Editing Neutrino (section)

=== Direct detection ===
[[File:Clyde Cowan.jpg|thumb|upright=1.1|Fred Reines and Clyde Cowan conducting the neutrino experiment c. 1956]]
In 1942, [[Wang Ganchang]] first proposed the use of [[Electron capture|beta capture]] to experimentally detect neutrinos.<ref>
{{cite journal
 |last=Wang |first=Kan Chang |author-link=Wang Ganchang
 |year=1942
 |title=A suggestion on the detection of the neutrino
 |journal=[[Physical Review]]
 |volume=61 |issue=1–2 |page=97
 |bibcode=1942PhRv...61...97W |doi=10.1103/PhysRev.61.97
}}
</ref> In the 20&nbsp;July 1956 issue of [[Science (journal)|''Science'']], [[Clyde Cowan]], [[Frederick Reines]], Francis B. "Kiko" Harrison, Herald W. Kruse, and Austin D. McGuire published confirmation that they had detected the neutrino,<ref>
{{cite journal
 |last1=Cowan |first1=Clyde L. Jr. |author1-link=Clyde Cowan
 |last2=Reines |first2=Frederick |author2-link=Frederick Reines
 |last3=Harrison |first3=Francis B. "Kiko"
 |last4=Kruse |first4=Herald W.
 |last5=McGuire |first5=Austin D.
 |year=1956
 |title=Detection of the free neutrino: A confirmation
 |journal=[[Science (journal)|Science]]
 |volume=124 |issue=3212 |pages=103–104
 |bibcode=1956Sci...124..103C
 |doi=10.1126/science.124.3212.103 |pmid=17796274
}}
</ref><ref>
This source reproduces the 1956 paper:<br />{{cite book |last=Winter |first=Klaus |url=https://books.google.com/books?id=v_tiL2NlfvMC&pg=PA38 |title=Neutrino Physics |publisher=[[Cambridge University Press]] |year=2000 |isbn=978-0-521-65003-8 |pages=38&nbsp;ff}}
</ref> a result that was rewarded almost forty years later with the [[Nobel Prize in Physics|1995 Nobel Prize]].<ref>
{{cite web
 |title=The Nobel Prize in Physics
 |year=1995
 |publisher=[[The Nobel Foundation]]
 |url=http://nobelprize.org/nobel_prizes/physics/laureates/1995/
 |access-date=29 June 2010
 |archive-date=30 June 2018
 |archive-url=https://web.archive.org/web/20180630025246/https://www.nobelprize.org/nobel_prizes/physics/laureates/1995/
 |url-status=live
}}</ref>

In this experiment, now known as the [[Cowan–Reines neutrino experiment]], antineutrinos created in a nuclear reactor by beta decay reacted with protons to produce [[neutron]]s and positrons:
: {{math| {{SubatomicParticle|Electron antineutrino}} + {{SubatomicParticle|Proton+}} → {{SubatomicParticle|Neutron0}} + {{SubatomicParticle|Electron+}} }}

The positron quickly finds an electron, and they [[Annihilation|annihilate]] each other. The two resulting [[gamma ray]]s (γ) are detectable. The neutron can be detected by its capture on an appropriate nucleus, releasing a gamma ray. The coincidence of both events—positron annihilation and neutron capture—gives a unique signature of an antineutrino interaction.

In February&nbsp;1965, the first neutrino found in nature was identified by a group including Frederick Reines and [[Friedel Sellschop]].<ref>{{cite web |url=https://www.space.com/what-are-neutrinos |title=What are neutrinos? |date=2022-09-21 |access-date=2023-12-22 |website=Space.com |last=Cooper |first=Keith |archive-date=22 December 2023 |archive-url=https://web.archive.org/web/20231222154103/https://www.space.com/what-are-neutrinos |url-status=live }}</ref><ref>{{cite journal |last1=Reines |first1=F. |last2=Crouch |first2=M. F. |last3=Jenkins |first3=T. L. |last4=Kropp |first4=W. R. |last5=Gurr |first5=H. S. |last6=Smith |first6=G. R. |last7=Sellschop |first7=J. P. F. |last8=Meyer |first8=B. |title=Evidence for High-Energy Cosmic-Ray Neutrino Interactions |journal=Physical Review Letters |date=30 August 1965 |volume=15 |issue=9 |pages=429–433 |doi=10.1103/PhysRevLett.15.429 |bibcode=1965ICRC....2.1051R |url=https://adsabs.harvard.edu/full/1965ICRC....2.1051R |access-date=22 December 2023}}</ref> The experiment was performed in a specially prepared chamber at a depth of 3&nbsp;km in the [[East Rand Mine|East Rand ("ERPM") gold mine]] near [[Boksburg]], South Africa. A plaque in the main building commemorates the discovery. The experiments also implemented a primitive neutrino astronomy and looked at issues of neutrino physics and weak interactions.<ref>
{{cite journal
 |last1=Johnson |first1=C.D.
 |last2=Tegen |first2=Rudolph
 |title=The ''little neutral one'': An overview of the neutrino
 |date=January 1999
 |journal=[[South African Journal of Science]]
 |volume=95
 |number=95 |pages=13–20
 |hdl=10520/AJA00382353_7822
 |url=https://journals.co.za/doi/pdf/10.10520/AJA00382353_7822
}}
</ref>