1. The idea behind particle accelerators (atom smashers):
________ particles
+ high __________:
old
energy
_______ particles because
________
new
E = mc2
The more the ________________ given to the old particles,
the more _________________ of the new ones by E = ______.
energy
the mass
mc2

2. Ex: Early particle accelerators
used _______________ generators:
van derGraff
high _______________
work done on
a charge q:
W =
high _______________
work done on
a charge q: W=
voltage V qV
Ex: How much KE will a proton gain when it is
accelerated through a potential difference of 300,000 V?
W = qV
= DKE
v ~ 7.6 x 106 m/s
crosses the Earth
in 1.7 s, but still
only 2.5% of c
W =
(1 e)(300,000 V)
W =
300,000 eV

3. Ex: An example of a modern particle accelerator is
the_____________________ .
cyclotron. v v v
The _______________ field accelerates the particle.
The ______________ field is ____________________ to v, so it
only causes the particle to ___________________________ .
electric
magnetic
perpendicular
turn in a circle

4. the very
first cyclotron
world’s biggest
cyclotron
a 1939 cyclotron

5. The particle accelerator
at Cornell University
accelerator
storage ring
for positrons

6. SLAC – The Stanford Linear Accelerator Center

8. Fermilab in Chicago – another accelerator
built in the shape of a circle.

9. Find the ladder for scale.
…inside Fermilab

10. One of the largest – at CERN - Angels and Demons

11. A detector at CERN
led to the discovery
of the W and Z
particles – carriers of
the weak force

12. As accelerators with higher and higher _____________ were built, particles with bigger and bigger ____________were discovered.
energy
masses
There seemed to be no _____________
to the________________ of newly
discovered particles.
pattern
hundreds
_____________________
tracks of subatomic
particles
Finally, the _________________________ was worked out in
the _______________ . It explained how all of the particles
are made of ________________ fundamental particles and
their _________________________ .

14. bubble chamber tracks

15. As accelerators with higher and higher _____________ were built, particles with bigger and bigger ____________were discovered.
energy
masses
There seemed to be no _____________
to the________________ of newly
discovered particles.
pattern
hundreds
_____________________
tracks of subatomic
particles
Finally, the _________________________ was worked out in
the _______________ . It explained how all of the particles
are made of ________________ fundamental particles and
their _________________________ .
Standard Model
1960s
twelve
antiparticles

16. The Standard Model: All matter (or antimatter) is
made up of ___________or combinations of____________.
leptons
quarks
_______
quarks
leptons
Let’s look
at leptons first.
__________________
read the fine print

18. increasing____________________
mass/energy
only found at
high energies
(high temps.)
everyday
low-energy
leptons
Neutrinos
have _______
_____ mass.
almost no
Lepton means________________________
Leptons all have charge _______or__________________
Their antiparticles are charged __________________
They occur____________________—they do not
___________________________________________.
“light weight.”
-1e
0 (neutral).
+1e or 0.
by themselves
combine to form bigger particles

19. increasing __________________
everyday,
low-energy
quarks
mass/energy
only found at
high energies
(high temps.)
Quarks all have charge _________or ___________
Their antiparticles are charged _________ or_________
They ___________________by themselves because you
cannot have a particle with a_________________________.
They occur in groups of _____________________
(+2/3)e
(-1/3)e.
(+1/3)e
(-2/3)e
never occur
non-integer charge
2’s or 3’s.

20. particles
made from
___________
quarks
“mes-”
means
_________
masses
“bary-”
means
_______
masses
middle
heavy
qqq q
Must be all
__________ or
all_____________ or
matter
antimatter q

21. Ex. A certain particle is made up of
3 quarks: 2 ________ quarks and
1 _____________ quark. u d up u
down
What is the total charge of the particle? u:
Add up the charges:
(+2/3) e u:
(+2/3) e
[(+2/3) + (+2/3) + (-1/3)] e d:
(-1/3) e
= 1 e
Is this a baryon, a meson or a lepton?
3 quarks  a baryon
This particle is also known as a________________
proton.

23. Ex. A certain particle is made up of 2
quarks: 1 ____ quark and 1 __________
quark. d u up
antidown
What is the total charge of the particle?
Add up the charges: u:
(+2/3) e
[(+2/3) + (+1/3)] e : d
(+1/3) e
= 1 e
Is this a baryon, a meson or a lepton?
2 quarks  a meson
p+ (positive pion).
This particle is also known as a ______________________

24. Ex. A certain particle is made up of
3 quarks: 1 _____ quark and 2 ________
quarks. d up
down d u
What is the total charge of the particle? u:
(+2/3) e
Add up the charges: d:
(-1/3) e
[(+2/3) + (-1/3) + (-1/3)] e d:
(-1/3) e
= 0 e
Is this a baryon, a meson or a lepton?
3 quarks  a baryon
This particle is also known as a_____________________
neutron.

25. Ex. A certain particle is made up of
3 quarks: 2 ________________ quarks
and 1 _________________ quark. u d
antiup u u
antidown d
What is the total charge of the particle?
u :
(-2/3) e
Add up the charges:
[(-2/3) + (-2/3) + (+1/3)] e
(-2/3) e
u :
= -1 e
d :
(+1/3) e u d u d u u u u
Compare this one: to: d d
The left-hand particle is an _______________________ . It is
an example of ___________________ . It has the __________
mass as the proton, but the _________________ charge.
antiproton
same
antimatter
opposite

26. quark content total charge type name s -1e meson K- d baryon S- b U L
Determine the charge and type of each particle.
quark content
total
charge
type
name s
-1e
meson K- d
baryon S- b U L n u
+1e K+ u b u d s d d u s
The total charge must be ____________________________
a whole number of e's

27. What is matter made up of?
neutron or
a proton

28. planets, solar systems, etc
Forces
The Fundamental __________________ of Nature:
force
range
relative strength
what it
controls
strong
nuclear
very
short 1
holds nucleus
together
electro-
magnetic
infinite
(1/r2)
10-2
electricity and
magnetism
weak
very short
10-13
radioactive decay
gravita-
tional
10-38
planets, solar systems, etc

29. Ex: How can gravity hold Earth to the Sun if it is the
weakest force?
Earth and Sun have a lot of ______________
Earth and Sun are _________________ , so the
__________________________ force is not important.
3. Earth and Sun are_______________ , so the
________________________ forces are not important.
mass.
neutral
electromagnetic
far apart
two nuclear
Ex: The total amount of mass-energy in the universe
is:
ordinary matter: ______% (baryons and leptons)
dark matter: ______% (unknown)
dark energy: ______% (unknown) 5 23 72

30. Conservation Laws:
Total before =________________
Total after
Charge q
1. _____________________ is always conserved.
q1 + q2 + … =
q1’ + q2’ + …
In the absence of_______________ , ________________
is always conserved.
momentum (p)
friction =
p1’ + p2’ + …
p1 + p2 + …
3. In the absence of________________, ________________
is always conserved.
friction
energy (E)
Classical physics:
Modern physics:
ET ET’ =
mass-E mass’-E’ =
KE + PE KE’ + PE’
using E = mc2