Deck 30: Particle Physics

Question 1

Which of the following is not an abbreviation for a quark flavor?

A) u
B) s
C) b
D) t
E) r

Answer 1

r

Question 2

Ordinary matter contains only the following quarks

A) strange and charm.
B) bottom and top.
C) up and down.
D) right and left.

Answer 2

up and down.

Question 3

That matter is composed of quarks was first proposed by

A) Blatt and Weiskopf.
B) Gell-Mann and Zweig.
C) Rutherford and Geiger.
D) Bardeen and Cooper.
E) Feynman and Schwinger.

Answer 3

Gell-Mann and Zweig.

Question 4

Quarks come in how many flavors?

A) 2
B) 3
C) 4
D) 5
E) 6

Question 5

Baryons are composed of

A) any odd number of quarks.
B) three quarks of matching color.
C) three quarks of three different colors.
D) a colorless quark-antiquark pair.

Question 6

In terms of e, what is the charge of a particle whose quark composition is uds?

A) 0
B) 1
C) −1
D) 2
E) −2

Question 7

Quark flavors include

A) up, down.
B) red, green.
C) muon, pion.
D) cyan, magenta.
E) lepton, gluon.

Question 8

The proton has the quark structure

A) uud
B) udd
C) uūd
D)
E) ddd

Question 9

In terms of e, the charge on a particle that has quark structure uus is

A) 0
B) 1
C) −1
D) 2/3
E) −4/3

Question 10

A bound quark-antiquark pair is called a

A) proton.
B) neutron.
C) meson.
D) baryon.
E) lepton.

Question 11

A particle with a quark structure ds̄ is a

A) baryon.
B) lepton.
C) meson.
D) proton.

Question 12

Ordinary matter only contains which generation(s) of quarks?

A) I
B) II
C) III
D) I and II
E) I, II, and III

Question 13

Not counting antiparticles, how many different leptons are there?

A) 2
B) 4
C) 6
D) 8
E) 10

Question 14

Which of the following particles does not take part in mediating the weak interaction?

A) W⁺
B) W⁻
C) π⁰
D) Z⁰
E) All these choices are involved in mediating the weak interaction.

Question 15

The electron antineutrino is which of the following types of particle?

A) meson
B) baryon
C) hadron
D) lepton
E) quark

Question 16

A muon is a

A) baryon.
B) lepton.
C) hadron.
D) proton.

Question 17

If a reaction involving hadrons were written at the quark level as ūd + uud → d + X, which of the following could be the quark composition of the unknown last particle X?

A) udc
B) uus
C) uds
D) u
E) cū

Question 18

The quark structure of the neutron is

A) uub
B) udb
C) udd
D) uds
E) uūd

Question 19

A bound triplet of quarks is called a

A) beta particle.
B) meson.
C) baryon.
D) lepton.
E) neutrino.

Question 20

Who is credited with first speculating that matter is composed of tiny unseen units?

A) Democritus
B) Aristarchus
C) Aristotle
D) Newton
E) Einstein

Question 21

Arrange the strong (S), electromagnetic (EM), weak (W), and gravitational (G) forces from weakest to strongest.

A) W, G, EM, S
B) W, G, S, EM
C) G, W, S, EM
D) G, W, EM, S
E) W, S, G, EM

Question 22

The neutron decays into a proton, electron, and an electron antineutrino. Into what does the antineutron decay?

A) a proton, positron, and electron antineutrino
B) an antiproton, positron, and electron neutrino
C) a proton, electron, and electron antineutrino
D) an antiproton, electron, and electron neutrino
E) an antiproton, electron, and electron antineutrino

Question 23

Hadrons that contain one or more strange quarks are called strange particles. When a strange hadron decays into particles that are not strange, it is a manifestation of the

A) electromagnetic interaction.
B) strong interaction.
C) weak interaction.
D) gravitational interaction.

Question 24

In addition to charge and baryon number, another conserved quantity in particle interactions is lepton number. The six leptons have lepton number +1, and their antiparticles have lepton number −1. The lepton numbers for each generation (electron, muon, tau) are separately conserved. For example, an electron has electron-lepton number +1, while the electron antineutrino has electron-lepton number −1. What is the missing particle X in the following decay? π⁺ → X + ν_μ

A) μ⁻
B) μ⁰
C) π⁻
D) π⁰
E) μ⁺

Question 25

Gluons can absorb and emit

A) electrons.
B) protons.
C) photons.
D) baryons.
E) gluons.

Question 26

In an accelerator, two protons collide head-on and the following reaction takes place: p + p → p + p + π⁰. What is the minimum kinetic energy of each initial proton for this reaction to occur? The mass of the proton is 938 MeV/c² and the mass of the neutral pion is 135 MeV/c².

A) 938 MeV
B) 187 MeV
C) 135 MeV
D) 67.5 MeV
E) 0 MeV

Question 27

Which of the following is not a color charge associated with the strong interaction?

A) red
B) blue
C) yellow
D) green
E) All of these are color charges for the strong interaction.

Question 28

In the weak interaction in the decay of the neutron, what happens to the W⁻ particle produced in the process?

A) It decays into an electron.
B) It decays into a neutrino.
C) It decays into an electron and an electron neutrino.
D) It decays into an electron and an electron antineutrino.
E) Nothing; it stays a W⁻ particle.

Question 29

The neutral pion decays by π⁰ → 2_ϒ. The mass of the neutral pion is 135 MeV/c². What is the energy of each of the photons if the pion is at rest when it decays?

A) 270 MeV
B) 135 MeV
C) 67.5 MeV
D) 1.02 MeV

Question 30

Which force does not diminish with increasing distance?

A) the force between quarks
B) the force between opposite charges
C) the force between masses
D) the force between magnets
E) None of these choices are correct.

Question 31

The exchange particles for the strong interaction are

A) positrons
B) quarks
C) leptons
D) gluons
E) muons

Question 32

One way to estimate the range of an interaction is by using the Heisenberg uncertainty principle. Assume that the uncertainty in the energy of an exchange particle is given by its rest energy and that the particle travels at nearly the speed of light. Under those assumptions, what is the approximate range of the weak interaction mediated by the Z⁰ particle, which has a mass of 91.2 GeV/c²?

A) 10⁻¹⁵ m
B) 10⁻¹⁸ m
C) 10⁻²¹ m
D) 10⁻²⁴ m
E) 10⁻²⁷ m

Question 33

In addition to charge and baryon number, another conserved quantity in particle interactions is lepton number. The six leptons have lepton number +1, and their antiparticles have lepton number −1. The lepton numbers for each generation (electron, muon, tau) are separately conserved. For example, an electron has electron-lepton number +1, while the electron antineutrino has electron-lepton number −1. What is the missing particle X in the following reaction? v_μ + → + X

A) e⁻
B) τ⁻
C) μ⁻
D) π⁻
E)

Question 34

Immediately after the Big Bang, how many types of interaction are there believed to have been?

A) 0
B) 1
C) 2
D) 3
E) 4

Question 35

The top quark has a mass of about 173 GeV/c². What is its mass in atomic mass units?

A) 175 u
B) 186 u
C) 163 u
D) 58 u
E) 19 u

Question 36

Which of the following particles not considered to be elementary?

A) the electron
B) the electron antineutrino
C) the neutron
D) the muon
E) the tau

Question 37

Which of the answer choices below could be the unknown particle X in the following reaction? p + → + X

A) π⁰
B) π⁻
C) e⁺
D) p
E)

Question 38

In addition to charge and baryon number, another conserved quantity in particle interactions is lepton number. The six leptons have lepton number +1, and their antiparticles have lepton number −1. The lepton numbers for each generation (electron, muon, tau) are separately conserved. For example, an electron has electron-lepton number +1, while the electron antineutrino has electron-lepton number −1. What is the missing particle X in the following reaction? μ⁻+ p → n + X

A) e⁻
B) π⁰
C) v_e
D) v_μ
E) γ

Question 39

Isolated quarks were first observed in

A) 1938.
B) 1955.
C) 1976.
D) 2012, with the discovery of the Higgs boson.
E) Isolated quarks have not been observed.

Question 40

Which of the conservation laws listed below would definitely be violated in the following reaction? π⁺ + p → p + π⁻?

A) baryon number
B) energy
C) momentum
D) charge

Question 41

The meson having which of the following quark contents has electric charge −e?

A) b
B) c
C) c
D) d
E) u

Question 42

In brane-world theory, there are extra

A) strings.
B) gluons.
C) monopoles.
D) dimensions.
E) leptons.

Question 43

The baryon having which of the following quark contents has electric charge −e?

A) csd
B) dds
C) uud
D) bbc

Question 44

Which of the fundamental interactions governs the following decay? π⁺ → e⁺ + v_e?

A) strong nuclear
B) electromagnetic
C) gravitational
D) weak nuclear

Question 45

Which of the following particles interact via the strong interaction?

A) gravitons
B) quarks
C) leptons
D) neutrinos
E) photons

Question 46

An electron and a positron, each having kinetic energy 1.843 GeV, collide head-on and annihilate, producing a proton and antiproton pair (M = 938.3 MeV/c²). What is the kinetic energy of the antiproton produced in this way?

A) 0.938 GeV.
B) 0.905 GeV.
C) 1.586 GeV.
D) 1.843 GeV.

Question 47

SLAC is an abbreviation for a

A) linear accelerator.
B) synchrotron.
C) storage lane.
D) machine at Fermilab.
E) machine at CERN.

Question 48

The standard model does not include which interaction?

A) electromagnetic
B) gravitational
C) weak
D) strong
E) It includes all of these choices.

Question 49

The neutrino does not

A) have electric charge.
B) interact with other particles.
C) have momentum.
D) have energy.
E) have mass.

Question 50

The LHC is located at CERN in

A) Germany and Poland.
B) Switzerland and France.
C) France and Belgium.
D) the United States and Canada.
E) Texas.

Question 51

LHC stands for

A) Lorentz Heavy Centrifuge.
B) Level Height Charges.
C) Laser Hertz Catalyzer.
D) Large Hadron Collider.
E) None of these choices are correct.

Question 52

The baryon having which of the following quark contents is electrically neutral?

A) dds
B) bbc
C) uud
D) ucs

Question 53

The weak interaction is mediated by

A) gluon.
B) photon.
C) mesons.
D) W⁺, W⁻, Z⁰.
E) leptons.

Question 54

The exchange particle that mediates the strong interaction is the

A) gluon.
B) photon.
C) graviton.
D) neutrino.

Question 55

Which of the fundamental interactions governs the following decay? π^o → y + y

A) weak nuclear
B) electromagnetic
C) gravitational
D) strong nuclear

Question 56

The most recent unification of fundamental forces included which interactions?

A) electromagnetic and gravitational
B) electromagnetic and strong
C) electromagnetic and weak
D) strong and weak
E) gravitational and weak

Question 57

The meson having which of the following quark contents is electrically neutral?

A) s
B) d
C) u
D) b
E) c

Question 58

An accelerator that slams particles moving in opposite directions into one another is called a

A) collider
B) synchrotron
C) linear accelerator
D) storage ring
E) de Broglie modulator