[物理學求救]CP violation

唔明點解kaon decay會violate CP symmetry
long/short kaon同anti kaon pair唔match又有咩問題

淨係P violation就明
但係CP個情況就睇唔出個問題係邊

有冇物理學家可以解釋下

Kaon Long CP 係 -1
decay 做兩個 pion, CP 係 +1

其中一樣唔明係kaon long/short物理上係咩黎
數學上就可以寫做kaon anti-kaon嘅superposition
實際上係啲咩travel緊？
可唔可以解釋多啲

有冇人識

Kaon0/ anti-Kaon0 係 strong eigenstate。 因為 Kaon production 多數係thru strong interaction, 所以一般觀察到嘅 Kaon track 係係呢個 basis。
Kaon S /L 係 weak eigenstate, Kaon decay thru weak interaction, 所以要understand decay process就要project 返去呢個 basis。
你有無聽過過 Cabbibo angle ?

你可以睇左 neutrino oscillation 先, similar physics but easier to understand。

姐係kaon0 anti kaon0會好似neutrino咁互相oscillate
而decay做π反而係少數(當中有3π/2π)
kaon L/S就係oscillate緊嘅kaon0 ?

要視乎你係 observe 緊咩
K_L 同 K_S 係 mass eigenstate, 姐係 propagating Kaon , 你見到嘅 particle track。
K0 係 strong eigenstate , Kaon just produced from strong interaction will be in this state。
換言之你見到嘅 Kaon track 唔係 K0, 係 either KL or KS, which in turn is a mixture of K0 and antiK0

你可以想像 KL, KS 係 v1 v2 v3
K0 antiK0 係 ve vu vt

明白多左
順便問下
cp會violate係咪同中間啲粒子obey嘅symmetry group有關

ultimately it comes from the CP violating phase in mixing matrix (CKM matrix)

CKM matrix係咪可以好似普通S matrix咁derive出黎？
我想知多CP啲個原因多過點describe
anyway感謝個回答

無得 derive, 只可以 measure
Standard Model 嘅 basic parameter 。
There is no a priori reason for CP be a fundamental symmetry.

CKM matrix is conceptually very different from S matrix

睇多左依家明白
感謝