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===About Mesons===
: '''Mesons''' have a very short [[Half Life|half life]], [[Radioactive Decay|decaying]] via the [[Weak Nuclear Interaction|weak nuclear interaction]] or though the [[quark]]-[[antiquark]] pair [[annihilation|annihilating]] one another.
: '''Mesons''' consisting of the [[quark]]s; [[up-quark]], [[down-quark]] and [[strange-quark]] are divided into two main categories; [[π-meson]]s and [[k-mesonsmeson]]s.
: '''[[K-meson]]s''' have a [[strangeness]] of +1 or -1. However, [[π-meson]]s do not carry [[strangeness]].
: '''Mesons''' are affected by the:
===Determining Meson Composition===
''NB: You do not need to memorise the exact composition of a given '''meson'''. However, you should be able to determine the a possible [[quark]] composition given the [[Electrical Charge|charge]] and [[strangeness]] of the [[meson]] and by remembering the properties of the [[up-quark]], [[down-quark]] and [[strange-quark]].''
: '''Mesons''' can be shown in the following diagram:
{| border="1" style="border-collapse:collapse"
====Examples====
{| classborder="wikitable1" style="border-collapse:collapse"
|+ This table is for referencing the properties of the [[quark]]s.
| style="height:20px; width:200px; text-align:center;"|'''[[Quark]]'''
| style="height:20px; width:200px; text-align:center;"|[[Electrical Charge|'''Charge''']]/[[Elementary Charge|e]]
| style="height:20px; width:200px; text-align:center;"|'''[[Strangeness]]'''
|-
| style="height:20px; width:200px; text-align:center;"|
[[Up-quark]](<math>u</math>)
| style="height:20px; width:200px; text-align:center;"|<math>q=+\frac{2}{3}</math>
|-
| style="height:20px; width:200px; text-align:center;"|
[[Antiup-quark]](<math>\bar{u}</math>)
| style="height:20px; width:200px; text-align:center;"|<math>q=-\frac{2}{3}</math>
|-
| style="height:20px; width:200px; text-align:center;"|
[[Down-quark]](<math>d</math>)
| style="height:20px; width:200px; text-align:center;"|<math>q=-\frac{1}{3}</math>
|-
| style="height:20px; width:200px; text-align:center;"|
[[Antidown-quark]](<math>\bar{d}</math>)
| style="height:20px; width:200px; text-align:center;"|<math>q=+\frac{1}{3}</math>
|-
| style="height:20px; width:200px; text-align:center;"|
[[Strange-quark]](<math>s</math>)
| style="height:20px; width:200px; text-align:center;"|<math>q=-\frac{1}{3}</math>
|-
| style="height:20px; width:200px; text-align:center;"|
[[Antistrange-quark]](<math>\bar{s}</math>)
| style="height:20px; width:200px; text-align:center;"|<math>q=+\frac{1}{3}</math>
| style="height:20px; width:200px; text-align:center;"|<math>S=+1</math>
|}
{| class="wikitable"
|-
| style="height:20px; width:300px; text-align:left;" |
'''[[Strangeness]]'''
π<sup>+</sup> has a [[strangeness]] of 0, therefore it contains no [[strange-quark]] or [[antistrange-quark]].
'''[[Electrical Charge|Charge]]''' π<sup>+</sup> has a [[Positive Charge|positive charge]]. This can be achieved with one [[Electrical Charge|charge]] of <math>+\frac{2}{3}</math> [[Elementary Charge|e]] (an [[up-quark]]) and <math>+\frac{1}{3}</math> [[Elementary Charge|e]] (an [[antidown-quark]]). Since <math>+1 = +\frac{2}{3} + \frac{1}{3}</math>
Therefore <math>π^+ = u + \bar{d}</math>
An up-antidown pair.
| style="height:20px; width:300px; text-align:left;" |
'''[[Strangeness]]'''
K<sup>-</sup> has a [[strangeness]] of -1, therefore it contains a [[strange-quark]].
'''[[Electrical Charge|Charge]]''' <math>-1 = -\frac{1}{3} + x</math> K<sup>-</sup> has a [[Negative Charge|negative charge]]. This can be achieved with one its [[strange-quark]] with an a [[Electrical Charge|charge]] of [[<math>-\frac{1}{3}</math> [[Elementary Charge|e]] and another [[Electrical Charge|charge]] of <math>-\frac{2}{3}</math> [[Elementary Charge|e]] (an [[antiup-quark]]). Since <math>-1 = -\frac{1}{3} + -\frac{2}{3}</math>
Therefore <math>K^- = S s + \bar{u}</math>
A strange-antiup pair.
|}