bottom quark (99.8%) strange quark (0.17%) down quark (0.007%)
Electric charge
+ 2 /3e
Color charge
yes
Spin
1 /2ħ
Topness
1
Weak isospin
LH: + 1 /2, RH: 0
Weak hypercharge
LH: +1 /3, RH: +4/3
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The top quark, sometimes also referred to as the truth quark, (symbol: t) is the most massive of all observed elementary particles. It derives its mass from its coupling to the Higgs Boson. This coupling is very close to unity; in the Standard Model of particle physics, it is the largest (strongest) coupling at the scale of the weak interactions and above. The top quark was discovered in 1995 by the CDF[2] and DØ[3] experiments at Fermilab.
Like all other quarks, the top quark is a fermion with spin 1 /2 and participates in all four fundamental interactions: gravitation, electromagnetism, weak interactions, and strong interactions. It has an electric charge of + 2 /3e. It has a mass of 172.76±0.3 GeV/c2,[1] which is close to the rhenium atom mass.[4] The antiparticle of the top quark is the top antiquark (symbol: t, sometimes called antitop quark or simply antitop), which differs from it only in that some of its properties have equal magnitude but opposite sign.
The top quark interacts with gluons of the strong interaction and is typically produced in hadron colliders via this interaction. However, once produced, the top (or antitop) can decay only through the weak force. It decays to a W boson and either a bottom quark (most frequently), a strange quark, or, on the rarest of occasions, a down quark.[a]
The Standard Model determines the top quark's mean lifetime to be roughly 5×10−25 s.[5] This is about a twentieth of the timescale for strong interactions,[b] and therefore it does not form hadrons, giving physicists a unique opportunity to study a "bare" quark (all other quarks hadronize, meaning that they combine with other quarks to form hadrons and can only be observed as such).
Because the top quark is so massive, its properties allowed indirect determination of the mass of the Higgs boson (see § Mass and coupling to the Higgs boson below). As such, the top quark's properties are extensively studied as a means to discriminate between competing theories of new physics beyond the Standard Model. The top quark is the only quark that has been directly observed due to its decay time being shorter than the hadronization time.[b][6]
^ abCite error: The named reference PDG2020 was invoked but never defined (see the help page).
^Cite error: The named reference CDF-1995 was invoked but never defined (see the help page).
^Cite error: The named reference D0-1995 was invoked but never defined (see the help page).
^Cite error: The named reference Hypertextbook was invoked but never defined (see the help page).
^Cite error: The named reference Quadt was invoked but never defined (see the help page).
^Aubert, Jean-Jacques; Gastmans, Raymond; Gérard, Jean-Marc (6 December 2012). Particle Physics: Ideas and recent developments. Springer, Dordrecht. p. 69. ISBN 978-0-7923-6436-8. Retrieved 11 June 2020.
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The topquark, sometimes also referred to as the truth quark, (symbol: t) is the most massive of all observed elementary particles. It derives its mass...
flavors, of quarks: up, down, charm, strange, top, and bottom. Up and down quarks have the lowest masses of all quarks. The heavier quarks rapidly change...
bottom quark, beauty quark, or b quark, is an elementary particle of the third generation. It is a heavy quark with a charge of −1/3 e. All quarks are described...
In particle physics, the topquark condensate theory (or top condensation) is an alternative to the Standard Model fundamental Higgs field, where the...
ordered set Top (mathematical logic), written top or ⊤, a data type containing all others Top, down tack, or Tee (symbol), the symbol ⊤ Topquark, the third-generation...
It, along with the down quark, forms the neutrons (one up quark, two down quarks) and protons (two up quarks, one down quark) of atomic nuclei. It is...
The strange quark or s quark (from its symbol, s) is the third lightest of all quarks, a type of elementary particle. Strange quarks are found in subatomic...
B′ (bottomness), T (topness), u (up quark), d (down quark), s (strange quark), c (charm quark), b (bottom quark), t (topquark), as well as other subatomic...
In particle physics, the quark model is a classification scheme for hadrons in terms of their valence quarks—the quarks and antiquarks that give rise to...
a top–antitop quark pair. However, such a decay would only be possible if the Higgs were heavier than ~346 GeV/c2, twice the mass of the topquark. For...
down quark (symbol: d) is a type of elementary particle, and a major constituent of matter. The down quark is the second-lightest of all quarks, and combines...
The charm quark, charmed quark, or c quark is an elementary particle found in composite subatomic particles called hadrons such as the J/psi meson and...
as the (light) η defined, but are made of charm quarks and bottom quarks respectively. The topquark is too heavy to form a similar meson, due to its...
electron-positron collider would be able to provide the precise measurements of the topquark needed for such calculations. Chaotic inflation theory suggests that the...
momentum), P (parity), u (up quark), d (down quark), s (strange quark), c (charm quark), t (topquark), b (bottom quark), Q (electric charge), S (strangeness)...
process of the formation of hadrons out of quarks and gluons. There are two main branches of hadronization: quark-gluon plasma (QGP) transformation and colour...
down quarks. Omega baryons containing topquarks are not expected to be observed. This is because the Standard Model predicts the mean lifetime of top quarks...
of three quarks; or a meson, composed of two quarks), or an elementary particle, which is not composed of other particles (for example, quarks; or electrons...
known quark mass is of the topquark ( t ) at 172.7 GeV/c2 or 172700 MeV/c2, estimated using the on-shell scheme. Estimates of the values of quark masses...
mid-1970s upon experimental confirmation of the existence of quarks. Since then, proof of the topquark (1995), the tau neutrino (2000), and the Higgs boson (2012)...
odd number of valence quarks, conventionally three. Baryons belong to the hadron family of particles; hadrons are composed of quarks. Baryons are also classified...
existence of the bottom quark solidified physicists' conviction that the topquark existed. The topquark was the last of the quarks to be observed, mostly...
a topquark and one additional subatomic particle. The second subatomic particle can be either an up quark ( T0 ), down quark ( T+ ), strange quark (...
of the topquark as predicted by supersymmetry (SUSY). It is a sfermion, which means it is a spin-0 boson (scalar boson). While the topquark is the heaviest...
(bottomonium, b b ). Because of the high mass of the topquark, toponium (θ meson) does not exist, since the topquark decays through the electroweak interaction...
the time was that the topquark mass would lie in a range of 15 to 26 GeV. The quasi-infrared fixed point emerged in topquark condensation theories of...
s) or charm quark ( B+ c). The combination of a bottom antiquark and a topquark is not thought to be possible because of the topquark's short lifetime...
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