by Alfred Nobel

The Nobel Prize in Physics is a yearly award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions for humankind in the field of physics. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901; the others being the Nobel Prize in Chemistry, Nobel Prize in Literature, Nobel Peace Prize, and Nobel Prize in Physiology or Medicine.

Cronin received the Ernest Orlando Lawrence Award in 1976 for major experimental contributions to particle physics including fundamental work on weak interactions culminating in the discovery of asymmetry under time reversal. In 1999, he was awarded the National Medal of Science. [8]

Ernest Orlando Lawrence Award award

The Ernest Orlando Lawrence Award was established in 1959 in honor of a scientist who helped elevate American physics to the status of world leader in the field.

National Medal of Science award

The National Medal of Science is an honor bestowed by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral and social sciences, biology, chemistry, engineering, mathematics and physics. The twelve member presidential Committee on the National Medal of Science is responsible for selecting award recipients and is administered by the National Science Foundation (NSF).

Cronin was Professor Emeritus at the University of Chicago and a spokesperson emeritus for the Auger project. He was a member of the Board of Sponsors of the Bulletin of the Atomic Scientists.

Professor academic rank at universities and other post-secondary education and research institutions in most countries

Professor is an academic rank at universities and other post-secondary education and research institutions in most countries. Literally, professor derives from Latin as a "person who professes" being usually an expert in arts or sciences, a teacher of the highest rank.

Emeritus, in its current usage, is an adjective used to designate a retired chairman, professor, pastor, bishop, pope, director, president, prime minister, rabbi, emperor, or other person.

University of Chicago Private research university in Chicago, Illinois, United States

The University of Chicago is a private research university in Chicago, Illinois. Founded in 1890, the school is located on a 217-acre campus in Chicago's Hyde Park neighborhood, near Lake Michigan. The University of Chicago holds top-ten positions in various national and international rankings.

Education and early life

James Cronin was born on September 29, 1931. His father, James Farley Cronin, was a graduate student of classical languages at the University of Chicago. After his father had obtained his doctorate the family first moved to Alabama, and later in 1939 to Dallas, Texas, where his father became a professor of Latin and Greek at Southern Methodist University. After high school Cronin stayed in Dallas and obtained an undergraduate degree at Southern Methodist University in physics and mathematics in 1951. [9]

Dallas City in Texas, United States

Dallas, officially the City of Dallas, is a city in the U.S. state of Texas and the seat of Dallas County, with portions extending into Collin, Denton, Kaufman and Rockwall counties. With an estimated 2017 population of 1,341,075, it is the ninth most-populous city in the U.S. and third in Texas after Houston and San Antonio. It is also the eighteenth most-populous city in North America as of 2015. Located in North Texas, the city of Dallas is the main core of the largest metropolitan area in the Southern United States and the largest inland metropolitan area in the U.S. that lacks any navigable link to the sea. It is the most populous city in the Dallas–Fort Worth metroplex, the fourth-largest metropolitan area in the country at 7.5 million people as of 2018. The city's combined statistical area is the seventh-largest in the U.S. as of 2017, with 7,846,293 residents.

Texas State of the United States of America

Texas is the second largest state in the United States by both area and population. Geographically located in the South Central region of the country, Texas shares borders with the U.S. states of Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the west, and the Mexican states of Chihuahua, Coahuila, Nuevo León, and Tamaulipas to the southwest, and has a coastline with the Gulf of Mexico to the southeast.

For graduate school Cronin moved back to Illinois to attend the University of Chicago. His teachers there included Nobel Prize laureates Enrico Fermi, Maria Mayer, Murray Gell-Mann and Subrahmanyan Chandrasekhar. He wrote his thesis on experimental nuclear physics under supervision of Samuel K. Allison.

Enrico Fermi Nuclear physicist

Enrico Fermi was an Italian and naturalized-American physicist and the creator of the world's first nuclear reactor, the Chicago Pile-1. He has been called the "architect of the nuclear age" and the "architect of the atomic bomb". He was one of very few physicists to excel in both theoretical physics and experimental physics. Fermi held several patents related to the use of nuclear power, and was awarded the 1938 Nobel Prize in Physics for his work on induced radioactivity by neutron bombardment and for the discovery of transuranium elements. He made significant contributions to the development of statistical mechanics, quantum theory, and nuclear and particle physics.

Murray Gell-Mann American physicist

Murray Gell-Mann is an American physicist who received the 1969 Nobel Prize in physics for his work on the theory of elementary particles. He is the Robert Andrews Millikan Professor of Theoretical Physics Emeritus at the California Institute of Technology, a distinguished fellow and co-founder of the Santa Fe Institute, a professor of physics at the University of New Mexico, and the Presidential Professor of Physics and Medicine at the University of Southern California.

Subrahmanyan Chandrasekhar American physicist

Subrahmanyan Chandrasekhar was an Indian American astrophysicist who spent his professional life in the United States. He was awarded the 1983 Nobel Prize for Physics with William A. Fowler for "...theoretical studies of the physical processes of importance to the structure and evolution of the stars". His mathematical treatment of stellar evolution yielded many of the current theoretical models of the later evolutionary stages of massive stars and black holes. The Chandrasekhar limit is named after him.

Research and career

After obtaining his doctorate in 1955, Cronin joined the group of Rodney L. Cool and Oreste Piccioni at Brookhaven National Laboratory, where the new Cosmotron particle accelerator had just been completed. There he started to study parity violation in the decay of hyperon particles. During that time he also met Val Fitch, who brought him to Princeton University in Fall 1958. After Cosmotron underwent magnet failure, Cronin and the Brookhaven group moved to Bevatron at the University of California, Berkeley during the first half of 1958. Cronin and Fitch studied the decays of neutral K mesons, in which they discovered CP violation in 1964. This discovery earned the duo the 1980 Nobel Prize in Physics. [9]

After the discovery, Cronin spent a year in France at the Centre d'Études Nucléaires at Saclay. After returning to Princeton he continued studying the neutral CP violating decay modes of the long-lived neutral K meson. In 1971, he moved back to the University of Chicago to become a full professor. This was attractive for him because of a new 400 GeV particle accelerator being built at nearby Fermilab. [9]

When he moved to Chicago, he began a long series of experiments on particle production at high transverse momentum. With physicist Pierre Piroue and colleagues we learned about many things. These are summarized in Physical Review D, vol 19, page 764 (1977). Following these experiments Cronin took a sabbatical at CERN in 1982–83, where he performed an experiment to measure of the lifetime of the neutral pion (Physics Letters vol 158 B page 81, 1985). He then switched to the study of cosmic rays. The first was a series of measurements looking for point sources of cosmic rays. No sources were found. A summary of the measurements was published in Physical Review D vol 55 page 1714 (1997). In 1998 he joined the faculty at the University of Utah on a half-time basis to work on ultra-high-energy cosmic ray physics and to jumpstart the Pierre Auger Observatory project. [10] His appointment was to last five years, but he left after a year to continue gathering international support for the Observatory with Alan Watson [3] and Murat Boratav. [11]


Personal life

While in graduate school he also met his wife, Annette Martin, whom he married in 1954. [9] She was the Director of Special Events at the University of Chicago. [12] They have three children: two daughters, Cathryn (1955) and Emily (1959), and a son, Daniel (1971). [9] In June 2005 Annette Martin died of complications of Parkinson's disease. She was 71. [12]

In November 2006 he married Carol Champlin.

In May 2011 his daughter Cathryn Cranston died of leukemia at age 54.

Cronin died on August 25, 2016, at the age of 84. [3] [2] [13] [14]

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  1. http://chicago.suntimes.com/news/nobel-laureate-u-of-c-professor-emeritus-james-cronin-dead-at-84/
  2. 1 2 Watson, Alan (2016). "James Cronin (1931–2016) Particle physicist who helped to explain the dominance of matter in the Universe". Nature . London: Springer Nature. 537 (7621): 489–489. Bibcode:2016Natur.537..489W. doi:10.1038/537489a.
  3. 1 2 3 Watson, Alan (2018). "James Watson Cronin. 29 September 1931 — 25 August 2016". Biographical Memoirs of Fellows of the Royal Society : 20180021. doi:10.1098/rsbm.2018.0021. ISSN   0080-4606.
  4. Harrison, Theresa (August 2014). "Anniversary: CP violation's early days" (PDF). CERN Courier. 54 (6): 21–22.
  5. Harrison, Paul (November 2014). "Anniversary: CP violation: past, present and future" (PDF). CERN Courier. 54 (9): 32–34.
  6. Ellis, John (October 1999). "Why does CP violation matter to the universe?". CERN Courier. 39 (8): 24–26.
  7. Bauer, Gerry (June 1999). "In hot pursuit of CP violation". CERN Courier. 39 (5): 22–25.
  8. National Science Foundation - The President's National Medal of Science
  9. 1 2 3 4 5 Cronin, James (1980). "Autobiography". The Nobel Prize in Physics 1980: James Cronin, Val Fitch. The Nobel Foundation . Retrieved 22 May 2012.
  10. Browne, Malcolm W. (18 August 1998). "Scientist at Work: Dr. James W. Cronin; Looking for a Few Good Particles From Outer Space". The New York Times. Retrieved 22 June 2017.
  11. Bauman, Joe (22 April 1999). "Nobel Prize winner Cronin to take a year off from U." Deseret News. Retrieved 22 June 2017.
  12. 1 2 "Annette Martin Cronin directed Special Events, organized Chicago's first Humanities Open House". chronicle.uchicago.edu. Retrieved 2016-01-23.
  13. https://www.washingtonpost.com/national/health-science/james-cronin-nobel-laureate-who-broke-seemingly-inviolable-laws-of-subatomic-particles-dies-at-84/2016/08/28/4f4cb70a-6c62-11e6-8225-fbb8a6fc65bc_story.html
  14. https://www.nytimes.com/2016/08/31/science/james-cronin-who-explained-why-matter-survived-the-big-bang-dies-at-84.html?_r=0