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Natural Science
Observation Generalising andmaking physical laws
Extracting moreabstract concept
Postulatingand
predictingphenomena
Observation
f = Gm1 m2
r2
gg
Geometrical Symmetries
Translation Rotation Reflection(parity)
RRRRRRRRRR
RR RRRR
RRR
RR
R
continuous continuous discrete
Goal of Elementary Particle Physics
To look for
1) the ultimate building blocks of the world
2) forces between them
3) underlying dynamics
Examples
Atomic System
Building Force Underlyingblocks dynamics
electron and electromagnetic Quantumnucleus interaction Mechanics
(relativistic)
Solar System
Building Force Underlyingblocks dynamics
sun and planets gravitation Newton’s lawsof motion
Elementary Particle System
Building Force Underlyingblocks dynamics
quarks and electromagnetic Quantumleptons (photon: ) Field
+ weak Theoryanti-quarks and (W, Z0)
anti-leptons strong(gluon: g)
The Standard Model
q
q
e
e
W
q
q
e
g
q
q
q
q
Properties of building blocks, forces and underlying dynamics
can be described by rotation and/or translation symmetries
in four-dimensional real space (t, x, y, z)
orsome “internal” space
What about discrete symmetries?
Parity: (x, y, z) (x, y, z)we saw already
Charge conjugation: particle antiparticleTime reversal: t t
two more to come
No quantum field theory without CPT symmetry
particle world antiparticle world
antineutrinoneutrino
Right-handedLeft-handed
connected byCP
transformation
CP Violation
We know two examples which showsmatter world anti-matter world.
CP symmetry is violated !!
Evolution of Universe
big bang
matter
anti-matter
amount of matter = amount of anti-matter
our universeonly with matter
CP violation
CPLEAR Experiment (1999)
neutral kaondecay time distribution
anti-neutral kaondecay time distribution
CP violation
Problem!!
CP violation inthe kaon decays
canbe explained by
the Standard Model.
CP violation inthe universe
cannot be explained by
the Standard Model.
LHCb experiment will look for CP violation beyond the Standard Model in the particle world
using B-mesons.
Mechanism of CP Violation
W
q
q
complex coupling constant
Standard Model
X
q
q
complex coupling constant
New Physics
CP transformation containscomplex conjugation:
eiH t eiH*t
i.e. H* H CP violation
At LHC
p7 TeV= cal
1g of those p’s = 20 daysof US energy consumption
p7 TeV
LHCb detector
14 TeV mini bang
~100 times more B mesons then before
LHCbYoke
RICH-1
Vertex
Shieldingplate
TrackerCalorimeters
MounRICH-2
Coil
The LHCb Experiment
Netherlands
Brazil
France
Germany
Italy PRC Romania Spain
Switzerland
Ukraine
UK
USA
Poland Russia
Finland
Primary Goal of LHCb
To understand better the origin of CP violation.
Possibly discovering new physics beyond the Standard Model.
FAQ
Why do we do/teach particle physics?
- applied research will achieve “state of art”.- basic research opens new horizon.
Why do we do basic research?
- understanding the most fundamental nature of material isone of the most important cultural activities.
- elementary particles are one of the basic concepts of modern physics which should be known by everybody.
No Maxwell, no radio nor TV.No Röntgen, no X ray picture.No Quantum Mechanics, no modern electronics
Everybody knows that the earth is round!