Week 4 Lesson 2 Hadrons

Week 4 Lesson 2 Hadrons

Lesson goal: To understand the composition of mesons and baryons in terms of quarks

Let's start with a quick revision

Multiple Choice

A point source Q is placed on a square grid as shown below.

Which of the following points experience equal magnitudes of electric field strength?

• B and E

• A, B and C

• A and C

• A, E and C

Multiple Choice

A certain string just breaks when it is under 400 N of tension. A boy uses this string to whirl a 10 kg stone in a horizontal circle of radius 10 m. The boy continuously increases the speed of the stone.

Determine the speed at which the string will break.

• 20 m s^-1

• 80 m s^-1

• 400 m s-1

• 10 m s^-1

Multiple Choice

Determine the energy of the 3rd orbit in an H-atom, given that the ground state is -13.6 eV.

• -1.51 eV

• + 1.51 eV

• - 13.6 eV

• - 3.40 eV

Multiple Choice

Which quark has a charge of +2/3 e?

• d

• s

• t

• b

Elementary particles

• In general, there are three general types of elementary particles in the standard model: 

  
  

• Hadrons: particles made of quarks

  
  

• Leptons: particles not made of quarks

  
  

• Force carriers: gluon and gauge bosons 

Hadrons

• Hadrons are particles composed of quarks. Please be aware that not all particles are hadrons, for example gluons and gauge bosons are not hadrons (we'll learn about them next week).

• There are two types of Hadrons:

• Mesons: consist of two quarks.

• Baryons: consist of three quarks.

Let's finish with a quick quiz

Multiple Choice

Which combination of quarks can form a meson?

• u d

• d d

• u u

• u $\overline{d}$

Multiple Choice

Which of the following is a baryon?

• electron

• proton

• pion

• electron nutrino

Multiple Choice

What is the charge of a baryon made of sss?

• +1 e

• -1 e

• 0 e

• -1/3 e

Multiple Choice

Which of the following lepton is a 0 charge particle?

• electron

• muon

• anti-tau

• tau nutrino

Homework: complete check your learning 13.1 (due by Thursday's lesson)