What is the branching ratio for alpha decay to Pu-237?

[Dant_li]

Homework Statement

Hello, I’m in high school (junior) and I was reading this book in nuclear physics and they mention alpha decay and I search up and I found this photo with branching ratios. I get the concept itself. But I was wondering if someone could explain to me the branching ratios on the photo as well as why there’s no decay to ground state of 237Pu?

Relevant Equations

BR = ki/(k1+k2+....ki...+) = ki/k

I understand that In general, the branching ratio

for a particular decay mode is defined as the ratio of the number of atoms decaying by that decay mode to the number decaying in total. But I can’t get this specific branching ratio.

 

[trurle]

The decay paths which change the spin of nucleus by large amount (as for decay to ground state of Pu-237 - spin changes by 4 quantum units, from +0.5 to -3.5) are very improbable. It is called "forbidden transition"