A What are Z+, Z-, N+, and N- in the Axial Charge Definition?

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The discussion centers on understanding the terms Z+, Z-, N+, and N- in the context of calculating the axial charge (G_A) for isotopes, particularly Germanium-73. Participants clarify that Z+ and Z- represent the number of protons with spin up and down, while N+ and N- represent the corresponding neutron counts. The axial charge is noted to be zero for nuclei with zero spin, but Germanium-73 has a spin of (9/2+), indicating unpaired nucleons. The user seeks confirmation on their assumed values for Z+ and Z-, and N+ and N-, which are proposed as 16, 16, 21, and 20, respectively. Accurate calculations of G_A depend on these values, emphasizing the importance of understanding nuclear spin states.
angweieng
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Understand N+, N-, Z+, and Z- and how to calculate them with spin consideration.
Hi all,

I was trying to understand an equation where:
axial charge, ##G_A=g^P_A(Z_+-Z_-)+ g^N_A(N_+-N_-)##

What is the meaning of ##Z_+## , ##Z_-##, ##N_+## and ##N_-##? From the article I read, axial charge will be zero when the nuclei has zero spin. What if I have Germanium 73 which has (9/2+) spin? How do I calculate for ##Z_+## , ##Z_-##, ##N_+## and ##N_-##?

##g^P_A## and ## g^N_A## here have constant values.

I don't have background of high energy physics but need the equation for my work, I really appreciate any help for this! Thank you so much!
 
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angweieng said:
Summary:: Understand N+, N-, Z+, and Z- and how to calculate them with spin consideration.

From the article I read, axial charge will be zero when the nuclei has zero spin.
What article was one reading?
angweieng said:
Summary:: Understand N+, N-, Z+, and Z- and how to calculate them with spin consideration.

What if I have Germanium 73 which has (9/2+) spin?

Wouldn't the Z+,Z-;N+,N- be the number of spin states (+,-) respectively, where Z and N represent the number of protons and neutrons, respectively, in those spin states? To have a spin +9/2, means the 9 nucleons are unpaired.

Is one asking how to predict 73Ge will have +9/2 spin?

Is one particularly interested in 73Ge? 93Nb and 113In are also stable odd(Z)-even(N) nuclides with +9/2.
 
Astronuc said:
What article was one reading?Wouldn't the Z+,Z-;N+,N- be the number of spin states (+,-) respectively, where Z and N represent the number of protons and neutrons, respectively, in those spin states? To have a spin +9/2, means the 9 nucleons are unpaired.

Is one asking how to predict 73Ge will have +9/2 spin?

Is one particularly interested in 73Ge? 93Nb and 113In are also stable odd(Z)-even(N) nuclides with +9/2.
Hi, thank you so much, the reason I ask to identify the ##Z_+## and ##Z_-## or ##N_+## and ##N_-## because I wish to calculate ##G_A## value. Assuming that I know the constant values of ##g^p_A## and ##g^N_A##, what is the ##Z_+## and ##Z_-## or ##N_+## and ##N_-##?

Now I understand that ##Z_+## and ##Z_-## mean the number of proton with spin up and spin down (same goes to neutron). In my case, my interested isotope is Ge73. In this case can I assumed that:
##Z_+## = 16, ##Z_-## = 16
##N_+## = 21, ##N_-## =20

Is it correct? Thank you so much again.
 
Theoretical physicist C.N. Yang died at the age of 103 years on October 18, 2025. He is the Yang in Yang-Mills theory, which he and his collaborators devised in 1953, which is a generic quantum field theory that is used by scientists to study amplitudes (i.e. vector probabilities) that are foundational in all Standard Model processes and most quantum gravity theories. He also won a Nobel prize in 1957 for his work on CP violation. (I didn't see the post in General Discussions at PF on his...

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