1. n  p + e- + e -  e- + e +  Ne*  Ne +  N  C + e + + e
The transition rate, W (the “Golden Rule”) of initialfinal
is also invoked to understand
ab+c (+  )
decays
Some observed decays
n  p + e- + e
-  e- + e + 
Fundamental particle decays
Ne*  Ne + 
N  C + e + + e
Pu  U +  20 10 20 10 13 7 13 6
Nuclear decays
236 94
232 92
How do you calculate an “overlap” between ???

5. J conserved. Any decay that’s possible will happen!
It almost seems a self-evident statement:
Any decay that’s possible will happen!
What makes it possible?
What sort of conditions must be satisfied?
Total charge q conserved.
J conserved.

6. Nuclear Coulomb potential potential Tunneling
finite (but small) probability
of being found outside
the nucleus at any time
always some probability of a
piece of the nucleus escaping
the nuclear potential
Nuclear
potential
Coulomb potential
with a STATIC POTENTIAL this probability is CONSTANT!

7.  must be expressed as a probability per unit time
probability of decaying
(at any time - now or later)
= 
constant
???? What’s this mean equally
likely at any instant ????
 must be expressed as a probability per unit time
If we observe one, isolated nucleus
it is equally likely it decays
this moment t
as any other moment t
(even years from now)
It either decays or it doesn’t.

8. Suppose a given particle has a 0.01 probability
of decaying in any given sec.
Does this mean if we wait 100 sec it will definitely have decayed?
If we observe a large sample N
of such particles,
within 1 sec
how many can we expect to have decayed?
Even a tiny speck of material can include well over trillions and trillions of atoms!

9. # decays  N  t -constant this is what the  means! (counted by a
geiger counter)
the size of the
sample studied
 t
time interval of
the measurement
each decay represents a loss in the
original number of radioactive particles
fraction of particles lost
Note: for 1 particle this must be interpreted
as the probability of decaying.
This argues that:
-constant
this is what the  means!