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

Nature

Concept of Symmetry - regular pattern - symmetry - … Recognition Nature Observation

Creating arts - regular pattern - symmetry - … Concept Realisation

Natural Science Observation Generalising and making physical laws Extracting more abstract concept Postulating and predicting phenomena Observation f = G m1 m2m1 m2 r2r2 gggg

Other examples of symmetry

and Islamic beauties

Too symmetric is “unnatural”.

Some asymmetry makes… more dynamic

more beautiful

if not too much …?

Geometrical Symmetries Translation Rotation Reflection (parity) R R R R R R R R R R R R R R R R R R R R R R 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 BuildingForceUnderlying blocksdynamics electron andelectromagneticQuantum nucleusinteractionMechanics (relativistic) Solar System BuildingForceUnderlying blocksdynamics sun and planetsgravitationNewton’s laws of motion

Elementary Particle System BuildingForceUnderlying blocksdynamics quarks andelectromagneticQuantum leptons (photon:  ) Field +weakTheory anti-quarks and (W , Z 0 ) anti-leptonsstrong (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) or some “internal” space

What about discrete symmetries? Parity:(x, y, z)  (  x,  y,  z) we saw already Charge conjugation: particle  antiparticle Time reversal:t   t two more to come No quantum field theory without CPT symmetry

particle worldantiparticle world antineutrino neutrino Right-handed Left-handed connected by CP transformation

CP Violation We know two examples which shows matter world  anti-matter world. CP symmetry is violated !!

Evolution of Universe big bang matter anti-matter amount of matter = amount of anti-matter our universe only with matter CP violation

Weak decay of neutral K mesons KK  Decay Time

CPLEAR Experiment (1999) neutral kaon decay time distribution anti-neutral kaon decay time distribution CP violation 

Problem!! CP violation in the kaon decays can be explained by the Standard Model. CP violation in the 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 contains complex conjugation: e  iH t  e iH*t i.e. H*  H  CP violation

At LHC p 7 TeV=   cal 1g of those p’s = 20 days of US energy consumption p 7 TeV LHCb detector 14 TeV mini bang ~100 times more B mesons then before

CERN and LHC

CERN

Users

LHCb Yoke RICH-1 Vertex Shielding plate Tracker Calorimeters MounRICH-2 Coil The LHCb Experiment Netherlands Brazil France Germany Italy PRCRomania Spain Switzerland Ukraine UK USA Poland Russia Finland

An Event LHCb event seen 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 is one 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 international collaboration with a given time scale and still to remain creative. Why do we do experimental particle physics? We are all curious to know how we are here!