Cronin at the 2010 Lindau Nobel Laureate Meeting
James Watson Cronin
September 29, 1931
Chicago, Illinois, U.S.
|Died||August 25, 2016 84) (aged|
Saint Paul, Minnesota, U.S.
|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
|Institutions||University of Chicago|
James Watson Cronin (September 29, 1931 – August 25, 2016) was an American particle physicist.
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.
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 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.
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.
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.
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 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.
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.
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.
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 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 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 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 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.
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.
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.
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.His appointment was to last five years, but he left after a year to continue gathering international support for the Observatory with Alan Watson and Murat Boratav.
While in graduate school he also met his wife, Annette Martin, whom he married in 1954.She was the Director of Special Events at the University of Chicago. They have three children: two daughters, Cathryn (1955) and Emily (1959), and a son, Daniel (1971). In June 2005 Annette Martin died of complications of Parkinson's disease. She was 71.
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.
In particle physics, mesons are hadronic subatomic particles composed of one quark and one antiquark, bound together by strong interactions. Because mesons are composed of quark subparticles, they have physical size, notably a diameter of roughly one femtometer, which is about 1.2 times the size of a proton or neutron. All mesons are unstable, with the longest-lived lasting for only a few hundredths of a microsecond. Charged mesons decay to form electrons and neutrinos. Uncharged mesons may decay to photons. Both of these decays imply that color is no longer a property of the byproducts.
In particle physics, the weak interaction, which is also often called the weak force or weak nuclear force, is the mechanism of interaction between subatomic particles that is responsible for the radioactive decay of atoms. The weak interaction serves an essential role in nuclear fission, and the theory regarding it in terms of both its behavior and effects is sometimes called quantum flavordynamics (QFD). However, the term QFD is rarely used because the weak force is better understood in terms of electroweak theory (EWT). In addition to this, QFD is related to quantum chromodynamics (QCD), which deals with the strong interaction, and quantum electrodynamics (QED), which deals with the electromagnetic force.
In particle physics, a pion is any of three subatomic particles:
. Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the lightest mesons and, more generally, the lightest hadrons. They are unstable, with the charged pions
decaying with a mean lifetime of 26.033 nanoseconds, and the neutral pion
decaying with a much shorter lifetime of 8.4×10−17 seconds. Charged pions most often decay into muons and muon neutrinos, while neutral pions generally decay into gamma rays.
A timeline of atomic and subatomic physics.
In particle physics, a kaon, also called a K meson and denoted
, is any of a group of four mesons distinguished by a quantum number called strangeness. In the quark model they are understood to be bound states of a strange quark and an up or down antiquark.
Burton Richter was an American physicist. He led the Stanford Linear Accelerator Center (SLAC) team which co-discovered the J/ψ meson in 1974, alongside the Brookhaven National Laboratory (BNL) team led by Samuel Ting for which they won Nobel Prize for Physics in 1976. This discovery was part of the so-called November Revolution of particle physics. He was the SLAC director from 1984 to 1999.
The BaBar experiment, or simply BaBar, is an international collaboration of more than 500 physicists and engineers studying the subatomic world at energies of approximately ten times the rest mass of a proton (~10 GeV). Its design was motivated by the investigation of Charge Parity violation. BaBar is located at the SLAC National Accelerator Laboratory, which is operated by Stanford University for the Department of Energy in California.
Jack Steinberger is an American physicist who, along with Leon M. Lederman and Melvin Schwartz, received the 1988 Nobel Prize in Physics for the discovery of the muon neutrino.
The LHCb experiment is one of seven particle physics detector experiments collecting data at the Large Hadron Collider at CERN. LHCb is a specialized b-physics experiment, designed primarily to measure the parameters of CP violation in the interactions of b-hadrons. Such studies can help to explain the matter-antimatter asymmetry of the Universe. The detector is also able to perform measurements of production cross sections, exotic hadron spectroscopy, charm physics and electroweak physics in the forward region. The LHCb collaboration, who built, operate and analyse data from the experiment, is composed of approximately 1260 people from 74 scientific institutes, representing 16 countries. As of 2017, the spokesperson for the collaboration is Giovanni Passaleva. The experiment is located at point 8 on the LHC tunnel close to Ferney-Voltaire, France just over the border from Geneva. The (small) MoEDAL experiment shares the same cavern.
In physics, the baryon asymmetry problem, also known as the matter asymmetry problem or the matter-antimatter asymmetry problem, is the observed imbalance in baryonic matter and antibaryonic matter in the observable universe. Neither the standard model of particle physics, nor the theory of general relativity provides a known explanation for why this should be so, and it is a natural assumption that the universe be neutral with all conserved charges. The Big Bang should have produced equal amounts of matter and antimatter. Since this does not seem to have been the case, it is likely some physical laws must have acted differently or did not exist for matter and antimatter. Several competing hypotheses exist to explain the imbalance of matter and antimatter that resulted in baryogenesis. However, there is as of yet no consensus theory to explain the phenomenon. As remarked in a 2012 research paper, "The origin of matter remains one of the great mysteries in physics."
The Lambda baryons are a family of subatomic hadron particles containing one up quark, one down quark, and a third quark from a higher flavour generation, in a combination where the quantum wave function changes sign upon the flavour of any two quarks being swapped. They are thus baryons, with total isospin of 0, and have either neutral electric charge or the elementary charge +1.
Neutral B meson oscillations is one of the manifestations of the neutral particle oscillation, a fundamental prediction of the Standard Model of particle physics. It is the phenomenon of B mesons changing between their matter and antimatter forms before their decay. The
s meson can exist as either a bound state of a strange antiquark and a bottom quark, or a strange quark and bottom antiquark. The oscillations in the neutral B sector are analogous to the phenomena that produces long and short-lived neutral kaons.
Gerson Goldhaber was a German-born American particle physicist and astrophysicist. He was one of the discoverers of the J/ψ meson which confirmed the existence of the charm quark. He worked at Lawrence Berkeley National Laboratory with the Supernova Cosmology Project, and was a professor of physics emeritus at the University of California, Berkeley as well as a professor at Berkeley's graduate school in astrophysics.
In particle physics, CP violation is a violation of CP-symmetry : the combination of C-symmetry and P-symmetry. CP-symmetry states that the laws of physics should be the same if a particle is interchanged with its antiparticle while its spatial coordinates are inverted. The discovery of CP violation in 1964 in the decays of neutral kaons resulted in the Nobel Prize in Physics in 1980 for its discoverers James Cronin and Val Fitch.
Anthony Ichiro Sanda is a Japanese-American particle physicist. Along with Ikaros Bigi, he was awarded the 2004 Sakurai Prize for his work on CP violation and B meson decays.
NA31 is a CERN experiment which was proposed in 1982 as a "Measurement of |η00 /η+-|2 by the CERN-Edinburgh-Mainz-Pisa-Siegen collaboration. It took data between 1986 and 1989, using a proton beam from the SPS through the K4 neutral beam-line. Its aim was to experimentally prove direct CP-violation.
Maria Fidecaro is an Italian experimental physicist with a focus on particle physics. She has spent most of her career at CERN, where she today has the status of honorary member of the personnel.
SooKyung Choi is a South Korean particle physicist at Gyeongsang National University. She is part of the Belle experiment and was the first to observe the X(3872) meson in 2003. She won the 2017 Ho-Am Prize in Science.