20121011 Higgs Thaler

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The Higgs Boson

Jesse Thaler

Higgs-like Celebration Oct 11, 2012

Triumph of the Standard Model

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Jesse Thaler The Higgs Boson

Higgs-like DiscoveryJuly 4, 2012

This talk: Why the Higgs is such a big deal

= Affiliated (past or present) with MIT

8.05 = Shout out to my recitation students

Culminating a centuryof particle physics!

Defining next 25 years

of fundamental physics!

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QuantumGravity

Protons

Electrons

Cells

Molecules

TheUniverse

TheTeVScale

HairsUs

SolarSystem

Planet

Galaxy

GrandU

nification

1011m 10

4m 10

19m 10

34m10

26m

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QuantumGravity

Protons

Electrons

Cells

Molecules

TheUniverse

TheTeVScale

HairsUs

SolarSystem

Planet

Galaxy

GrandU

nification

1011m 10

4m 10

19m 10

34m10

26m

The Standard Model

Quarks Leptons

+Graviton Photon Gluon W/Z Bosons

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QuantumGravity

Protons

Electrons

Cells

Molecules

TheUniverse

TheTeVScale

HairsUs

SolarSystem

Planet

Galaxy

GrandU

nification

1011m 10

4m 10

19m 10

34m10

26m

The Standard Model

Quarks Leptons

+Graviton Photon Gluon W/Z Bosons

+ Higgs!

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Essential for Stellar Burning

Deuteron

W boson

_

Weak Force

Weak Alchemy

Electromagnetic

photon W boson

(unchanged) (!)

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Three Bizarre Properties

1. Massive Carrier

MasslessPhoton

Two Polarizations

3D glasses!Massive

W Boson

8.05: spin-1 has m = 1, 0, +1

+ ?

Three Polarizations

3. (Parity-Violating) 8.05: x x is not a symmetry of weak force

2. Self-Interacting

PhotonPass rightthrough

W

vs.

Collision

Photon

W

W

W

vs.= =

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Why is Weak Force so Weird?

8.325: Spontaneous Symmetry Breaking

Because Weak Force is Broken

8.05: Weak charge is not conserved

Analogy: Why is ice so weird compared to water?

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Why is Weak Force so Weird?

8.325: Spontaneous Symmetry Breaking

Because Weak Force is Broken

8.05: Weak charge is not conserved

Higgs!

Analogy: Why is ice so weird compared to water?

Caused by the Higgs!

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Energy NotConserved in

Weak Decays??

n p e

A Little History

Expt:

Theory:

1920s

Chadwick, et al.

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Weak Decays??

n p e

A Little History

Expt:

Theory:

1920s

1930 1933

n p e?Pauli Fermi

Chadwick, et al.

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Weak Decays??

n p e

A Little History

Expt:

Theory:

1920s

1930 1933

n p e?Pauli Fermi

Chadwick, et al. Cowan/Reines

1956

!

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Weak Decays??

n p e

A Little History

Expt:

Theory:

1920s

1930 1933

n p e?Pauli Fermi

Chadwick, et al.

New ParticleNeutrino Energy Conservation

Fundamental PrincipleLessons:

Have to take the long view

Cowan/Reines

1956

!

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A Little History

Theory:


Weak Decays??

n p e

Expt: 1920s


1956

!

1930 1933

n p e?Pauli Fermi

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A Little History

Theory:


Weak Decays??

n p e

Expt: 1920s


1956

!

1930 1933

n p e?Pauli Fermi

1967

Weinberg/Salam/Glashow

n

p e

via New Weak Force?

W? Weak AlchemyW+? (Reverse) Weak Alchemy

Z? Zomething else...

Three New Force Carriers:

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A Little History

Theory:

1983

Rubbia/van der Meer

SPS @ CERN

W/Z!


Weak Decays??

n p e

Expt: 1920s


1956

!

1930 1933

n p e?Pauli Fermi

1967


n

p e

via New Weak Force?

W? Weak AlchemyW+? (Reverse) Weak Alchemy

Z? Zomething else...

Three New Force Carriers:

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History in the Making?

Expt:

Theory:

1920s

1930 1933

1956

1967

1983

W/Z!!

? W/Z?

n p e?

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History in the Making?

Expt:

Theory:

1920s

1930 1933

1956

1967

1983

W/Z!

1964

h?

!

? W/Z?

n p e?

2012

h! (?)

48 years

Higgs boson: Last ingredient of Standard Model

Prof. Klutes talk: Higgs or just Higgs-like?

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Higgs Mechanism

Breaks Weak ForceGives Mass to

Fundamental Particles

M Higgs Boson

New Spin-0 ParticleEnsures Consistency of

Quantum Mechanics

%

Tale of Two Higgses

Massive W Boson W Self-Collisions

W

CollisionW

W

W

+ ?

Higgs

!

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8.05: Composites (likeproton) get most mass

from strong force

M Higgs Mechanism in 2012Mass for all Fundamental Particles

For Prof. Klutes talk:

Higgs Couplings

Particle Masses

Higgs

!

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?

M Higgs Mechanism in 1964

The Anderson, Brout/Englert, Higgs*,Guralnik/Hagen/Kibble, 't Hooft Mechanism

TwoPolarizations

+

(1964)

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?



TwoPolarizations

+

(1964)

Nambu/GoldstoneBoson

(Necessary consequenceof breaking)

(1961)

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?


ThreePolarizations!

=


TwoPolarizations

+

(1964)



(1961)

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?


(Optional?) consequence of breakingis extra particle: Higgs boson

8.05: Higgs boson is spin-0

*

ThreePolarizations!

=


TwoPolarizations

+

(1964)



(1961)

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PhotonUnbroken, Massless,

Long Range

M Birth of the Standard ModelKiller App for Higgs Mechanism: Electroweak Theory

W/Z BosonsBroken, Massive,

Short Range!

(1967)


= Standard Model+ +

Politzer/Gross/Wilczek

(1973)

Higgs

!

+

Higgs Boson

+

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Higgs Boson?(Keystone or Appendix?)

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% Colliding Weak Bosons

Eeff

P

1 TeV 14 TeV

100%

0%

W

W

W

W

Quantum Mechanics = Theory of Probability

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100% chance something will happen8.05: take 8.06 to learn what 100% really means


Eeff

P

1 TeV 14 TeV

100%

0%

W

W

W

W


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100% chance something will happen8.05: take 8.06 to learn what 100% really means


Eeff

P

1 TeV 14 TeV

100%

0%

Violation of QM??

W

W

W

W


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Prof Klutes talk: Higgs hunting = Bump hunting

% Enter the Higgs Boson

Eeff

P

1 TeV 14 TeV

100%

0%

A Higgs-likeParticle!

W

W

W

W

Rescuing Quantum Mechanics

particlezoo.net

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The Weak Interaction

A Bizarre Force...

Higgs MechanismBreaks Weak ForceGives Mass to

Fundamental Particles

Higgs BosonNew Spin-0 ParticleEnsures Consistency of

Quantum Mechanics

...with a Profound Prediction

3. (Parity-Violating)

1. Massive Carrier

2. Self-Interacting

0. Weak AlchemyM

%

Higgs

!

G

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QuantumGra

vity

Pro

tons

Elect

rons

Cells

Molecules

TheUniverse

TheTeVS

cale

H

airsUs

SolarSystem

Planet

Ga

laxy

GrandUnifica

tion

1011m 10

4m 10

19m 10

34m10

26m

The Standard Model

New Particles Fundamental Principles

Neutrino Energy Conservation

W/Z Bosons Essential Similarity of All Forces

Higgs Boson Probability Conservation

+ Higgs!

QG

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QuantumGra

vity

Pro

tons

Elect

rons

Cells

Molecules

TheUniv

erse

TheTeVS

cale

H

airsUs

SolarSystem

Planet

Ga

laxy

GrandUnifica

tion

1011m 10

4m 10

19m 10

34m10

26m

The Standard Model

New Particles Fundamental Principles

Neutrino Energy Conservation

W/Z Bosons Essential Similarity of All Forces

Higgs Boson Probability Conservation

Dark Matter? ??

?? Supersymmetry?An exciting future for

fundamental physics!

+ Higgs!

20121011 Higgs Thaler

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