View source for James Cronin

{{Short description|American particle physicist}}
{{For|the rugby player|James Cronin (rugby union)}}
{{Similar names|Jim Cronin (disambiguation){{!}}Jim Cronin}} 
{{Infobox scientist
| name              = James Cronin
| image             = James-cronin.jpg
| caption           = Cronin at the 2010 [[Nobel Laureate Meetings at Lindau|Lindau Nobel Laureate Meeting]]
| birth_name        = James Watson Cronin
| birth_date        = {{Birth date|1931|09|29}}
| birth_place       = [[Chicago, Illinois]], U.S.
| death_date        = {{death date and age|2016|08|25|1931|9|29}}
| death_place       = [[Saint Paul, Minnesota]], U.S.
| spouse = {{marriage| 
Annette Martin|1954}}
| children = 3
| field             = [[Physics]]
| work_institutions = [[University of Chicago]]
[[University of Utah]]
| alma_mater        = {{nowrap|[[Southern Methodist University]]}}<br/>[[University of Chicago]]
| known_for         = [[Nuclear physics]]
| prizes            = [[Ernest Orlando Lawrence Award|E. O. Lawrence Award]] (1976)<br/>[[Nobel Prize in Physics]] (1980)<br/>[[John Price Wetherill Medal]]<br/>[[National Medal of Science]]
}}
'''James Watson Cronin''' (September 29, 1931 – August 25, 2016<ref>{{Cite web | url=http://chicago.suntimes.com/news/nobel-laureate-u-of-c-professor-emeritus-james-cronin-dead-at-84/ |title = Nobel laureate, U of C professor emeritus James Cronin dead at 84|date = 2016-08-28}}</ref>) was an American [[particle physics|particle physicist]].<ref name=NatureObituary>{{cite journal|last1=Watson|first1=Alan|author-link=Alan Andrew Watson|title=James Cronin (1931–2016) Particle physicist who helped to explain the dominance of matter in the Universe|journal=[[Nature (journal)|Nature]]|location=London|publisher=[[Springer Nature]]|volume=537|issue=7621|year=2016|pages=489|doi=10.1038/537489a|pmid=27652559|bibcode=2016Natur.537..489W|doi-access=free}}</ref><ref name=rsbm>{{cite journal|last1=Watson|first1=Alan|author-link1=Alan Andrew Watson|title=James Watson Cronin. 29 September 1931 — 25 August 2016|journal=[[Biographical Memoirs of Fellows of the Royal Society]]|volume=65|year=2018|pages=47–70|issn=0080-4606|doi=10.1098/rsbm.2018.0021|doi-access=free}}</ref>

Cronin 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 [[kaon]]s, that a reaction run in reverse does not merely retrace the path of the original reaction, which showed that the interactions of [[subatomic particle]]s are not invariant under time reversal. Thus the phenomenon of [[CP violation]] was discovered.<ref>{{cite journal|last1=Harrison|first1=Theresa|title=Anniversary: CP violation's early days|journal=CERN Courier|date=August 2014|volume=54|issue=6|pages=21–22|url=http://iopp.fileburst.com/ccr/archive/CERNCourier2014JulAug-digitaledition.pdf|access-date=2015-03-31|archive-date=2020-10-20|archive-url=https://web.archive.org/web/20201020092926/http://iopp.fileburst.com/ccr/archive/CERNCourier2014JulAug-digitaledition.pdf|url-status=dead}}</ref><ref>{{cite journal|last1=Harrison|first1=Paul|title=Anniversary: CP violation: past, present and future|journal=CERN Courier|date=November 2014|volume=54|issue=9|pages=32–34|url=http://iopp.fileburst.com/ccr/archive/CERNCourier2014Nov-digitaledition.pdf|access-date=2015-03-31|archive-date=2020-10-20|archive-url=https://web.archive.org/web/20201020084230/http://iopp.fileburst.com/ccr/archive/CERNCourier2014Nov-digitaledition.pdf|url-status=dead}}</ref><ref>{{cite journal|last1=Ellis|first1=John|title=Why does CP violation matter to the universe?|journal=CERN Courier|date=October 1999|volume=39|issue=8|pages=24–26|url=https://cds.cern.ch/record/1732992}}</ref><ref>{{cite journal|last1=Bauer|first1=Gerry|title=In hot pursuit of CP violation|journal=CERN Courier|date=June 1999|volume=39|issue=5|pages=22–25|url=https://cds.cern.ch/record/1732952}}</ref>{{Excessive citations inline|date=September 2021}}

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]].<ref>[https://www.nsf.gov/od/nms/recip_details.cfm?recip_id=93 National Science Foundation - The President's National Medal of Science]</ref>

Cronin was [[Professor]] [[Emeritus]] at the [[University of Chicago]] winning the prestigious [[Quantrell Award]]<ref>{{Cite web|url=https://www.uchicago.edu/about/accolades/35/|title = Llewellyn John and Harriet Manchester Quantrell Awards for Excellence in Undergraduate Teaching}}</ref> and a spokesperson emeritus for the [[Pierre Auger Observatory|Auger]] project. He was a member of the Board of Sponsors of the [[Bulletin of the Atomic Scientists]].

==Education and early life==
James Cronin was born in [[Chicago]] 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 SMU in physics and mathematics in 1951.<ref name="autobio">{{cite web|last=Cronin|first=James |title=Autobiography |url=https://www.nobelprize.org/nobel_prizes/physics/laureates/1980/cronin-autobio.html|work=The Nobel Prize in Physics 1980: James Cronin, Val Fitch|publisher=[[The Nobel Foundation]]|access-date=22 May 2012|author-link=James Cronin|year=1980}}</ref> He is of Irish descent, with his Irish ancestors immigrating from County Cork, Ireland.<ref>{{Cite journal |last=Watson |first=Alan |date=December 2018 |title=James Watson Cronin. 29 September 1931 — 25 August 2016 |url=https://royalsocietypublishing.org/doi/10.1098/rsbm.2018.0021 |journal=Biographical Memoirs of Fellows of the Royal Society |language=en |volume=65 |pages=47–70 |doi=10.1098/rsbm.2018.0021 |issn=0080-4606|url-access=subscription }}</ref>

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

==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 meson]]s, in which they discovered [[CP violation]] in 1964. This discovery earned the duo the 1980 [[Nobel Prize in Physics]].<ref name="autobio"/>

After the discovery, Cronin spent a year in [[France]] at the [[CEA Saclay|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&nbsp;GeV particle accelerator being built at nearby [[Fermilab]].<ref name="autobio"/> He received the [[Quantrell Award]].<ref name="Prize">{{cite web|title=Llewellyn John and Harriet Manchester Quantrell Awards for Excellence in Undergraduate Teaching|url=https://www.uchicago.edu/who-we-are/global-impact/accolades/llewellyn-john-and-harriet-manchester-quantrell-awards-for-excellence-in-undergraduate-teaching|website=UChicago}}</ref>

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 [[Pion|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.<ref>{{cite news|last1=Browne|first1=Malcolm W.|title=Scientist at Work: Dr. James W. Cronin; Looking for a Few Good Particles From Outer Space|url=https://www.nytimes.com/1998/08/18/science/scientist-work-dr-james-w-cronin-looking-for-few-good-particles-outer-space.html|access-date=22 June 2017|work=The New York Times|date=18 August 1998}}</ref> His appointment was to last five years, but he left after a year to continue gathering international support for the Observatory with [[Alan Andrew Watson|Alan Watson]]<ref name=rsbm/> and Murat Boratav.<ref>{{cite news|last1=Bauman|first1=Joe|title=Nobel Prize winner Cronin to take a year off from U.|url=https://www.deseret.com/1999/4/22/19441388/nobel-prize-winner-cronin-to-take-a-year-off-from-u/|access-date=22 June 2017|work=Deseret News|date=22 April 1999|language=en}}</ref>

Cronin is one of the 20 American recipients of the Nobel Prize in Physics to sign a letter addressed to President [[George W. Bush]] in May 2008, urging him to "reverse the damage done to basic science research in the Fiscal Year 2008 Omnibus Appropriations Bill" by requesting additional emergency funding for the [[United States Department of Energy|Department of Energy]]'s [[Office of Science]], the [[National Science Foundation]], and the [[National Institute of Standards and Technology]].<ref>{{Cite web|title=A Letter from America's Physics Nobel Laureates|url=https://fire.pppl.gov/nobel_bush_fy08_050808.pdf}}</ref>

===Publications===
*Banner, M.; Cronin, J. W.; Liu, J. K.; & J. E. Pilcher. [https://www.osti.gov/biblio/4479380-measurement-branching-ratio-sub-yields-gamma-gamma-sub-yields-pi  "Measurement of the Branching Ratio K{sub L} → γ γ / K{sub L} → 3π{sup 0}"], Palmer Physical Laboratory, [[Princeton University]], [[United States Department of Energy]] (through predecessor agency the [[United States Atomic Energy Commission|Atomic Energy Commission]]), (August 12, 1968).
*Banner, M.; Cronin, J. W.; Liu, J. K.; & J. E. Pilcher. [https://www.osti.gov/biblio/4492551-measurement-branching-ratio-sub-yields-pi-sup-sub-yields-pi  "Measurement of the Branching Ratio K{sub L} → 2π{sup 0} / K{sub L} → 3π{sup 0}"], Palmer Physical Laboratory, [[Princeton University]], [[United States Department of Energy]] (through predecessor agency the [[United States Atomic Energy Commission|Atomic Energy Commission]]), (August 14, 1968).
*Cronin, J. W.; Frisch, H. J.; Shochet, M. J.; Boymond, J. P.; Mermod, R.; Piroue, P. A.; & R. L. Sumner. [https://www.osti.gov/biblio/4260617-atomic-number-dependence-hadron-production-large-transverse-momentum-gev-proton-nucleus-collisions  "Atomic Number Dependence of Hadron Production at Large Transverse Momentum in 300 GeV Proton&mdash;Nucleus Collisions"], Enrico Fermi Institute, [[University of Chicago]], Joseph Henry Laboratories, [[Princeton University]], [[United States Department of Energy]] (through predecessor agency the [[United States Atomic Energy Commission|Atomic Energy Commission]]), National Science Foundation, (July 15, 1974).
*Brun, T. O.; Carpenter, J. M.; Krohn, V. E.; Ringo, G. R.; Cronin, J. W.; Dombeck, T. W.; Lynn, J. W.; & S. A. Werner. [https://www.osti.gov/biblio/5628749-measurement-ultracold-neutrons-produced-using-doppler-shifted-bragg-reflection-pulsed-neutron-source  "Measurement of Ultracold Neutrons Produced by Using Doppler-shifted Bragg Reflection at a Pulsed-neutron Source"], [[Argonne National Laboratory]], [[University of Chicago]], [[University of Maryland, College Park]], [[University of Missouri]], [[United States Department of Energy]], (1979).
*Cronin, J. W.; Deshpande, N. G.; Kane, G. L.; Luth, V. C.; Odian, A. C.; Machacek, M. E.; Paige, F.; Schmidt, M. P.; Slaughter, J.; & G. H. Trilling. [https://www.osti.gov/biblio/6124405-report-working-group-cp-violation-rare-decays  "Report of the Working Group on CP Violation and Rare Decays"], [[University of Chicago]], [[University of Oregon]], [[University of Michigan]], [[Stanford Linear Accelerator Center]] (SLAC), [[Northeastern University]], [[Brookhaven National Laboratory]] (BNL), [[United States Department of Energy]], (October 1984).
* Abraham J., Cronin J. W. et al., Observation of suppression of the Flux of Cosmic Rays above 4x10**19 eV., Phys Rev Letters vol 101, p 061101, (2008).

==Personal life==
While in graduate school he also met his wife, Annette Martin, whom he married in 1954.<ref name="autobio"/> She was the Director of Special Events at the University of Chicago.<ref name="chronicle.uchicago.edu">{{Cite web|title = Annette Martin Cronin directed Special Events, organized Chicago's first Humanities Open House|url = http://chronicle.uchicago.edu/050714/obitcronin.shtml|website = chronicle.uchicago.edu|access-date = 2016-01-23}}</ref> They have three children: two daughters, Cathryn (b. 1955) and Emily (b. 1959), and a son, Daniel (b. 1971).<ref name="autobio"/> In June 2005 Annette Martin died of complications of Parkinson's disease. She was 71.<ref name="chronicle.uchicago.edu"/>

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.<ref name=rsbm/><ref name=NatureObituary/><ref>{{Cite news | url=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 |title = James Cronin, Nobel laureate who overturned long-accepted beliefs about the fundamental symmetry of laws of physics , dies at 84| newspaper=[[The Washington Post]] }}</ref><ref>{{Cite news | url=https://www.nytimes.com/2016/08/31/science/james-cronin-who-explained-why-matter-survived-the-big-bang-dies-at-84.html?_r=0 | title=James Cronin, Who Explained Why Matter Survived the Big Bang, Dies at 84| newspaper=The New York Times| date=2016-08-31| last1=Roberts| first1=Sam}}</ref>

== References ==
{{Reflist}}

==External links==
* {{Nobelprize}} including the Nobel Lecture, December 8, 1980 ''CP Symmetry Violation – The Search for Its Origin''
* [http://www.nobel-winners.com/Physics/james_watson_cronin.html James Watson Cronin] on Nobel-winners.com
* [https://web.archive.org/web/20051224051321/http://eraserall.bravehost.com/swq/cronin-autobio.html the discovery of violations of fundamental symmetry principles in the decay of neutral K-mesons.]
* [https://web.archive.org/web/20081012072551/http://physics.uchicago.edu/research/areas/astro_cosmo_x.html#Cronin Short biography at the University of Chicago]
* {{INSPIRE-HEP author}}

{{Nobel Prize in Physics Laureates 1976-2000}}
{{1980 Nobel Prize winners}}

{{FRS 2007}}
{{Authority control}}

{{DEFAULTSORT:Cronin, James Watson}}
[[Category:1931 births]]
[[Category:2016 deaths]]
[[Category:University of Chicago alumni]]
[[Category:American Nobel laureates]]
[[Category:American nuclear physicists]]
[[Category:People associated with CERN]]
[[Category:Foreign members of the Royal Society]]
[[Category:Foreign members of the Russian Academy of Sciences]]
[[Category:Members of the United States National Academy of Sciences]]
[[Category:National Medal of Science laureates]]
[[Category:Nobel laureates in Physics]]
[[Category:University of Chicago faculty]]
[[Category:Weak interaction physicists]]
[[Category:Sloan Research Fellows]]
[[Category:University of Utah faculty]]
[[Category:Fellows of the American Physical Society]]