Symmetry and Its Violation -unifying concept of universe- Tatsuya Nakada Lausanne, 8 February 2000.

Symmetry and Its Violation-unifying concept of universe-

Tatsuya Nakada

Lausanne, 8 February 2000

Nature

Concept of Symmetry

- regular pattern- symmetry- …

RecognitionNature Observation

Creating arts

- regular pattern- symmetry- …

Concept Realisation

Natural Science

Observation Generalising andmaking physical laws

Extracting moreabstract concept

Postulatingand

predictingphenomena

Observation

f = Gm1 m2

r2

gg

Other examples of symmetry

and Islam

ic beau

ties

Too symmetric is “unnatural”.

Some asymmetry makes… more dynamic

more beautiful

if not too much…?

Geometrical Symmetries

Translation Rotation Reflection(parity)

RRRRRRRRRR

RR RRRR

RRR

RR

R

continuous continuous discrete

Spontaneous Breakdown of Rotational Symmetry

before dinner once dinner starts

Violation of L-R Symmetry

World

10%90%

Mirror World

90%10%

World Mirror World(parity violation)

Even more with DNA

L-R symmetry is fully violated.

World

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

Weak decay of neutral K mesons

K Decay Time

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

CERN and LHC

CERN

Users

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

An EventLHCb eventseen by the vertex detector(Lausanne participation)

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!

- experiments demands state of art technology: spin-off.

- students learn how to work in an internationalcollaboration with a given time scale andstill to remain creative.

Why do we do experimental particle physics?

We are all curious to knowhow we are here!