Particle Physics

Question 1

Describe what happens when a positron collides with an electron

Answer 1

Electron and positron annihilate and two photons are produced/emitted

Question 2

Strong Nuclear

Answer 2

• Only hadrons
• Exchange particle: Gluon
• responsible for binding baryons together

Question 3

Weak nuclear

Answer 3

• hadrons and leptons
• Exchange particle: W+ and W- bosons
• beta decay

Question 4

Electromagnetic

Answer 4

• charged particles

- virtual photons

Question 5

Up (charge)

Answer 5

2/3

Question 6

Down (charge)

Answer 6

-1/3

Question 7

Strange (charge)

Answer 7

-1/3

Question 8

neutrinos (charge)

Answer 8

0

Question 9

electron (charge)

Answer 9

-1

Question 10

proton (formation)

Answer 10

uud

Question 11

neutron (formation)

Answer 11

udd

Question 12

mesons

Answer 12

kaon and pions

Question 13

pion + (formation)

Answer 13

u (a)d

Question 14

pion - (formation)

Answer 14

(a)u d

Question 15

pion 0 (formation)

Answer 15

u (a)u

Question 16

kaon + (formation)

Answer 16

u (a)s

Question 17

kaon - (formation)

Answer 17

(a)u s

Question 18

kaon 0 (formation)

Answer 18

d a(s)

Question 19

Specific Charge

Answer 19

The ratio of charge to mass of a particle

Question 20

The charge of an electron/proton

Answer 20

(-)1.6 x 10^-19

Question 21

The mass of an electron

Answer 21

9.11 x 10^-31

Question 22

Mass of a proton/neutron

Answer 22

1.67 x 10^-27

Question 23

At what point is strong nuclear an attractive force

Answer 23

3-4fm down to 0.5fm

Question 24

power of a laser beam (equation)

Answer 24

Power of beam = nhf

n is the number of photons passing a fixed point per second

Question 25

1 EV is equal to

Answer 25

1.60 x 10^-19 J

Question 26

1 MEV is equal to

Answer 26

1.6 x 10^-13 J

Question 27

Leptons

Answer 27

Particles (and antiparticles) that do not interact through the strong interactions (e.g electrons and neutrinos). Leptons interact via weak interaction and electromagnetic interaction if charged.

Question 28

Hadrons

Answer 28

Particles (and antiparticles) that can interact through the strong interactions (e.g protons and neutrons). They also act via electromagentic interaction if charged. Apart from the proton, which is stable, hadrons decay through weak interaction.

Question 29

Rest energy (equation)

Answer 29

The products before - the kinetic energy of the products

Question 30

Baryons

Answer 30

Protons and all other hadrons that decay into protons (directly or indirectly) (also have three quarks)

Question 31

What happpens in interaction between a lepton and a hadron

Answer 31

A neutrino or anti neutrino can change into or from its corresponding charged lepton

Question 32

Conservation rules

Answer 32

Charge, baryon number, lepton number and strange

Question 33

electron capture

Answer 33

An orbital electron interacts with a proton in the nucleus via weak interaction and produces a neutron.

Question 34

What is not always conserved in a weak interaction?

Answer 34

Strangeness