SubAtomic Physics &

Astrophysics

Intimate Connexionbetween Very Large

and Very Small

Plan of Talk

• Research Interests at Toronto

• Standard Model of Particle Physics

• Puzzles

• Profound connexion between understanding of microstructure and macrostructure of universe.

• Solutions???? • Experiments

Interest Groups @ UofT

• Experimental Particle Physics Origin of Mass, Structure of Proton ….

Large Projects: ATLAS, CDF, ZEUSBailey, Martin, Orr, Sinervo, Trischuk

6 Post Docs12 grad students

• Experimental CosmologyGeometry of Space-TimeLarge Project: BoomerangNetterfield - just starting !

1 grad student

• Theoretical Particle PhysicsOrigin of Mass, Structure of Hadronic MatterHoldom, Luke, O’Donnell

3 Post Docs4 grad students

• Large Program In Astrophysics Galaxy Formation

Large Scale Structure of UniverseCosmic Background RadiationStellar Dynamics ...Bond, Martin, Kofman, Murray, Pen

25 visitor & fellows9 grad students

Is the Universe Made of These?

Quantum Forces

• In Quantum Field Theory, particles interact via:.

Exchange of virtual particles

Electrons interact by exchanging:

Virtual Photons

Quarks interact by exchanging:

Virtual Gluons

Weak Interaction• A force very like electromagnetism; but

acts on Weak Charge

• In Fact, electromagnetism and weak forceare aspects of unified electroweak force

• Electric charge and weak charge are

related

• Three “force carriers”

W Z 0

W Z 0

Higgs Boson

• Electromagnetism on its own can be made to give finite results for all calculations.

• Unified Electroweak theory gives infinite results for process like:

• Become finite if include new particle

Higgs boson

• Higgs makes massive, and actually generates masses of all particles. It is a quantum field permeating the universe.

W Z 0

How Does Higgs Generate Mass?

• In vacuum, a photon:

has velocity c and has zero mass

• In glass a photon

has velocity < c , same as an effective mass

• This is due to photon interacting with

electromagnetic field in condensed matter

• By analogy can understand masses of particles

generated by Higgs Field in vacuum

Grand Unification.

• At a high enough energy

electromagnetismweak forcestrong (colour) force

become aspects of Grand Unified Force

The Universe is Expanding

Its ultimate fate depends on density of matter and energy

• If , the density of matter and energy is greater that a critical density the universe will start to contract

• If is less than the critical density, the universe will continue to expand.

• Usually measure the density in units of

• spherical space-time: contraction

• flat space-time: expansion

• hyperbolic space-time: expansion

0

0

c

00 0

02

8

3

c

G

H

0 1

0 1

0 1

Experimental Mystery

• Density of Standard Model Matter

• If Universe is made of quarks & leptons

• Find

• Density of all gravitationally interacting matter

• Most of Universe is not Standard Model matter. Some kind of Dark Matter

B

B 0 1

B 0 05.

M 0 0 1.4 .

Measuring

• Amazingly enough can measure

total matter/energy density in universe

• Measure temperature fluctuations in remnant of fireball from Big Bang.

0

0 1

Map of sky temp~ 3 Kelvin

Boomerang: Measuring Fluctuations in Cosmic Microwave Background Radiation.

Gondola with temperaturemeasuring “telescope”

Flight path over Antarctica

Readying for launchMount Terror formsa backdrop.

Need for Supersymmetry

• In Grand Unified Theories cannot Unify forces, unless postulate unseen form of matter

• Higgs mass runs away to Plank Scale• Three forces never have same strength

• Unless all particles have supersymmetric sparticle partners (of higher mass)

+Sleptons BosinosSquarksSpin 1 Spin1/2

SUSY + Dark Matter

• Supersymmetric Particles are unstable

• Eventually decay chain ends in Normal matter + lightest SUSY particle

• Lightest SUSYparticle cannot interact withnormal matter

• Lightest SUSY particle good candidate for

Dark Matter

• Hope to produce

(SUSY - antiSUSY ) pairs and Higgs at

Large Hadron Collider

Susy Normal Susy

How to Make Matter / AntiMatter?

LHC will be proton - proton colliderFermilab is proton - antiprotonHERA is electron - proton

Colliding high energy beams

Energy of beams transformed into mass of new particles

Typical Accelerator Complex

CERN Seen from the Air

• Tunnels of CERN accelerator complex superimposed on a map of Geneva.

• Accelerator is 4.3km in radius 50 m underground

LHC Tunnel

This is an arc of the circular tunnelCircumference 26.7 Km

Collider Detector @ Fermilab

Discovered thesix quark

Top - completes quark generations

UofT involved in upgrading silicon vertex detector

Collider Detector @ Fermilab

Discovered thesix quark

Top - completes quark generations

UofT involved in upgrading silicon vertex detector

Collider Detector @ Fermilab

Discovered thesix quark

Top - completes quark generations

UofT involved in upgrading silicon vertex detector

ZEUS ep Collisions - Proton Structure

Experimental confirmationof equal strength of weak and electromagnetic forces at high energy

Electroweak Unification

ep Collisionseen in ZEUS

ATLAS @ CERN LHC

Computer Simulationof discovery of Higgs Boson