Quarks

What are quarks?

• fundamental particles

• they make up hadrons

What type of quarks are protons and neutrons made of?

up and down quarks

Different types of quarks

• Up

• Down

• Strange

• Top

• Bottom

• Charm

• their antiquark equivalents

Why don’t we see top and bottoms often in nature?

they are very stable

How was the top quark predicted?

Using the symmetry of the model

What are baryons made of?

3 quarks

What quarks are in a proton?

uud

What quarks are in a neutron?

udd

What are mesons made of?

quarks and antiquarks

What are pions made of?

combination of u, d, anti u, anti d quarks

2 only

Pi + = u and anti down

Pi 0 = u and anti up, or d and anti down

Pi - = d and anti up

What are kaons made of?

they are made of quarks and anti-quarks including strange

• they have a strangeness

K + = u and anti strange

K 0 = d and anti strange

(Anti K +) K - = s and anti up

Anti K 0 = s and anti down

What is the strangeness of a strange?

-1

What happens when you try to break down a proton?

• there no such thing as free quarks

• Pair production causes the quark to spit into a quark and antiquark

What is quark confinement?

The idea that there is no such thing as a free quark

What is conserved in a particle interaction?

• Energy and momentum

• Charge

• Baryon number

• Lepton number (different lepton numbers are conserved separately)