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Final Answers
© 2000-2023   Gérard P. Michon, Ph.D.

Weak Nuclear Force
The only parity-violating interaction

 Coat-of-arms of 
 John von Neumann (1903-1957)
Young man, in mathematics,
you don't understand things.
 You just get used to them.

John von Neumann  (1903-1957)

Related articles:

Related Links (Outside this Site)

First Measurememt of Weak ForceMike McRae  (ScienceAlert, 2018-05-06)

Beta Radioactivity  by  Rod Nave  (Hyperphysics).

Wikipedia :   Weak interactions   |   Electroweal theory

Hunting for Neutrinos (40:38)  Vincenzo Cavasinni & Paola Catapano  (2007).
Directed by  Emanuele Angiuli  and produced, under the name  "Orione",  by  CERN,  Istituto Nazionale di Fisica Nucleare (INFN-Pisa),  Laboratori Nazionali Gran Sasso (LNGS), Laboratori Nazionali del Sud (LNS-Catania)  and the association for scientific culture  La Limonaia  (Pisa).

 
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Beta-Decay,  Weak Interactions  &  Neutrinos

 Wolfgang Pauli  
 1852-1908
(2018-05-27)  Conservation laws in beta-decay  (1930)
This is what led Pauli to postulate the existence of an elusive neutral particle of spin 1/2,  now called  neutrino.

" I have done a terrible thing:  I have postulated a particle that cannot be detected.."   Wolfgang Pauli  (Dec. 1930).

Pauli was definitely too harsh on himself.  The fact that  three  conserved quantity would otherwise be missing in beta-decay  (energy, linear momentum and angular momentum)  would now be considered a definite proof of something  otherwise  undetected.  Pauli had proposed to call the new particle  "neutron"  because it had no electrical charge but that name would soon be preempted by  James Chadwick (1891-1974; Nobel 1935)  for the massive nuclear particle he discovered in 1932,  which now stands.

The particle postulated by Pauli was given its final name of  neutrino  (Italian for "little neutron")  by  Enrico Fermi (1901-1954)  who first used the name in public at a meeting in Paris  (July 1932)  following a suggestion made jokingly in a friendly conversation with another Italian physicist  Edoardo Amaldi (1908-1989)  in the wake of Chadwick's aforementioned discovery of the  neutron.

 Come back later, we're
 still working on this one...

The Story of the Neutrino     Wikipedia :  Beta decay  |  Neutrino
 
The Elusive Neutrino and the Nature of the Cosmos (1:30:41)  World Science Festival  (2012-06-01).
Neutrinos:  Nature's Ghosts (4:56)  by  Don Lincoln   (Fermilab, 2013-06-18).
Neutrinos (11:29)  Sixty symbols   (2010-06-15).

 Enrico Fermi 
 1901-1954
(2018-06-06)  Fermi Theory of Beta-Decay   (1933).
Fermi coupling constant.  (No  intermediate bosons.)

GF / (h-bar c) 3   =   1.1663787(6)  GeV-2

 Come back later, we're
 still working on this one...

Fermi's interaction   |   Fermi coupling constant   |   Enrico Fermi (1901-1954)


(2018-06-06)  Direct Detection of Neutrinos
The  Cowan-Reines neutrino experiment  (1956).

In 1942,  Wang Ganchang (1907-1998)  had suggested that  reverse   beta capture  could provide an experimental way to detect the influx of antineutrinos from a nearby nuclear reactor,  through the reaction:

ne  +  p+     ®     n  +  e+

It would take another  14  years to actually make such a detection,  which earned the surviving experimenter (Reines) a belated Nobel prize in 1995.

In a  supernova,  a huge number of neutrinos are typically observed several hours before the explosion can be detected optically.  This was first noticed  (after the fact)  in the case of  SN1987A,  a naked-eye supernova from the  Large Magellanic Cloud  whose light first reached us on 1987-02-23.

Now,  a system of neutrino detectors is in place  (SNEWS)  to provide early-warning directional information to all observatories a few hours before the  the next nearby supernova  becomes visible...  We don't want to miss it!

Clyde Cowan (1979-1974)   |   Frederick Reines (1918-1998)   |   1995 Nobel Prize in Physics
 
How to detect a neutrino (9:32)  by  Don Lincoln   (Fermilab, 2019-05-28).
Subatomic Stories: The amazing neutrino (11:18)  by  Don Lincoln   (Fermilab, 2020-04-29).


(2018-05-28)  Wu experiment  shows Weak Force violates parity   (1956)
Tsung-Dao Lee (30)  Chen-Ning Yang (34)  and  Chien-Shiung Wu (44).

The  Wu experiment.

 Come back later, we're
 still working on this one...

Tsung-Dao Lee (1926-)   |   Chen-Ning Yang (1922-)   |   Chien-Shiung Wu (1912-1997)
 
Through the looking glass (9:17)  by  Don Lincoln   (Fermilab, 2017-05-10).


(2018-07-29)  Electron-neutrino  vs.  muon-neutrino   (Feinberg, 1958)
Experimental discovery by Lederman, Schwartz & Steinberger  (1962).

Lederman and Steinberger attended the Stanford meeting of the APS in December 1957,  where Feynman and Gell-Mann reported on their joint work

 Come back later, we're
 still working on this one...

Gerald Feinberg (1933-1992)
Leon M. Lederman (1922-2018)  |  Melvin Schwartz (1932-2006)  |  Jack Steinberger (1921-)  |  Nobel 1988
 
Dec. 1957 meeting of the APS at Stanford (1:55)  by  Murray Gell-Mann  (1998).
Muon and electron neutrinos (1:12)  by  Murray Gell-Mann  (1998).


(2018-06-04)  Flavor-Changing Weak Interactions
Emitting or absorbing a  W boson  changes the flavor of a particle.

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 still working on this one...

Quantum Chameleon (6:55)  by  Don Lincoln   (Fermilab, 2017-03-23).
 
Electroweak force (6:55)  by  Arvin Ash   (2020-09-26).


(2018-06-06)  Electroweak Theory
Quantum unification of electromagnetism and weak interactions.

As a student of Julian Schwinger (1918-1994; Nobel 1965Sheldon Glashow (b. 1932)  originally came up with the idea which eventually led to our current understanding of the weak force with three intermediate vector bosons  (massive bosons of spin 1)  besides the photon,  using Yang-Mills theory.  Two of opposite unit charge  (W- and W+)  and a neutral one  (Zo).  It wasn't yet clear at this point how this would account for the observed  strangeness-changing  properties of weak interactions.

In Paris,  in 1959,  Glashow talked about that to  Gell-Mann,  who reformulated the idea and reported on it at the Rochester conference of 1960.  The problem was then to generalize Yang-Mills theory beyond the SU(2) of isospin.  It took a young assistant professor of mathematics at Caltech  (Dick Bloch)    to point out to Gell-Mann,  in the Fall of 1960,  that simple Lie groups had already been classified before SU(3) appeared as the next logical choice for such a generalization,

 Come back later, we're
 still working on this one...

Shelly Glashow's idea and the road to  SU(3)  (4:104:01)  by  Murray Gell-Mann 
Why is the Weak Force weak?  (10:32)  by  Don Lincoln   (Fermilab, 2017-04-14).


(2018-08-03)  Solar Neutrinos  &  Neutrino Oscillations   (1957, 1998)
Proving that neutrino can't be massless.

Production of Solar Neutrinos :

Bruno Pontecorvo (1913-1993)  was the youngest of  Fermi's  Via Panisperna boys.

Willy Fowler (1911-1995; Nobel 1983) and John McCool at Caltech.

The  Standard solar model  John Bahcall.

The cross-section of a neutrino is a rapidly-increasing function of its energy.

The Homestake Experiment :

In 1948,  Ray Davis  was a  chemist  working for Brookhaven National Laboratory  on Long Island, NY.  He set up the  Homestake experiment  using 100,000 gallon tank of  perchlorethylene  (dry-cleaning fluid)  4580 ft underground in a  South Dakota gold mine. Over the course of several decades,  the experiment consistently detected about 1/3 of the neutrino flux predicted by the  Standard solar model.

 Come back later, we're
 still working on this one...

Herb Chen (1942-1987). Sudbury Neutrino Observatory (SNO).

Neutrino oscillations (1957)   |   Bruno Pontecorvo (1913-1993)
Homestake experiment   |   Ray Davis (1914-2006; Nobel 2002)   |   John Bahcall (1934-2005)
Interviews with Dr. Ray Davis (1:28, 2:53, 4:02, 2:20)  by  Wayne Paananen  (December 1990).
Observing solar neutrinos (2:35, 4:07, 1:55)  by  Hans Bethe  (Web of stories).
KamiokaNDE   |   Masatoshi Koshiba (1926-; Nobel 2002)
MSW effect  |  Stanislav Mikheyev (1940-2011)  |  Alexei Smirnov (1951-)  |  Lincoln Wolfenstein (1923-2015)
 
2015 Neutrino Nobel Prize  (8:01)  by  Brady Haran   (Sixty symbols, 2015-10-06).
Knowing Neutrinos (53:31, 23:19)  by  Art McDonald   (RI, 2016-07-04).
Neutrinos:  Nature's Identity Thieves (5:56)  by  Don Lincoln   (Fermilab, 2013-07-11).

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