1. The Quarks Inside Baryons
“3 quarks for Mr Mark”
James Joyce - Finegan’s Wake

2. Quark properties
If protons and neutrons are made of quarks what properties must they have?
They must conserve baryon number.
They must conserve spin.
They must conserve charge.

3. Deep inelastic scattering
In search of the deep structure of the proton

4. Positively charged
proton
If an electron is fired at a proton at moderate speed, the electron behaves as expected. It has a negative charge and it is deviated from its path when it comes near the positive charge of the proton.

8. quark
electrical charge
baryon number u ⅔ ⅓ d -⅓ -⅔

9. proton
neutron
u u d
u d d

10. NEUTRON
u d d
⅓+ ⅓+ ⅓
baryon no =1
⅔+(-⅓)+(-⅓)
charge =0

11. u u d
⅓+ ⅓+ ⅓
baryon no =1
⅔+(⅔)+(-⅓)
charge =1

12. particles
uuu
uud
udd
ddd

13. quark structure baryon number charge spin uuu 1 uud udd ddd particles+2
3/2
3/2 +1
3/2 -1
3/2

14. involved in strong interaction
HADRONS
involved in strong interaction
Baryons
Mesons
q q q

15. Mesons
quark antiquark pairs

16. Strange Baryons Live much longer than 10-23seconds
Generally around 10-10seconds
Λ0 Σ+ Σ- Σ0 Ξ0 Ξ-