Type of subatomic particle
Bosons form one of the two fundamental classes of
subatomic particle
, the other being
fermions
. All subatomic particles must be one or the other. A composite particle (
hadron
) may fall into either class depending on its composition
In
particle physics
, a
boson
(
[1]
[2]
) is a
subatomic particle
whose
spin quantum number
has an integer value (0, 1, 2, ...). Bosons form one of the two fundamental classes of subatomic particle, the other being
fermions
, which have odd half-integer spin (
1
⁄
2
,
3
⁄
2
,
5
⁄
2
, ...). Every observed subatomic particle is either a boson or a fermion.
Paul Dirac
coined the name
boson
to commemorate the contribution of
Satyendra Nath Bose
, an
Indian
physicist.
Some bosons are
elementary particles
occupying a special role in particle physics, distinct from the role of fermions (which are sometimes described as the constituents of "ordinary matter"). Certain elementary bosons (e.g.
gluons
) act as
force carriers
, which give rise to forces between other particles, while one (the
Higgs boson
) contributes to the phenomenon of
mass
. Other bosons, such as
mesons
, are composite particles made up of smaller constituents.
Outside the realm of particle physics, multiple identical composite bosons (in this context sometimes known as '
bose particles
') behave at high densities or low temperatures in a characteristic manner described by
Bose?Einstein statistics
: for example a gas of
helium-4
atoms becomes a
superfluid
at temperatures close to absolute zero. Similarly,
superconductivity
arises because some
quasiparticles
, such as
Cooper pairs
, behave in the same way.
Name
[
edit
]
The name
boson
was coined by
Paul Dirac
[3]
[4]
to commemorate the contribution of
Satyendra Nath Bose
, an
Indian
physicist. When Bose was a reader (later professor) at the
University of Dhaka
,
Bengal
(now in
Bangladesh
),
[5]
[6]
he and
Albert Einstein
developed the theory characterising such particles, now known as
Bose?Einstein statistics
and
Bose?Einstein condensate
.
[7]
Elementary bosons
[
edit
]
All observed
elementary particles
are either bosons (with integer spin) or
fermions
(with odd half-integer spin).
[8]
Whereas the elementary particles that make up ordinary matter (
leptons
and
quarks
) are fermions, elementary bosons occupy a special role in particle physics. They act either as
force carriers
which give rise to forces between other particles, or in one case give rise to the phenomenon of
mass
.
According to the
Standard Model of Particle Physics
there are five elementary bosons:
- A
second order tensor boson
(spin = 2) called the
graviton
(G) has been hypothesised as the force carrier for
gravity
, but so far all attempts to incorporate gravity into the Standard Model have failed.
[a]
Composite bosons
[
edit
]
Composite particles (such as
hadrons
,
nuclei
, and
atoms
) can be bosons or fermions depending on their constituents. Since bosons have integer
spin
and fermions odd half-integer spin, any composite particle made up of an even number of fermions is a boson.
Composite bosons include:
As
quantum particles
, the behaviour of multiple indistinguishable bosons at high densities is described by
Bose?Einstein statistics
. One characteristic which becomes important in
superfluidity
and other applications of
Bose?Einstein condensates
is that there is no restriction on the number of bosons that may occupy the same
quantum state
. As a consequence, when for example a gas of
helium-4
atoms is cooled to temperatures very close to
absolute zero
and the
kinetic energy
of the particles becomes negligible, it condenses into a low-energy state and becomes a
superfluid
.
Quasiparticles
[
edit
]
Certain
quasiparticles
are observed to behave as bosons and to follow
Bose?Einstein statistics
, including
Cooper pairs
,
plasmons
and
phonons
.
[10]
: 130
See also
[
edit
]
- Anyon
? Type of two-dimensional quasiparticle
- Bose gas
? State of matter of many bosons
- Parastatistics
? Notion in statistical mechanics
Explanatory notes
[
edit
]
- ^
Despite being the carrier of the gravitational force which interacts with mass, most attempts at
quantum gravity
have expected the graviton to have no mass, just like the photon has no electric charge, and the
W and Z bosons
have no
"flavour"
.
- ^
Even-mass-number nuclides
comprise
153
/
254
= 60% of all stable nuclides. They are bosons, i.e. they have integer spin, and almost all of them (148 of the 153) are even-proton / even-neutron (EE) nuclides. The EE nuclides necessarily have spin 0 because of pairing. The remaining 5 stable bosonic nuclides are odd-proton / odd-neutron (OO) stable nuclides (see
Even and odd atomic nuclei § Odd proton, odd neutron
). The five odd?odd bosonic nuclides are:
Each of the five has integer, nonzero spin.
References
[
edit
]
- ^
"boson"
.
Lexico
UK English Dictionary
.
Oxford University Press
. Archived from
the original
on 9 July 2021.
- ^
Wells, John C. (1990).
Longman pronunciation dictionary
. Harlow, England: Longman.
ISBN
978-0582053830
.
entry "Boson"
- ^
Notes on Dirac's lecture
Developments in Atomic Theory
at Le Palais de la Decouverte, 6 December 1945
. UKNATARCHI Dirac Papers. BW83/2/257889.
- ^
Farmelo, Graham (25 August 2009).
The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom
. Basic Books. p. 331.
ISBN
9780465019922
.
- ^
Daigle, Katy (10 July 2012).
"India: Enough about Higgs, let's discuss the boson"
.
Associated Press
. Retrieved
10 July
2012
.
- ^
Bal, Hartosh Singh (19 September 2012).
"The Bose in the Boson"
. Latitude (blog).
The New York Times
. Archived from
the original
on 22 September 2012
. Retrieved
21 September
2012
.
- ^
"Higgs boson: The poetry of subatomic particles"
.
BBC News
. 4 July 2012
. Retrieved
6 July
2012
.
- ^
Carroll, Sean (2007).
Guidebook
. Dark Matter, Dark Energy: The dark side of the universe. The Teaching Company. Part 2, p. 43.
ISBN
978-1598033502
.
... boson: A force-carrying particle, as opposed to a matter particle (fermion). Bosons can be piled on top of each other without limit. Examples are photons, gluons, gravitons, weak bosons, and the Higgs boson. The spin of a boson is always an integer: 0, 1, 2, and so on ...
- ^
Qaim, Syed M.; Spahn, Ingo; Scholten, Bernhard; Neumaier, Bernd (8 June 2016).
"Uses of alpha particles, especially in nuclear reaction studies and medical radionuclide production"
.
Radiochimica Acta
.
104
(9): 601.
doi
:
10.1515/ract-2015-2566
.
S2CID
56100709
. Retrieved
22 May
2021
.
- ^
Poole, Charles P. Jr. (11 March 2004).
Encyclopedic Dictionary of Condensed Matter Physics
. Academic Press.
ISBN
978-0-08-054523-3
.