Particle Physics

Question 1

What are the three main types of fundamental particles?

Answer 1

Quarks, Leptons, Bosons

Hadrons are also mentioned as a category of particles that interact via the strong nuclear force.

Question 2

What are the two types of hadrons?

Answer 2

Mesons and Baryons

Mesons contain 2 quarks, while baryons contain 3 quarks.

Question 3

What are the three types of quarks (that we need to know about)?

Answer 3

Up, Down, Strange

Question 4

What is the most stable baryon?

Answer 4

Proton

All free baryons will eventually decay into protons.

Question 5

What is the half-life of a free neutron?

Answer 5

About 15 minutes

Question 6

What are the two types of mesons (that we need to know about)?

Answer 6

Pions and Kaons

Question 7

What is the strangeness of a strange quark?

Answer 7

-1

Question 8

What is the charge of a strange quark?

Answer 8

-1/3

Question 9

What are antibaryons comprised of?

Answer 9

Three anti-quarks

Question 10

What is the charge of an anti-up quark?

Answer 10

-2/3

Question 11

What are the four types of leptons?

Answer 11

Electrons, Muons, Tau, Neutrinos

Question 12

What is the role of (gauge) bosons in particle physics?

Answer 12

Force carriers/exchange particles

Question 13

What is the exchange particle for the strong nuclear force?

Answer 13

Gluon or Pion

Question 14

Which particles does the weak nuclear force affect?

Answer 14

Hadrons and Leptons

Question 15

What is the exchange particle for the electromagnetic force?

Answer 15

Photon

Question 16

What is specific charge?

Answer 16

Charge per unit mass

Question 17

Units of specific charge?

Answer 17

Coulombs per kilogram

Question 18

What is the atomic mass unit (u)?

Answer 18

1/12th the mass of a Carbon-12 nucleus (or in other words, it’s the average mass of a bound nucleon)

Question 19

What is the formula for calculating the specific charge of a nucleus?

Answer 19

Q_s = Q/m

Question 20

True or False: The strong nuclear force becomes repulsive at short distances.

Answer 20

True

Question 21

What is the specific charge of a nucleus calculated from?

Answer 21

Charge and mass of the nucleus

Question 22

What does the term ‘specific charge’ refer to?

Answer 22

Charge to mass ratio of a particle

Question 23

What is the force that keeps electrons in orbit around a nucleus?

Answer 23

Electromagnetic force

Question 24

What is the charge of an anti-down quark?

Answer 24

+1/3

Question 25

What is the role of gluons in the strong nuclear force?

Answer 25

Bind quarks to one another within a nucleon

Question 26

What is a nucleon?

Answer 26

A component of an atomic nucleus (i.e. a proton or a neutron)

Question 27

What three properties must be conserved in all particle interactions?

Answer 27

Charge, baryon number, lepton number ## Footnote Strangeness is conserved in interactions involving the strong nuclear force.

Question 28

What is a beta-minus decay?

Answer 28

A neutron rich nucleus decays, converting a neutron into a proton and emitting a beta particle (electron) and an anti-electron neutrino

Question 29

What is the baryon number of a quark?

Answer 29

+⅓

Question 30

What is the baryon number of an anti-baryon?

Answer 30

-1

Question 31

What is the baryon number of an anti-quark?

Answer 31

-⅓

Question 32

What is the baryon number of a pion?

Answer 32

0

Question 33

What additional conservation rule applies to lepton number?

Answer 33

Each type of lepton has it's own type of lepton number, which must also be conserved

Question 34

True or False: Mass and energy are conserved in particle interactions.

Answer 34

False

Question 35

How does the strong nuclear force relate to strangeness?

Answer 35

The SNF can create new strange particles (strange anti-strange pair)

Question 36

What does a Feynman diagram represent?

Answer 36

Particle interactions

Question 37

What particle was proposed by Wolfgang Pauli to account for missing energy in beta decay?

Answer 37

Neutrino

Question 38

What is electron capture?

Answer 38

An orbital electron interacts with a proton, changing it into a neutron and emitting an electron neutrino

Question 39

Pair production occurs when a highly energetic photon decays into..

Answer 39

A particle and an anti-particle

Question 40

What is the minimum energy required for pair production to occur?

Answer 40

At least 1.022 MeV (twice the rest energy of an electron)

Question 41

What is alpha decay?

Answer 41

Ejection of an alpha particle from a large atomic nucleus

Question 42

What happens to the mass number and atomic number during alpha decay?

Answer 42

Mass number decreases by 4, atomic number decreases by 2

Question 43

What occurs during gamma decay?

Answer 43

Release of a photon by an excited nucleus

Question 44

True or False: A gamma decay alters the configuration of a nucleus.

Answer 44

False