Questions
1. Has anyone ever seen the track of a Δ in their detector?
2. What is the Breit-Wigner form?
3. The Δ “seen” in πN (N = p or n) scattering. How big is
the cross section on resonance relative to the unitarity
bound? (cm momentum ≈ 230 MeV, σ ≈ 195 mb)
3. The Δ is listed with the following properties:
a) m = 1230 MeV
b) Γ = 110 MeV
c) I = 3/2
d) J = 3/2
What features of the cross section lead you to conclude
that it exists and has each of these properties?
4. If, for a given process, I tell you that the matrix element
is independent of the kinematic variables (within the
kinematically allowed region), can you give me a formula
for the differential corss section? What is it called?
5. How do you tell that there is a ρ in πp → ππp?