3. General Physics
3
Yuan CHAO
基本粒子基本粒子
在自然界，穩定存在的粒子：在自然界，穩定存在的粒子：
電子電子 ( β( β 粒子粒子 ) 1897 by Joseph John Thomson) 1897 by Joseph John Thomson
質子質子 1917 by Emest Rutherford1917 by Emest Rutherford
中子中子 1932 by James Chadwick1932 by James Chadwick
不穩定存在的「次級粒子」由宇宙射線中發現不穩定存在的「次級粒子」由宇宙射線中發現
最早實驗由最早實驗由 Victor Hess in 1912-1913 (Victor Hess in 1912-1913 ( 熱氣球熱氣球 ))
絕緣的驗電瓶逐漸放電絕緣的驗電瓶逐漸放電
隨實驗所在高度越高，放電越快隨實驗所在高度越高，放電越快
來自於外太空的來自於外太空的
「一級粒子」與「一級粒子」與
大氣層反應產生大氣層反應產生
加速器發明之前，加速器發明之前，
粒子物理的重要工具粒子物理的重要工具
7. General Physics
7
Yuan CHAO
八重道八重道 Eightfold WayEightfold Way
越來越多「基本粒子」被發現越來越多「基本粒子」被發現 ......
規則？規則？ Eightfold Way by Gell-Mann / Yuval Ne'emanEightfold Way by Gell-Mann / Yuval Ne'eman
11. General Physics
11
Yuan CHAO
基本粒子基本粒子
隨著加速器的發展，更多的粒子被發現隨著加速器的發展，更多的粒子被發現
詳細的資料可見詳細的資料可見 PDGPDG 手冊或網頁手冊或網頁 ::
http://pdglive.lbl.gov/http://pdglive.lbl.gov/
特別的屬性特別的屬性 ccττ
粒子偵測器中可見的「長壽命」粒子：粒子偵測器中可見的「長壽命」粒子：
ee±±
,, μμ±±
,, γγ,, ππ±±
,K,K±±
, K, KLL
, n, p, n, p±±
不同的粒子有不同的「靜止質量」不同的粒子有不同的「靜止質量」
Resonance / rest mass is like the finger print of particlesResonance / rest mass is like the finger print of particles
類比於類比於光譜分析光譜分析的概念的概念
12. General Physics
12
Yuan CHAO
共振態共振態
衰變粒子重建衰變粒子重建
短壽命粒子的生命期小於短壽命粒子的生命期小於 1010-23-23
secsec
當接近光速運動時 → 衰變軌跡小於當接近光速運動時 → 衰變軌跡小於 1010-15-15
mm
實驗觀測碰撞截面實驗觀測碰撞截面 cross-sectioncross-section σσ 與不變質量與不變質量 invariantinvariant
mass Mmass M,, 的分佈，共振態以鐘形分佈出現的分佈，共振態以鐘形分佈出現 bell-shapedbell-shaped
E = m cE = m c22
自然單位自然單位 :: c =c = ħħ = 1= 1
16. General Physics
16
Yuan CHAO
四大問題四大問題
LHC was built for the followingLHC was built for the following
purposes:purposes:
質量的來源質量的來源
To find the origin of mass...To find the origin of mass...
thethe HiggsHiggs boson.boson.
暗物質與暗能量暗物質與暗能量
Looking for the unification..Looking for the unification..
Super-symmetrySuper-symmetry as well asas well as
other candidates ofother candidates of Dark MaterDark Mater
&& Dark energyDark energy
反物質的消失反物質的消失
Investigate the mystery ofInvestigate the mystery of
anti-matteranti-matter disappearancedisappearance
宇宙初期狀態宇宙初期狀態
Physics at the early stage of thePhysics at the early stage of the
universe:universe: Heavy Ion CollisionsHeavy Ion Collisions
andand Quark-Gluon PlasmaQuark-Gluon Plasma
Courtesy of Center for European Nuclear Research (CERN), Geneva,
Switzerland.
18. 18
Yuan CHAO
Big News on 2012/07/04Big News on 2012/07/04
Discovery of a New BosonDiscovery of a New Boson
with Masswith Mass ~125 GeV/c~125 GeV/c22
CERN-HI-1207136_92
24. 25
Yuan CHAO
關於對稱性關於對稱性 SymmetrySymmetry
People think the universe is symmetric?People think the universe is symmetric?
Parity violationParity violation introduced by T.D. Lee (introduced by T.D. Lee ( 李政道李政道 ) and C.N.) and C.N.
Yang (Yang ( 楊振寧楊振寧 ) in 1956.) in 1956.
Parity violationParity violation seen in aseen in a ββ decaydecay by C.S. Wu (by C.S. Wu ( 吳健雄吳健雄 ) in) in
1957. Nobel prize for Lee & Yang.1957. Nobel prize for Lee & Yang.
CP violationCP violation discovered in Kaon system in 1964.discovered in Kaon system in 1964.
M. Kobayashi and T. Maskawa introducedM. Kobayashi and T. Maskawa introduced CP violationCP violation inin
thethe Standard ModelStandard Model in 1973.in 1973.
Sanda and Carter pointed out the possibility ofSanda and Carter pointed out the possibility of CPCP
violationviolation in the B meson system in 1980.in the B meson system in 1980.
25. 26
Yuan CHAO
About SymmetryAbout Symmetry
KTeV experiment at FNAL established the directKTeV experiment at FNAL established the direct CPCP
violationviolation in Kaon system and confirmed by NA48 atin Kaon system and confirmed by NA48 at
CERN in 1999.CERN in 1999.
BelleBelle andand BaBarBaBar observed indirectobserved indirect CP violationCP violation B mesonB meson
system in 2002.system in 2002.
Belle observed the directBelle observed the direct CP violationCP violation inin B →B → ππππ but notbut not
confirmed by BaBar in 2004confirmed by BaBar in 2004
Belle and BaBar present the directBelle and BaBar present the direct CP violationCP violation inin B →B →
KKππ in 2004.in 2004.
M. KobayashiM. Kobayashi 小林誠小林誠 and T. Maskawaand T. Maskawa 益川敏英益川敏英 shareshare
thethe Nobel Prize in 2008Nobel Prize in 2008
with Y. Nambuwith Y. Nambu 南部陽一郎南部陽一郎 ..
CPCP 破壞所能夠解釋的正反粒子破壞所能夠解釋的正反粒子
不對稱性，仍與天文觀測所得有不對稱性，仍與天文觀測所得有
相當大的差距相當大的差距 ~O(10~O(1099
))
