Deck 30: Particle Physics

Question 1

Baryons are composed of

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

Answer 1

three quarks of three different colors.

Question 2

Mesons are composed of

A) a quark and antiquark of different colors.
B) a colorless quark-antiquark pair.
C) any two quarks.
D) three quarks of matching color.
E) any quark-antiquark combination.
F) three quarks of three different colors.

Answer 2

a colorless quark-antiquark pair.

Question 3

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 $\mathrm{X}$ in the following reaction? $\rightarrow \overline{\mathrm{n}}+\mathrm{X}$

A) $\tau$
B) $\pi^{-}$
C) $\mathrm{e}^{-}$
D) $\mu^{-}$
E) $\bar{p}$

Answer 3

$\mu^{-}$

Question 4

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 $\mathrm{X}$ in the following decay? $\quad \pi^{+} \rightarrow X+v_{\mu}$

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

Question 5

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? $\mu^{-+} p \rightarrow n+X$

A) $\gamma$
B) $\mathrm{v}_{\mu}$
C) $\pi^{0}$
D) $\mathrm{e}^{-}$
E) $\mathrm{v}_{\mathrm{e}}$

Question 6

The LHC is located at CERN in

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

Question 7

Accelerated electron beams are often used to study features of atoms on the surfaces of materials. If you wanted to alter the design of an electron accelerator to produce an electron beam appropriate for the studying the nuclei of atoms instead, what would be the appropriate alteration?

A) Decrease the transverse beam size
B) Increase the transverse beam size
C) Decrease the number of electrons per unit time in the beam
D) Increase the number of electrons per unit time in the beam
E) Increase the energy of the electrons in the beam
F) Decrease the energy of the electrons in the beam