Download Problems for particle physics course:

Exercise Set 2. (deadline Dec 11, 2002)
1. ParticleA at rest , decays into particles B and C
a) Find the energy of the outgoing particles, in terms of the various masses.
b) Find the magnitudes of the outgoing momenta.
2. ParticleA(energy E) hits particle B (at rest), producing particles C1, C2, …, Cn:
A+B  C1 + C2 + … + Cn. Calculate the threshold (i.e. minimum E) for this reaction, in terms of
the various particle masses.
3. In a two-body scattering event,A+ B  C + D, it is convenient to introduce the Mandelstam variables
s = (pA + pB)2
t = (pA -- pC)2
u = (pA-- pD)2
a) Show that s + t + u = mA2 + mB2 + mC2 + mD2.
b) Find the CM (center-of-mass) energy ofA, in terms of s, t, u and the masses.
c) Find the Lab (B at rest) energy of A.
d) Find the total CM energy.
4. Show that “normal” quark configurations for bosons, M  ( q q ) , must satisfy the conditions
S  1 , I  1 , Q / e  1 . Have “exotic” mesons, i.e. mesons that do not satisfy these conditions, been
found?
5. Construct the quark wave functions for   with spin up and  with spin down.