1
$\begingroup$

Does anyone know where I can find the Isospin values for light nuclei (H, C,N, O, S, Cl, ..) in their ground state?

$\endgroup$
4
  • 1
    $\begingroup$ You know the quark content of the nuclei. So why don't you just apply the connection between quark content and isospin? $\endgroup$
    – ACuriousMind
    Nov 12, 2014 at 20:55
  • $\begingroup$ I know the connection between quarks and nucleons, but I am not interested to that higher energy scale. We can give Isospin projection value +1/2 to protons and -1/2 to neutrons as they form a Isospin multiplet, and therefore determine Isospin from the nucleons in a nucleus. I would like to know where I can find experimental data for this quantum number in nuclei of light elements. $\endgroup$
    – Caute
    Nov 12, 2014 at 21:15
  • $\begingroup$ This seems like two unrelated questions, which should be asked separately. $\endgroup$
    – user4552
    Nov 13, 2014 at 1:44
  • $\begingroup$ Ben, I think you are right. $\endgroup$
    – Caute
    Nov 13, 2014 at 11:15

1 Answer 1

1
$\begingroup$

The best place to look is the Evaluated Nuclear Structure Data File, hosted by the National Nuclear Data Center at Brookhaven National Lab. For example, the data file for helium-4,
he-4
shows that the first two states with isospin $T\neq 0$ are the negative-parity states centered at 23.3 and 23.6 MeV.

Be warned that at modest proton number $Z$ the assumption underlying isospin symmetry, namely that protons and neutrons can be treated symmetrically inside the nucleus, starts to break down and it may no longer be possible to assign a definite isospin to a state. For example neon-20, an "alpha-cluster" nucleus, is assigned a $T=0$ ground state, but neon-21 has isospin assignments only for some excited states and neon-22 seems to have no isospin-assigned states at all. The next alpha-cluster nucleus, magnesium-24, has no isospin assignment in the ground state and several excited states labeled "T=0 and 1". You can compare this to the orbital angular momentum mixing that makes the ground states for deuterium and helium-4 into complicated mixtures of $S$ and $D$ waves.

$\endgroup$
0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.