# How to extract quadrupole moment and its error from $\chi^2 < \chi^2 + 1$ surface?

I have following info: plot of $$\chi^2$$ minimization of 208-Rn Coulomb excitation data, Surface corresponds to regions $$\chi^2 < \chi^2 + 1$$ with error bars of 1$$\sigma$$, mean lifetime is 8 $$\pm$$ 0.05 ps. Using this I should be able to excract the quadrupole moment and its error from that Surface. In plot y-axis is $$ME_02$$ and x-axis $$ME_22$$ denoting transitional and diagonal matrix elements.

Any tips on what I should do ?

I took the minimum$$\chi^2$$ valued from the graph, it was 0.35 and drew the 1$$\sigma$$ error bars to that.

• I don’t see how a surface or a region is defined by $\chi^2<\chi^2+1$, since this is equivalent to $0<1$, which is trie everywhere. – G. Smith May 2 at 20:42
• Same but I did some googling and the $\chi^2$ after the < might be the minimum of $\chi^2$ instead of just$\chi^2$ like stated (though that was the exact formation) – Schcat May 3 at 1:28