Quarks & Antiquarks

Q1. Which of the following correctly gives the charge, baryon number and strangeness of an up quark?

Multiple Choice · 1 point

• · Charge = +2/3, baryon number = +1/3, strangeness = 0
• · Charge = -1/3, baryon number = +1/3, strangeness = 0
• · Charge = +2/3, baryon number = +1, strangeness = 0
• · Charge = +1/3, baryon number = +1/3, strangeness = 0

Q2. Which of the following correctly gives the charge of a strange quark?

Multiple Choice · 1 point

• · +2/3
• · +1/3
• · -1/3
• · -2/3

Q3. What is the strangeness of an anti-strange quark?

Multiple Choice · 1 point

• · -1
• · 0
• · +1
• · +2

Q4. Which quark combination makes up a proton?

Multiple Choice · 1 point

• · udd
• · uud
• · uds
• · uus

Q5. Which quark combination makes up a neutron?

Multiple Choice · 1 point

• · uud
• · dds
• · udd
• · uds

Q6. Which of the following correctly gives the quark composition of an antiproton?

Multiple Choice · 1 point

• · ūd̄d̄
• · ūūd̄
• · uud
• · d̄d̄s̄

Q7. A π⁺ pion has a charge of +1. Which quark-antiquark combination is consistent with this?

Multiple Choice · 1 point

• · uū
• · dd̄
• · ud̄
• · dū

Q8. Which of the following quark combinations correctly represents a K⁺ kaon, which has charge +1 and strangeness +1?

Multiple Choice · 1 point

• · us
• · ds̄
• · us̄
• · sd̄

Q9. In β⁻ decay, a neutron decays into a proton. Which of the following correctly describes the quark change that takes place?

Multiple Choice · 1 point

• · An up quark changes into a down quark
• · A down quark changes into an up quark
• · A strange quark changes into a down quark
• · An up quark changes into a strange quark

Q10. Put the following in order to describe β⁻ decay at the quark level.

Ordering · 1 point

• 1. A neutron (udd) is present in the nucleus
• 2. A down quark emits a W⁻ boson and changes into an up quark
• 3. The neutron becomes a proton (uud)
• 4. The W⁻ boson decays into an electron and an electron antineutrino