Topic 19

Particle Physics

Fundamental Forces

Hadrons - quarks - structure inside nucleon

Leptons

Modern Physics Lecture 25, Slide 1

Structure of a proton?

Lecture 25 - Slide 2

neutrons

protons

u

u

d

u

d

d

Quarks “Flavors”

Lecture 25 - Slide 3

Charge = +2/3

Charge = -1/3

Anti-matter

Lecture 25 - Slide 4

Protons

Charge = +1

u u

d

Anti-protons

Charge = -1

u u

d

p+ meson

Charge = +1u d

Structure of a proton?

Lecture 25 - Slide 5

neutrons

protons

u

u

d

u

d

d

e-

leptons

Lecture 25 - Slide 6

Charge = 0

Charge = -1

Gluons

Lecture 25 - Slide 7

Gauge

Boson u u

d

Every

must be

“color”

neutral

All together

Lecture 25 - Slide 8

• Why are there three families of quarks and

three families of leptons? Why the mass

difference?

Questions

• Why is there more matter than anti-matter?

• Are there particles we haven’t detected yet?

More neutrinos?

• Why is gravity so weak?

• Why are neutrinos so light? What is their mass?

Which one is heaviest?

• What is the muon’s dipole moment?

• What is the radius of the proton?

Lecture 25 - Slide 10

The main purpose of Fermilab is to provide an accelerator

to study the fundamental nature of matter and energy.

Accelerator allows physicists to look at the structure

inside the proton.

Only about half of the people that work at Fermilab work

for Fermilab. The rest are visiting scientists (fraction

depends on the status of the accelerator).

Most of the people that work for Fermilab are not physicists. The majority are engineers,

operators and support staff.

Fermilab has a small but growing number of people working in astrophysics and

cosmology.

Kinetic energy of the accelerated particles turns into

matter via E=mc2. Velocity of particles ~ c.

u

uu d

u

d

anti-proton

(3 anti-quarks)

proton

(3 quarks)

(Not “atom smasher”)

Collisions

u

du

uE=mc2

Bam!

Collisions

u

d u

uNow anything(!) can come out.

(In fact, hundreds of “anythings”!)

Collisions

There are conservation laws (like 2111)

• Charge

• Mass/Energy

• Spin

• Lepton number

• Hadron number

• Weak force can quark flavor

Conservation

Crockcroft-

Walton

Linear

Accelerator

(Linac)

(0.405 GeV)

Booster

(8 GeV)

Main Injector

(120/150 GeV)

Protons and

Anti-protons go

in Tevatron

(980 GeV)

Some Protons

used to make

“PBars”

Collisions take place

at detector halls

CDF

D0

How we used to run

Most of the trick is

engineering!!

CDF Detector (no longer in use)

RFQ

Linear

Accelerator

(Linac)

(0.405 GeV)

Booster

(8 GeV)

Main Injector

(120/150 GeV)

Protons and

Anti-protons go

in Tevatron

(980 GeV)

Store muons

How we run now

Make neutrinos

and shoot them

to Minnesota

Highest energy portion

of accelerator turned off

Shoot neutrinos through the earth!

Lecture 24 - Slide 19

Here is where

we are.

Last steps changes if we

want to send neutrinos to

Minnesota!

The whole thing

Muon g-2 magnets

Slide 21

Moved from New York without warping +/- 3mm

Blanco

Telescope in

Chile to be

used in Dark

Energy Survey

Astrophysics/Cosmology

Fermilab

involved in

astrophysics /

cosmology

Blanco

Telescope in

Chile to be

used in Dark

Energy Survey

Astrophysics/Cosmology

570Megapixel Camera

goes here!

~1475lb

-100 oC

10-6 Torr

Allow to be oriented in

any direction

Blanco

Telescope in

Chile to be

used in Dark

Energy Survey

Astrophysics/Cosmology

You came in here.

(East towards COD )

We’re here.

“The Village” where

students and visitors live

(One big party in the

summer).

Buffalo hang out here.

Lederman Science

Education Center.

Muon Storage RingTowards Minnesota