Deck 30: Particle Physics

Question 1

The quark flavors are

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

Answer 1

up,down.

Question 2

Which of the following particles does not mediate the weak interaction?

A) W⁺
B) W^-
C) $\pi$ ⁰
D) Z⁰
E) All of these choices mediate this interaction.

Answer 2

$\pi$ ⁰

Question 3

A meson is

A) a bound triplet of quarks.
B) a bound triplet of antiquarks.
C) a bound quark-antiquark pair.
D) a bound system of four quarks and one antiquark.

Answer 3

a bound quark-antiquark pair.

Question 4

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 5

The charge on a particle that has quark structure uus is _____ e.

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

Question 6

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

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

Question 7

Not counting antiparticles,how many different leptons are there?

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

Question 8

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

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

Question 9

Mesons 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 10

Ordinary matter contains only the following quarks.

A) Strange
B) Bottom
C) Down
D) Charm

Question 11

Quarks come in how many flavors?

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

Question 12

The antineutron has a quark structure _________.

A) uud
B) udd
C) u $\overline{u}$ d
D) $\overline{u}~ \overline{d}~ \overline{d}$
E) ${ u } \bar { d } d$

Question 13

A Muon is

A) a Baryon.
B) a Lepton.
C) a Hadron.
D) a Proton.

Question 14

The quark structure of the neutron is ______.

A) uub
B) udb
C) udd
D) uds
E) u $\overline{u}$ d

Question 15

A bound quark-antiquark pair is a ________ while a bound quark triplet is a ________.

A) beta particle; proton
B) neutron; meson
C) meson; baryon
D) baryon; meson
E) neutrino; antineutrino

Question 16

Ordinary matter is made from what generation quarks?

A) 1^st
B) 2^nd
C) 3^rd
D) 1^st and 2^nd
E) 1^st,2^nd,and 3^rd

Question 17

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 18

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 19

If a reaction involving hadrons were written at the quark level as $\overline u { \text { d } } + \text { uud } \rightarrow \mathrm { d } \overline { \mathrm { s } } + \text { ? }$ ,what is the quark composition of the unknown last particle?

A) udd
B) $\text{ ud}\overline { d}$
C) uds
D) $\text { ud}\overline { s}$
E) More information is needed.

Question 20

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.

Question 21

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

A) red
B) blue
C) yellow
D) green
E) All of these are colors for the strong charge.

Question 22

Complete the following decay. $\pi$ ⁺ $\rarr$ ? + v _$\mu$

A) $\mu$ ^-
B) $\mu$ ⁰
C) $\pi$ ^-
D) $\pi$ ⁰
E) $\mu$ ⁺

Question 23

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

A) It becomes an electron.
B) It becomes a neutrino.
C) It becomes an electron and an electron neutrino.
D) It becomes an electron and an electron antineutrino.
E) Nothing; it stays a W^- particle.

Question 24

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 25

Which force grows stronger with increasing distance?

A) the force between quarks in colorless combinations
B) the force between charges with net charge zero
C) the force between masses
D) the force between magnets
E) None of these choices are correct.

Question 26

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 27

If the top quark has a mass of 175 GeV/c²,what is its mass in atomic mass units?

A) 175 u
B) 188 u
C) 163 u
D) 58 u
E) 19 u

Question 28

Isolated quarks were first observed in

A) 1938.
B) 1955.
C) 1976.
D) 2001.
E) Isolated quarks have not been observed.

Question 29

Complete the following decay. $\mu$ ^- $\rarr$ e^- + ? + v $\mu$

A) n
B) $\pi$ ⁰
C) $\mathrm { v } _ { e }$
D) $\bar { v } _ { e }$
E) $\gamma$

Question 30

Gluons can emit

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

Question 31

What is the missing particle X in the reaction $\bar { v } _ { \mu } + \mathrm { P } \rightarrow \mathrm { n } + \mathrm { X }$ ?

A) e⁺
B) $\tau$ ⁺
C) $\mu$ ⁺
D) $\pi$ ⁺
E) p

Question 32

Which of the conservation laws listed below is violated by the reaction $\pi$ ⁺ + p $\rarr$ p + $\pi$ ^- ?

A) baryon number
B) electron-lepton number
C) muon-lepton number
D) charge
E) tau-lepton number

Question 33

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 34

What is the particle X in the reaction $\mathrm { p } + \overline { \mathrm { p } } \rightarrow \pi ^ { + } + \mathrm { X }$ ?

A) $\pi$ ⁰
B) $\pi$ ^-
C) e^-
D) $\overline { \mathrm { p } }$

Question 35

Photons play the role of exchange particles for the electromagnetic field in a manner similar to _______,which play this role for the strong interaction.

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

Question 36

The Z⁰ boson is a mediator of weak interactions.It mass is 93 GeV/c².About what is the range of this weak interaction?

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

Question 37

Which of the following particles is considered not elementary?

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

Question 38

Immediately after the Big Bang,how many types of interaction were there?

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

Question 39

What is the Q of the reaction p + p $\rarr$ p + p + $\pi$ ⁰? The rest mass of the proton is 938 MeV/c² and of the neutral point is 135 MeV/c².

A) 187 MeV
B) 135 MeV
C) 938 MeV
D) -187 MeV
E) -135 MeV

Question 40

The neutral pion decays by $\pi$ ⁰ $\rarr$ 2 $\lambda$ .The rest 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
E) This decay cannot happen.

Question 41

SLAC is an abbreviation for a

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

Question 42

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

Question 43

An electron and a positron,each having kinetic energy 1.843 GeV, 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 44

Which of the following particles interact via the strong interaction?

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

Question 45

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

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

Question 46

The exchange particle that mediates the strong interaction is the

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

Question 47

The LEP/LEC is located in

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

Question 48

The weak interaction is mediated by

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

Question 49

Which of the fundamental interactions governs the following decay? $\pi ^ { + } \longrightarrow e ^ { + } + \nu$

A) Strong nuclear
B) Electromagnetic
C) Gravitational
D) Weak nuclear

Question 50

The standard theory does not include which interaction?

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

Question 51

The neutrino does not

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

Question 52

The most recent unification of the fundamental forces was for the forces

A) electromagnetism and gravity.
B) electromagnetism and strong.
C) strong and weak.
D) gravity and weak.
E) weak and electromagnetism.

Question 53

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

A) $b \bar { c }$
B) $\mathrm { c }\bar { c }$
C) $\mathcal { u }\bar {a }$
D) $a \overline { s }$
E) $\mathrm { u }\bar { c}$

Question 54

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

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

Question 55

In brane-world theory,there are more _______ than we are accustomed to.

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

Question 56

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 57

Which of the fundamental interactions governs the following decay? $\pi ^ { 0 } \rightarrow \gamma + \gamma$

A) Weak nuclear
B) Electromagnetic
C) Gravitational
D) Strong nuclear

Question 58

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

A) $s\overline { c }$
B) $a \bar { u }$
C) $\mathcal { u }\bar { a }$
D) $b \bar { c }$
E) $c \bar { u }$