The String TheoryThe String Theory A Theory of EverythingA Theory of Everything

WarningThis journey may change your vision of the Universe. This journey may change your vision of the Universe. What you will hear may alter your perception of reality. What you will hear may alter your perception of reality.

We are entering a Quantum World..

Stay awake and keep an open mind!

Why do we need a single unified theoryWhy do we need a single unified theory What’s missing in the standard model?What’s missing in the standard model? Prescriptions of a unified theoryPrescriptions of a unified theory Gauge theoriesGauge theories Electroweak unificationElectroweak unification Grand unified theoryGrand unified theory Klein Kaluza theoryKlein Kaluza theory ConclusionConclusion

Why Do we need a single theory?

“Everyone’s goal is a theory of everything, an economic, simple theory that works at all energies, at all scales, for all time.”

Why Do we need a single theory? Because there is only One GodBecause there is only One God All the laws should be part of a single pattern.All the laws should be part of a single pattern. A single theory is more beautiful than many theoriesA single theory is more beautiful than many theories The early phases of the universe, only one Universal The early phases of the universe, only one Universal

force called Eventual Unity, is thought to have been force called Eventual Unity, is thought to have been effective.effective.

Like Behavior of Roulette Ball on a Roulette Wheel Like Behavior of Roulette Ball on a Roulette Wheel high energy rolls round & round but at low energy high energy rolls round & round but at low energy drops in to any 37 slats. Low energy 37 states , high drops in to any 37 slats. Low energy 37 states , high energy only one state idea of unification at high energy.energy only one state idea of unification at high energy.

What is Grand Unified Theory?Unified field theory is an attempt to

describe all fundamental forces and the relationships between elementary particles in terms of a single theoretical framework.

Current Fundamental ForcesElectromagneticElectromagneticWeak NuclearWeak NuclearStrong NuclearStrong NuclearGravityGravity

There are four fundamental forces, or interactions in nature.

Strong nuclearStrong nuclear ElectromagneticElectromagnetic Weak nuclearWeak nuclear GravitationalGravitational

Strongest

Weakest

Strong nuclear force

Holds the nuclei of atoms togetherHolds the nuclei of atoms together Very strong, but only over very, very, very Very strong, but only over very, very, very

short distances (within the nucleus of the short distances (within the nucleus of the atom) Responsible for Fission & Fusion. atom) Responsible for Fission & Fusion.

Electromagnetic force Causes electric and magnetic effectsCauses electric and magnetic effects

Like charges repel each otherLike charges repel each other Opposite charges attract each otherOpposite charges attract each other Interactions between magnetsInteractions between magnets

Weaker than the strong nuclear forceWeaker than the strong nuclear force Acts over a much longer distance range Acts over a much longer distance range

than the strong nuclear force ,Also called as than the strong nuclear force ,Also called as (FORCE OF LIFE), Due to generating Bio (FORCE OF LIFE), Due to generating Bio electrical currents in Human Body.electrical currents in Human Body.

Weak nuclear force Responsible for nuclear decayResponsible for nuclear decay Weak and has a very short distance rangeWeak and has a very short distance range

Gravitational force Weakest of all fundamental forces, but acts Weakest of all fundamental forces, but acts

over very long distancesover very long distances Always attractiveAlways attractive Acts between any two pieces of matter in Acts between any two pieces of matter in

the universethe universe Very important in explaining the structure Very important in explaining the structure

of the universe, Can affect space time, time of the universe, Can affect space time, time slows down , space is warped .(Einstein)slows down , space is warped .(Einstein)

The 4 forces of Nature

Weak• Beta-decay• pp fusion

Strong Quark binding

Electromagnetic•TV, PCs • Magnets

• e- e+ creation

GravityResponsible ofKeeping us well-planted on earth

Electric charge

mass

weak charge

strongcharge

The Road to UnificationMagnetism

Light

ElectromagneticElectromagnetic

Weak

AstronomicalMotion

TerrestrialMotion

Electroweak Strong Gravitation

GrandUnification

Single Force

SpaceTime

Weak

Electricity

Quark confinement There are no free quarks, quarks and ant quarks are “confined” in colourless doublet (mesons) or triplets (baryons) by the exchange of gluons

The new quarks boundto the old quarks and form new mesons

until the gluon connection snaps, and other quark-anti quark pairs are created out of the energy released

Gluon hold quarks together as they move further apart

Z0

Decay

® S.Ward

Force Particles (summary)Particles interact and/or decay thanks to forcesForces are also responsible of binding particles together

Strong: gluonsOnly quarks (because of their colour charge)

Weak: W+, W-, Z0

Leptons and quarks (only force for neutrinos)

Electromagnetic: Quarks and charged leptons (no neutrinos)

Gravity: graviton?Still to be discoveredNegligible effects on particles

Beyond the Standard Model:Unification of forces

WEAK

STRONG GRAVITY

ELECTRO-MAGNETIC

UNIFIEDFORCE?

Looking for a simple elegant unified theory

The History of Grand Unified Theory

Electricity and Magnetism Michael Faraday:Michael Faraday: Born: September 22, 1791 Born: September 22, 1791 Died: August 25, 1867Died: August 25, 1867 English physicist and English physicist and chemist whose many experiments chemist whose many experiments contributed greatly to the understanding of contributed greatly to the understanding of

electromagnetism.electromagnetism.

FARADAYS,S LAW OF ELECTROMAGNETIC FARADAYS,S LAW OF ELECTROMAGNETIC INDUCTION.INDUCTION.

Electricity and Magnetism James MaxwellJames Maxwell Born June 13, 1831, Edinburgh, ScotlandBorn June 13, 1831, Edinburgh, Scotland

died November 5, 1879, Cambridge, Cambridgeshire, died November 5, 1879, Cambridge, Cambridgeshire, EnglandEngland

Scottish physicist best known for his formulation of Scottish physicist best known for his formulation of electromagnetic theory.electromagnetic theory.

Incorporated light and wave phenomena into Incorporated light and wave phenomena into electromagnetism electromagnetism

FAMOUS MAXWELL,S EQUATIONSFAMOUS MAXWELL,S EQUATIONS

Electricity and Magnetism In 1905 Einstein’s special theory of In 1905 Einstein’s special theory of

relativity showed that electricity and relativity showed that electricity and magnetism were link and that Maxwell was magnetism were link and that Maxwell was correct.correct.

The single force of Electromagnetism is The single force of Electromagnetism is born.born.

Electroweak Force Sheldon GlashowSheldon Glashow Abdus SalamAbdus Salam Steven WeinbergSteven Weinberg Each physicist independently found that the Each physicist independently found that the

weak nuclear force could be unified with weak nuclear force could be unified with electromagnetic force.electromagnetic force.

Electroweak Force At extremely high energies, 10At extremely high energies, 101515 GeV the GeV the

electromagnetic and weak forces become the electromagnetic and weak forces become the same.same.

The relationship is based on the exchange of The relationship is based on the exchange of four particles: the photon of EM interactions, four particles: the photon of EM interactions, two charged W particles and a neutral Z two charged W particles and a neutral Z particle.particle.

Weak force: W-,W+,Z0

decayn→pee

Electric chargeconserved at eachvertex

W-

Electroweak Force

Strong Nuclear Force Quantum Chromo dynamics was developed to Quantum Chromo dynamics was developed to

explain strong force during the 1970s.explain strong force during the 1970s. Quarks are believed interact by exchanging Quarks are believed interact by exchanging

gluons.gluons. The hope is to use that similarity to unify strong The hope is to use that similarity to unify strong

with electroweak force.with electroweak force. The unification cannot be found because energy The unification cannot be found because energy

levels 10levels 101212 higher than those needed to develop the higher than those needed to develop the electroweak force are required to test further electroweak force are required to test further unification.unification.

Strong Nuclear Force

Gravity Newton showed that both Newton showed that both

astronomical and terrestrial motion could be astronomical and terrestrial motion could be explained with gravitationexplained with gravitation

In 1915 Einstein’s theory of general relativity In 1915 Einstein’s theory of general relativity was written in which concept on Anti Gravity & was written in which concept on Anti Gravity & Black hole was given .Black hole was given .

Einstein spent 30 years trying to unify EM with Einstein spent 30 years trying to unify EM with gravity and failed.gravity and failed.

General Relativity The equivalence principle: The equivalence principle:

gravity and acceleration are equivalent – gravity and acceleration are equivalent – i.e., one cannot discriminate between i.e., one cannot discriminate between being at rest in a gravitational field and being at rest in a gravitational field and being accelerated in the absence of being accelerated in the absence of gravity gravity

gravity = acceleration

General Relativity

Mass causes space-time to curve: Mass causes space-time to curve: Imagine space-time as a four-Imagine space-time as a four-

dimensional rubber sheet. Any object dimensional rubber sheet. Any object with mass causes this sheet to become with mass causes this sheet to become deformed. deformed.

General Relativity The curvature of space-time tells matter The curvature of space-time tells matter

how to move: how to move: What we perceive as gravity arises What we perceive as gravity arises

from the curvature of space-time. from the curvature of space-time. Masses follow the ‘straightest Masses follow the ‘straightest possible paths’ possible given the possible paths’ possible given the curvature. curvature.

Escape velocity from a black hole

Remember (from Chapter 5) the escape Remember (from Chapter 5) the escape velocity is given byvelocity is given by vvescesc = [2GM/R] = [2GM/R]1/21/2

what if the escape velocity was equal what if the escape velocity was equal to the speed of light? to the speed of light?

this would set a maximum radius for this would set a maximum radius for which light could escape from an which light could escape from an object with a given massobject with a given mass

The Schwarzschild radiusThe Schwarzschild radius

vv22escesc = [2GM/R] = [2GM/R] = c= c22

RRSS = 2GM/c = 2GM/c22

or Ror RSS = [3.0 x M/M = [3.0 x M/Msunsun] km] km

The Schwarzschild radius

the larger the mass of a black hole, the the larger the mass of a black hole, the larger the Schwarzschild radiuslarger the Schwarzschild radius

once light or any object has crossed the once light or any object has crossed the Schwarzschild radius (or event horizon), it Schwarzschild radius (or event horizon), it can never escape the force of gravity of the can never escape the force of gravity of the black hole.black hole.

Black holes have no hair all information about the material that all information about the material that

is inside the event horizon of a black is inside the event horizon of a black hole is lost, hole is lost, exceptexcept massmass chargecharge angular momentumangular momentum

Black hole Entropy Theorem

The total amount of information (entropy) The total amount of information (entropy) in the Universe cannot decrease (second in the Universe cannot decrease (second law of thermodynamics)law of thermodynamics)

this is what lead Bekenstein and Hawking this is what lead Bekenstein and Hawking to the idea that Black holes must radiateto the idea that Black holes must radiate

Falling into a black hole stretched by tidal forcesstretched by tidal forces time slows downtime slows down radiation is redshiftedradiation is redshifted

Observational Evidence

there is evidence that black holes formed from there is evidence that black holes formed from collapsed stars exist in some X-ray binariescollapsed stars exist in some X-ray binaries

most promising candidate: most promising candidate: Cygnus X-1: 18 MCygnus X-1: 18 Msunsun star orbiting an star orbiting an

unseen companion with a mass of 10 Munseen companion with a mass of 10 Msunsun

too massive to be a neutron star and too too massive to be a neutron star and too small to be an ordinary starsmall to be an ordinary star

Supermassive Black Holes

there is very good evidence from the there is very good evidence from the motions of stars and gas near the centers of motions of stars and gas near the centers of galaxies that most galaxies (including our galaxies that most galaxies (including our own) contain ‘supermassive black holes’ – own) contain ‘supermassive black holes’ – black holes weighing millions to billions of black holes weighing millions to billions of solar massessolar masses

how these objects formed is still something how these objects formed is still something of a mystery…of a mystery…

White holes, Wormholes, and tunnels through hyperspace black holes are only one of the several black holes are only one of the several

kinds of singularities in the equations of kinds of singularities in the equations of general relativitygeneral relativity

white holes are sort of like the opposite of white holes are sort of like the opposite of black holesblack holes

a wormhole is a black hole connecting to a a wormhole is a black hole connecting to a white hole white hole

Einstein-Rosen bridge

Wormhole

The Future of the Grand Unified Theories

Gravity may be unified by superstring theory, Gravity may be unified by superstring theory, which is the best theory right now for unification.which is the best theory right now for unification.

Higher energy experiments are needed to study the Higher energy experiments are needed to study the strong nuclear force and its unification with strong nuclear force and its unification with electroweak.electroweak.

More study of electroweak is still needed. By More study of electroweak is still needed. By using the simplest version of the theory a using the simplest version of the theory a calculation was performed that determined a calculation was performed that determined a proton life several orders of magnitude too short, proton life several orders of magnitude too short, from 10from 102929 to 10 to 103131 years. years.

show that the life of a proton is greater than show that the life of a proton is greater than 10103232 years. which means that one proton years. which means that one proton decay vs. decay vs. 10103232 show that the life of a proton is show that the life of a proton is greater than 10greater than 103232 years. which means that one years. which means that one proton decay vs. 10 to the power 32/ yearproton decay vs. 10 to the power 32/ year

Why is the Universe made of matter and not equally of anti-matter?

We have seen that for every fundamental particle there We have seen that for every fundamental particle there is a corresponding antiparticle.is a corresponding antiparticle.

Where are these anti-particles? Where are these anti-particles?

Large amount of matter but no evidence of large Large amount of matter but no evidence of large amount of antimatter in the Universe .Good Luck! amount of antimatter in the Universe .Good Luck! Otherwise Existence of Universe is not possible.Otherwise Existence of Universe is not possible.....

Why has all the anti-matter gone?

Anti-matter

The development of the Universe containing matter and no antimatter requires that matter and antimatter behave differently

This phenomenon is due to CP violation..

matter Puff

Good thing for us that there is no antimatter around!

CP Violation CCPP = = CCharge Conjugation (reverse charge) x harge Conjugation (reverse charge) x PParity (reverse arity (reverse

spatial coordinates as in a mirror)spatial coordinates as in a mirror)

CPCP

beauty anti-beautyB0 B0

“Nobody is perfect”

CP-Violation: B0 and B0 do not behave exactly in the same way (their decay pattern as a function of time is different) For GUTS CP(OK),CPT(not ok) THAT IS Direction reversal symmetry breaks down.

53

The String Theory: The Wholly GrailThe String Theory: The Wholly Grail A theory to unify quantum A theory to unify quantum

mechanics and general mechanics and general relativity (all known forces).relativity (all known forces).

Every particle boils down to Every particle boils down to vibrating strings .vibrating strings .

The difference in vibrational The difference in vibrational strings makes up each atom strings makes up each atom and gives them their and gives them their properties.properties.

All forces (and phenomena) All forces (and phenomena) in existence described in in existence described in one equation. (Space time one equation. (Space time unification) Emission & unification) Emission & Absorption of particles take Absorption of particles take place through open and place through open and close strings like two legs in close strings like two legs in a trouser, upper one , lower a trouser, upper one , lower two , some times two , some times open ,some times close.open ,some times close.

LIGHT and GRAVITYin STRING THEORY

STRING THEORY String theory offers us surprises of String theory offers us surprises of

comparable magnitude. comparable magnitude. The elements in Einstein’s synthesis were The elements in Einstein’s synthesis were

space and time.space and time. The surprising synthesis emerging from The surprising synthesis emerging from

String theory in the last decade or so String theory in the last decade or so involves two other familiar elements of our involves two other familiar elements of our experience : Light and Gravity. experience : Light and Gravity.

Maxwell’s Electromagnetic theory of light ( pre-20’th Maxwell’s Electromagnetic theory of light ( pre-20’th century ) when developed to incorporate the insights of century ) when developed to incorporate the insights of quantum mechanics and relativity ( early 20’th century ) quantum mechanics and relativity ( early 20’th century ) gives rise to a new framework : gives rise to a new framework :

Quantum field theory ( QFT ) Quantum field theory ( QFT ) – – mid-20’th centurymid-20’th century

Light and Photons

In QFT, light can be viewed as an elementary In QFT, light can be viewed as an elementary particle, called the photonparticle, called the photon

QFT provides a new way to understand force : QFT provides a new way to understand force : Force is due to the exchange of elementary Force is due to the exchange of elementary particles particles

Electric Force between particles e.g. electrons Electric Force between particles e.g. electrons is due to the exchange of photons ( light ) is due to the exchange of photons ( light )

Hence QFT is the language of the Standard model of Hence QFT is the language of the Standard model of Particle Physics (discovered by Weinberg and Salam Particle Physics (discovered by Weinberg and Salam ) which has been tested to extremely high accuracy in ) which has been tested to extremely high accuracy in accelerators around the world.accelerators around the world.

QFT and Strong Force Electrons spread to the outskirts of atoms. The core Electrons spread to the outskirts of atoms. The core

of atoms consists of nuclei, made of protons and of atoms consists of nuclei, made of protons and neutrons. Protons and neutrons are themselves made neutrons. Protons and neutrons are themselves made of quarks. of quarks.

QFT can also account for sub-nuclear forces QFT can also account for sub-nuclear forces between quarks. between quarks.

The mediators of the ( strong ) force between The mediators of the ( strong ) force between quarks are gluons. quarks are gluons.

Photons, Gluons , Large N Photons – force between electric charge. Photons – force between electric charge. One kind of charge ( one number, positive or One kind of charge ( one number, positive or

negative ) . One kind of photon. negative ) . One kind of photon.

Quarks come in 3 colours. Hence gluons come in Quarks come in 3 colours. Hence gluons come in multiple types, depending on which quarks they multiple types, depending on which quarks they mediate between.mediate between.

A simple mathematical generalization consists of A simple mathematical generalization consists of imagining theories with N quarks and N^2 gluons. imagining theories with N quarks and N^2 gluons.

WHY STRINGS ? QFT , while successful in describing QFT , while successful in describing

electromagnetic and sub-nuclear forces, is not so electromagnetic and sub-nuclear forces, is not so successful in describing the force of gravity. successful in describing the force of gravity.

Rather we need String Theory, which is a new Rather we need String Theory, which is a new paradigm whereby fundamental constituents of the paradigm whereby fundamental constituents of the world are lines – not points. world are lines – not points.

A multiplicity of particles arises from different A multiplicity of particles arises from different vibration modes of the same string.vibration modes of the same string.

Weak Gravity In the limit of weak gravity, we In the limit of weak gravity, we

recover Newton’s gravity, which recover Newton’s gravity, which describes most planetary orbits to describes most planetary orbits to reasonable accuracy.reasonable accuracy.

Strong Gravity In the limit of strong gravity, the Einstein In the limit of strong gravity, the Einstein

equations describe black holes …equations describe black holes …

•ON very large cosmological scales, it describes the expansion of the Universe.

A String duality between Light and Gravity

In string theory, light ( and its large N In string theory, light ( and its large N generalization ) arises from the same object as generalization ) arises from the same object as gravitons. This leads to the unexpected relation : gravitons. This leads to the unexpected relation :

Gravity for space-time in the shape of a solid ball Gravity for space-time in the shape of a solid ball in five dimensions is equivalent to a theory with no in five dimensions is equivalent to a theory with no gravitons but with large N-light propagating on the gravitons but with large N-light propagating on the four dimensional surface four dimensional surface

of the ball. of the ball.

STRING : gluon and graviton Vibrations of an open string give rise to gluons.Vibrations of an open string give rise to gluons.

Vibrations of closed string -- graviton ( since 70’s ) Vibrations of closed string -- graviton ( since 70’s )

Gravitons and Gravity

Graviton exchange .… force of gravity.Graviton exchange .… force of gravity. Charges replaced by masses. Charges replaced by masses. Photon replaced by graviton. Photon replaced by graviton. By using symmetries of the stringBy using symmetries of the string world-sheet, one can recover the equations world-sheet, one can recover the equations

of general relativity. of general relativity.

67

Problems With The String Problems With The String TheoryTheory Theory included a particle (a Tachyon) that was Theory included a particle (a Tachyon) that was

faster than the speed of light.faster than the speed of light. Theory required multiple dimensions like 10 or 26 Theory required multiple dimensions like 10 or 26

space time dimensionsspace time dimensions. More be the dimensions . More be the dimensions lesser be the curve , sple be the motion, easily lesser be the curve , sple be the motion, easily understandable.understandable.

No observation or experiment could discount the No observation or experiment could discount the theory.theory.

The mass-less particle. Later proposed as the The mass-less particle. Later proposed as the graviton. A particle that governs gravity at atomic graviton. A particle that governs gravity at atomic level and ultimately decided how small the strings level and ultimately decided how small the strings are.are.

If an atom were the size of the solar system, a string If an atom were the size of the solar system, a string would be the size of a tree.would be the size of a tree.

68

The String Theory The String Theory ExpandsExpands

If we could master the rhythms of strings If we could master the rhythms of strings then we could explain all the matter, then we could explain all the matter, forces, and phenomena in nature from the forces, and phenomena in nature from the biggest things (planets, galaxies) to the biggest things (planets, galaxies) to the smallest quantum particles.-Idea if Higgs smallest quantum particles.-Idea if Higgs that is H particle particle in universe that that is H particle particle in universe that is between earth & sun is equivalent to is between earth & sun is equivalent to Gluon exchange between Gluon exchange between Quarks.Quarks.

69

The Possibilities are The Possibilities are InfiniteInfinite

11 dimensions were needed for 11 dimensions were needed for the 5 string theories to combine the 5 string theories to combine into one. Multi-dimensions are at into one. Multi-dimensions are at the heart of the string theory.the heart of the string theory.

The degrees of freedom we (and The degrees of freedom we (and what we can observe) have what we can observe) have locked us in to three dimensions locked us in to three dimensions of space and one of time. While of space and one of time. While strings do not have the same strings do not have the same limitations they can traverse all limitations they can traverse all 11 dimensions.11 dimensions.

The 11The 11thth dimension allows strings dimension allows strings to stretch into membranes that to stretch into membranes that can grow to enormous sizes (like can grow to enormous sizes (like the size of a universe). the size of a universe).

Eleven dimensions, parallel universes, and a world made out of strings. It's not science fiction, it's string theory.

70

Science or PhilosophyScience or Philosophy We live in a three dimensional plate We live in a three dimensional plate

that traverses a 11 dimensional that traverses a 11 dimensional spatial universe.spatial universe.

It is conceivable that our universe is It is conceivable that our universe is just one membrane that is a part of just one membrane that is a part of an infinite number of membranes. an infinite number of membranes. However, those membranes could However, those membranes could reside in 5, 6, or 7 dimensions. reside in 5, 6, or 7 dimensions. Therefore, they could be right next Therefore, they could be right next to us but our three dimensional to us but our three dimensional existence could never interact with existence could never interact with them, but strings could.them, but strings could.

Multi dimensions could explain why Multi dimensions could explain why gravity is so weak in our universe. gravity is so weak in our universe. Gravity could be just as strong as Gravity could be just as strong as the other forces, but gravity could the other forces, but gravity could be a force that works in 5 or 6 be a force that works in 5 or 6 dimensions and is weak in our three dimensions and is weak in our three dimensional space.dimensional space.

71

Implications for E.T.Implications for E.T. The theory has pre-big The theory has pre-big

bang explanations.bang explanations. Two membranes in a Two membranes in a

four dimensional space four dimensional space collided and all the laws, collided and all the laws, constants, and make up constants, and make up from the two four from the two four dimensional membranes dimensional membranes combined into our combined into our existence.existence.

There is no reason why There is no reason why life (intelligent) has to life (intelligent) has to be limited to four be limited to four dimensions.dimensions.

72

More Implications for More Implications for E.T.E.T. Would a proven theory make it harder or easier to Would a proven theory make it harder or easier to

search for Everything.search for Everything. Would this expand our possibilities?Would this expand our possibilities? The theory accounts for hyperspace, traveling faster The theory accounts for hyperspace, traveling faster

than light, multiple dimensions, strings traversing than light, multiple dimensions, strings traversing different universes.different universes.

Will the theory help in Will the theory help in finding bacterial life finding bacterial life forms since forms since it can determine the behavior of basically everything at it can determine the behavior of basically everything at its core (i.e. where certain particles, bacteria, is its core (i.e. where certain particles, bacteria, is limited to, how nature “picks” certain molecules)?limited to, how nature “picks” certain molecules)?

Will knowing the behavior of everything about our four Will knowing the behavior of everything about our four dimensional universe help us flesh out where we dimensional universe help us flesh out where we should look in our Multi dimensional universe?should look in our Multi dimensional universe?

Can the theory go far enough to determine how Can the theory go far enough to determine how humans came to be and the possibilities of it humans came to be and the possibilities of it happening elsewhere?happening elsewhere?

Kaluza-Klein theory Kaluza-Klein added one extra spatial Kaluza-Klein added one extra spatial

dimension to our conventional space-dimension to our conventional space-time.time.

Introduced 5-D metric tensor , which can be decomposed into two parts

What have we learnt? A number of surprising things:A number of surprising things:

A limited number of A limited number of forces and matter particlesforces and matter particles describe all describe all the Universe we know about;the Universe we know about;

A theory of the interactions of matter with forces called the A theory of the interactions of matter with forces called the Standard ModelStandard Model describes successfully the phenomena of describes successfully the phenomena of the subatomic world; the subatomic world;

There are evidences that there is lot more that we do not There are evidences that there is lot more that we do not know about and our research should find: such as the know about and our research should find: such as the missing anti-mattermissing anti-matter, , dark matterdark matter, , puzzling neutrino puzzling neutrino properties, but also the Standard Model key-vault ..the properties, but also the Standard Model key-vault ..the HiggsHiggs!!

Looking into the future The Higgs should be found at the LHC…The Higgs should be found at the LHC…

please be patient for a few more please be patient for a few more hours….and you will learn about the Higgs, hours….and you will learn about the Higgs, the LHC, and much more! the LHC, and much more!

NOT

Conclusion

Physicists are trying to find a single theory that Physicists are trying to find a single theory that explains the whole universe. I think that there will explains the whole universe. I think that there will always be some gaps. always be some gaps. The part of the universe that The part of the universe that we can perceive is very small compared to the part we can perceive is very small compared to the part we can notwe can not. Cosmological observations (e.g., dark . Cosmological observations (e.g., dark matter, dark energy,…) indicate that we are still matter, dark energy,…) indicate that we are still crawling under the mountain of a single unified crawling under the mountain of a single unified theorytheory

Conclusion (Continued)

Physics at TeV scale likely to be richPhysics at TeV scale likely to be rich To fully understand it, we will likely need To fully understand it, we will likely need a a

lotlot of detailed information of detailed information LC will study new particles one by oneLC will study new particles one by one

reconstruct the fundamental Lagrangianreconstruct the fundamental Lagrangian Then we would like to move on further with Then we would like to move on further with

absolute confidenceabsolute confidence

Dark Matter likely to be TeV-scale Dark Matter likely to be TeV-scale electrically neutral weakly interacting electrically neutral weakly interacting particle (particle (e.g.e.g., LSP, Lightest KK), LSP, Lightest KK)

With LC, measure its mass, couplingsWith LC, measure its mass, couplings Can calculate its cosmic abundanceCan calculate its cosmic abundance If it agrees with cosmological observation, If it agrees with cosmological observation,

we understand Universe back to 10we understand Universe back to 10–12–12 sec sec after the Big Bangafter the Big Bang

Produce Dark Matter

80

References and References and InformationInformation http://superstringtheory.com/experm/exper3.html - Basics of http://superstringtheory.com/experm/exper3.html - Basics of

String TheoryString Theory http://superstringtheory.com/basics/basic5.html - Basics of http://superstringtheory.com/basics/basic5.html - Basics of

String TheoryString Theory http://www.sukidog.com/jpierre/strings/ - Basics of String http://www.sukidog.com/jpierre/strings/ - Basics of String

TheoryTheory Superstrings: A Theory of Everything?Superstrings: A Theory of Everything?, ed. P.C.W. Davies and , ed. P.C.W. Davies and

J. Brown, Cambridge University Press, 1988;J. Brown, Cambridge University Press, 1988; E. Witten, Reflections on the Fate of Spacetime, Physics E. Witten, Reflections on the Fate of Spacetime, Physics

Today, April 1996. Today, April 1996. http://public.web.cern.ch/Public/Welcome.html - CERN http://public.web.cern.ch/Public/Welcome.html - CERN

WebsiteWebsite Hyperspace: A Scientific Odyssey Through Parallel Universe, Hyperspace: A Scientific Odyssey Through Parallel Universe,

Time Warps, And The Tenth DimensionTime Warps, And The Tenth Dimension by Michio Kaku by Michio Kaku The Elegant Universe; Superstrings, Hidden Dimensions, And The Elegant Universe; Superstrings, Hidden Dimensions, And

The Quest For The Ultimate TheoryThe Quest For The Ultimate Theory by Brian Greene by Brian Greene

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