Difference between revisions of "Quark"
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===About Quarks=== | ===About Quarks=== | ||
+ | : The '''quark''' is denoted with a lower case '''q'''. | ||
: '''Quarks''' are believed to be [[Fundamental Particle|fundamental particles]] but they have never been observed on their own. | : '''Quarks''' are believed to be [[Fundamental Particle|fundamental particles]] but they have never been observed on their own. | ||
: '''Quarks''' always exist as part of [[hadron]] including a [[baryon]], which is a triplet of [[quark]]s or a [[meson]] which is a [[quark]]-[[antiquark]] pair. | : '''Quarks''' always exist as part of [[hadron]] including a [[baryon]], which is a triplet of [[quark]]s or a [[meson]] which is a [[quark]]-[[antiquark]] pair. | ||
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:*[[Down-quark]] (d) - With a [[Electrical Charge|charge]] of <math>-\frac{1}{3}</math>[[Elementary Charge|e]], two of which are found in a [[neutron]] and one of which is found in a [[proton]]. | :*[[Down-quark]] (d) - With a [[Electrical Charge|charge]] of <math>-\frac{1}{3}</math>[[Elementary Charge|e]], two of which are found in a [[neutron]] and one of which is found in a [[proton]]. | ||
:*[[Strange-quark]] (s) - With a [[Electrical Charge|charge]] of <math>-\frac{1}{3}</math>[[Elementary Charge|e]] which [[Radioactive Decay|decays]] quickly via the [[Weak Nuclear Interaction|weak interaction]] into a [[down-quark]]. | :*[[Strange-quark]] (s) - With a [[Electrical Charge|charge]] of <math>-\frac{1}{3}</math>[[Elementary Charge|e]] which [[Radioactive Decay|decays]] quickly via the [[Weak Nuclear Interaction|weak interaction]] into a [[down-quark]]. | ||
+ | (The following are not on all A-level syllabi) | ||
:*[[Top-quark]] (t) - With a [[Electrical Charge|charge]] of <math>+\frac{2}{3}</math>[[Elementary Charge|e]] which [[Radioactive Decay|decays]] quickly via the [[Weak Nuclear Interaction|weak interaction]]. | :*[[Top-quark]] (t) - With a [[Electrical Charge|charge]] of <math>+\frac{2}{3}</math>[[Elementary Charge|e]] which [[Radioactive Decay|decays]] quickly via the [[Weak Nuclear Interaction|weak interaction]]. | ||
:*[[Bottom-quark]] (b) - With a [[Electrical Charge|charge]] of <math>-\frac{1}{3}</math>[[Elementary Charge|e]] which [[Radioactive Decay|decays]] quickly via the [[Weak Nuclear Interaction|weak interaction]]. | :*[[Bottom-quark]] (b) - With a [[Electrical Charge|charge]] of <math>-\frac{1}{3}</math>[[Elementary Charge|e]] which [[Radioactive Decay|decays]] quickly via the [[Weak Nuclear Interaction|weak interaction]]. |
Latest revision as of 09:53, 19 May 2024
Key Stage 5
Meaning
Quarks (q) are a type of fermion and are the constituent parts of hadrons.
About Quarks
- The quark is denoted with a lower case q.
- Quarks are believed to be fundamental particles but they have never been observed on their own.
- Quarks always exist as part of hadron including a baryon, which is a triplet of quarks or a meson which is a quark-antiquark pair.
- There are 6 types of quark including:
- Up-quark (u) - With a charge of \(+\frac{2}{3}\)e, two of which are found in proton and one of which is found in a neutron.
- Down-quark (d) - With a charge of \(-\frac{1}{3}\)e, two of which are found in a neutron and one of which is found in a proton.
- Strange-quark (s) - With a charge of \(-\frac{1}{3}\)e which decays quickly via the weak interaction into a down-quark.
(The following are not on all A-level syllabi)
- Top-quark (t) - With a charge of \(+\frac{2}{3}\)e which decays quickly via the weak interaction.
- Bottom-quark (b) - With a charge of \(-\frac{1}{3}\)e which decays quickly via the weak interaction.
- Charm-quark (c) - With a charge of \(+\frac{2}{3}\)e which decays quickly via the weak interaction.
Conserved Quantities
Quark | Charge/e | Strangeness | Baryon Number | Lepton Number |
\(Q=+\frac{2}{3}\) | \(S=0\) | \(B=+\frac{1}{3}\) | \(L=0\) | |
\(Q=-\frac{1}{3}\) | \(S=0\) | \(B=+\frac{1}{3}\) | \(L=0\) | |
\(Q=-\frac{1}{3}\) | \(S=-1\) | \(B=+\frac{1}{3}\) | \(L=0\) | |
\(Q=+\frac{2}{3}\) | \(S=0\) | \(B=+\frac{1}{3}\) | \(L=0\) | |
\(Q=-\frac{1}{3}\) | \(S=0\) | \(B=+\frac{1}{3}\) | \(L=0\) | |
\(Q=+\frac{2}{3}\) | \(S=0\) | \(B=+\frac{1}{3}\) | \(L=0\) |
Antiquark | Charge/e | Strangeness | Baryon Number | Lepton Number |
\(Q=-\frac{2}{3}\) | \(S=0\) | \(B=-\frac{1}{3}\) | \(L=0\) | |
\(Q=+\frac{1}{3}\) | \(S=0\) | \(B=-\frac{1}{3}\) | \(L=0\) | |
\(Q=+\frac{1}{3}\) | \(S=+1\) | \(B=-\frac{1}{3}\) | \(L=0\) | |
\(Q=-\frac{2}{3}\) | \(S=0\) | \(B=-\frac{1}{3}\) | \(L=0\) | |
\(Q=+\frac{1}{3}\) | \(S=0\) | \(B=-\frac{1}{3}\) | \(L=0\) | |
\(Q=-\frac{2}{3}\) | \(S=0\) | \(B=-\frac{1}{3}\) | \(L=0\) |